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> Working with Content > Modeling and Geometry Scripting > Introduction to Geometry Scripting > Geometry Scripting Reference

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Geometry Scripting Reference

A reference for the Blueprint Nodes and Functions used with Geometry Scripting.

On this page

Asset and Component Read/Write
Primitive Generation
Transform and Deformation
Composition and Decomposition
Mesh Modeling
Mesh Selections
Modify Mesh by Selection
- Transform Mesh
- Materials and PolyGroups
- Mesh Modeling
Subdivision
Simplification
Box
Normals
Cleanup and Repair
Low-Level Mesh Queries
Low-Level Mesh Building
Low-Level List Management
Low-Level Math
Mesh Sampling
Ray
Material ID
Vertex Values
Texture Sampling and Creation
Baking
UV
PolyGroup
Bone Weight
Mesh Geometric Queries
Mesh Geodesic
Simple Polygon
Polygon List
Poly Path
Mesh Comparisons
BVH & Spatial Queries
Utilities
Glossary

The Geometry Scripting library contains a very broad range of functionality, from low-level mesh construction and queries, such as building a mesh triangle-by-triangle or counting its vertices, to high-level operations like mesh booleans and intersection tests.

For more information on using the Geometry Scripting library, see Geometry Script Users Guide.

Most functions are available while working in the editor and at runtime. However, some are only available while working in the editor and have been noted in the tables below.

Asset and Component Read/Write

You can use these functions to read and write Dynamic Mesh instances, such as reading and writing to or from an existing or new Asset or Component.


Node Name	Description
Copy Mesh From Static Mesh	Extracts a Dynamic Mesh from a Static Mesh Asset.
Copy Mesh To Static Mesh	Updates a Static Mesh Asset with new geometry converted from a Dynamic Mesh.
Copy Mesh From Component	Extracts a Dynamic Mesh Actor from any supported Component type, in World or Local space.
Create New Volume From Mesh	Creates a new Volume Actor, such as a Blocking Volume, from a Dynamic Mesh Actor. This node only works in the Editor.
Create New Static Mesh Asset From Mesh	Creates a new Static Mesh Asset from a Dynamic Mesh Actor. This node only works in the Editor.
Set Static Mesh Collision From Mesh	Generates Simple Collision shapes for a Static Mesh Asset based on the input Mesh.
Set Dynamic Mesh Collision From Mesh	Generate Simple Collision shapes for a Dynamic Mesh Component based on the input Mesh.
Copy Collision Meshes From Object	Extracts the Collision Geometry from From Object and copies it with meshes stored in To Dynamic Mesh. For Simple Collision, From Object can be a Static Mesh Asset or any Primitive Component. For Complex Collision, From Object can be a Static Mesh Asset, Static Mesh Component, or Dynamic Mesh Component.
Reset Dynamic Mesh Collision	Clears Simple Collisions from the Dynamic Mesh Component.
Copy Mesh From Skeletal Mesh	Copies the Skeletal Mesh into the target Dynamic Mesh.
Copy Mesh To Skeletal Mesh	Copies the given Dynamic Mesh to the Skeletal Mesh.
Create New Skeletal Mesh Asset From Mesh	Create a new Skeletal Mesh Asset from the Target Mesh. This node only works in the Editor.

Primitive Generation

You can use these functions to generate and append a primitive mesh to the input Dynamic Mesh.


Node Name	Description
Append Box	Adds a 3D box to a specified Dynamic Mesh.
Append Sphere Lat Long	Adds a 3D Sphere triangulated using latitude/longitude topology to a Dynamic Mesh.
Append Sphere Box	Adds a 3D sphere triangulated using box topology to a Dynamic Mesh.
Append Capsule	Adds a 3D Capsule to a Dynamic Mesh.
Append Cylinder	Adds a 3D Cylinder (with optional end caps) to a Dynamic Mesh.
Append Cone	Adds a 3D cone to a Dynamic Mesh.
Append Torus	Adds a 3D torus (donut) or partial torus to a Dynamic Mesh.
Append Rectangle XY	Adds a planar Rectangle to a Dynamic Mesh.
Append Round Rectangle XY	Adds a planar Rectangle with Rounded Corners (RoundRect) to a Dynamic Mesh.
Append Disc	Adds a planar disc to a Dynamic Mesh.
Append Triangulated Polygon	Adds a Delaunay triangulation of a planar 2D polygon to a Dynamic Mesh.
Append Revolve Polygon	Adds the surface-of-revolution of a 2D polygon, full or optionally-capped partial revolution to a Dynamic Mesh.
Append Spiral Revolve Polygon	Revolves a 2D polygon on a helical path, like one used to create a vertical spiral.
Append Revolve Path	Revolves an open 2D path, with optional top and bottom end caps.
Append Simple Extrude Polygon	Extrudes a 2D polygon along a vertical path using a selected Dynamic Mesh.
Append Simple Swept Polygon	Sweeps a 2D polygon along an arbitrary 3D path using a selected Dynamic Mesh.
Append Linear Stairs	Adds a linear staircase using a selected Dynamic Mesh.
Append Curved Stairs	Adds a rising circular staircase using a selected Dynamic Mesh.
Append Mesh Transformed	Applies each transform to Append Mesh, then adds its geometry to the Target Mesh.
Append Sweep Polygon	Sweeps and rotates a 2D polygon along the Sweep Path to create a 3D mesh that appends to the provided mesh.
Append Voronoi Diagram 2D	Generates triangulated Voronoi Cells from the provided Voronoi Sites, identifying each with PolyGroups, and appends to the provided mesh.
Append Sweep Polyline	Sweep the given 2D Polyline Vertices along the Sweep Path specified as a set of FTransforms. If the 2D vertices are (U,V), then in the coordinate space of the FTransform, X points "along" the path, Y points "right" (U), and Z points "up" (V).
Append Bounding Box	Adds a 3D box to the Target Mesh with dimensions and origin taken from the input Box.
Append Delaunay Triangulation 2D	Generates a Delaunay Triangulation of the provided vertices, and appends it to the Target Mesh.
Append Polygon List Triangulation	Generates a Delaunay Triangulation of the provided Polygon List, and appends it to the Target Mesh.

Transform and Deformation

You can use these functions to manipulate the vertex positions of a Dynamic Mesh. These manipulations do not change the mesh topology or connectivity.


Node Name	Description
Translate Mesh	Applies a translation to the vertices of a Mesh.
Scale Mesh	Applies a scale transformation to the vertices of a Mesh.
Transform Mesh	Applies an arbitrary FTransform to the vertices of a Mesh.
Apply Bend Warp To Mesh	Applies a bend warp around an axis defined by a Transform.
Apply Twist Warp To Mesh	Applies a twist warp around an axis defined by a Transform.
Apply Flare Warp To Mesh	Applies a Flare or Bulge warp.
Apply Math Warp To Mesh	Applies various simple math-function-based warps, currently a 1D or 2D sine-wave with arbitrary orientation.
Apply Perlin Noise To Mesh	Applies a 3D Perlin noise displacement to the entire mesh or regions of the mesh defined by optional Selection.
Apply Iterative Smoothing To Mesh	Applies several mesh smoothing iterations to the entire mesh or a subset defined by the optional Selection
Apply Displace From Texture Map	Applies a displacement to a Dynamic Mesh based on a Texture2D and a UV channel.
Rotate Mesh	Rotates the mesh relative to the specified origin.
Translate Pivot To Location	Set the Pivot Location for the Mesh. Since the Pivot of a Mesh object is always the point at (0,0,0), this function simply translates the mesh by -PivotLocation.
Make Transform From Z Axis	Create a transform at the given location, with the ZAxis vector as the Z-axsis of the transform, and the X or Y axis oriented to the tangent vector, based on the `bTangentIsX` parameter.
Make Transform From Axes	Create a transform at the given location, with the ZAxis vector as the Z-axsis of the transform, and the X or Y axis oriented to the Tangent vector, based on the `bTangentISX` parameter.
Get Transform Axis Vector	Get the vector for the direction of the X, Y, and Z axis of the transform.
Get Transform Axis Ray	Get the ray at the transform location aligned with the direction of the X,Y, and Z-axis of the transform.
Get Transform Axis Plane	Get the plane at the transform location with the plane normal aligned with the direction of the X,Y, and Z-axis of the transform.

Composition and Decomposition

You can use these functions to combine meshes together, or split them apart.


Node Name	Description
Copy Mesh To Mesh	Copies the mesh from one Dynamic Mesh into another.
Get Sub Mesh From Mesh	Copies a list of triangles from one Dynamic Mesh to another.
Split Mesh By Components	Separates a mesh into parts, one for each connected component, drawn from a Dynamic MeshPool.
Split Mesh By Material IDs	Separates a mesh into parts, one for each Material ID, drawn from a Dynamic MeshPool.
Append Mesh	Adds the geometry from one mesh to another, with optional Transform.
Append Mesh Repeated	Adds the geometry from one mesh to another based on the number of times it should repeat, accumulating a transform each time. This operation is useful for making patterns.

Mesh Modeling

These functions provide standard high-level modeling operations, but are generally calling the low-level mesh processing code that the similarly-named Tool in Modeling Mode would call.


Node Name	Description
Apply Mesh Boolean	Applies a Boolean operation (such as, Union, Intersect, and Subtract) to a Dynamic Mesh based on a second mesh.
Apply Mesh Plane Cut	Applies a plane cut to a mesh, optionally filling any holes created.
Apply Mesh Plane Slice	Slices a mesh into two halves, with optional hole filling.
Apply Mesh Mirror	Mirrors a mesh across a plane, with optional cutting and welding of triangles.
Apply Mesh Offset	Moves the vertices of a mesh to an offset surface.
Apply Mesh Shell	Moves a copy of the mesh's triangles to an offset surface, and stitches them to the original triangles. For example, to create a thickened shell.
Apply Mesh Extrude	Extrudes the triangles of a mesh along a constant direction. For example, it creates a solid from an open triangulated polygon.
Apply Mesh Solidify	Replaces the mesh with a voxelized-and-meshed approximation (VoxWrap operation).
Apply Mesh Morphology	Replaces the mesh with an SDF-based offset mesh approximation.
Apply Mesh Self Union	An object performs a Boolean Union operation with itself, computing actions such as repairing self-intersections and removing floating geometry.
Apply Mesh PolyGroup Bevel	Applies Mesh Bevel operation to all PolyGroup Edges.

Mesh Selections

These functions identify regions of a mesh to different tools so they can operate locally. Several functions can work on the entire mesh or a subset defined by a Selection. Selection Types include: Triangle, Vertices, and PolyGroups.


Node Name	Description
Invert Mesh Selection	Invert the selection on the Target Mesh.
Create Select All Mesh Selection	Creates a selection of the given selection type containing all the elements of the Target Mesh
Convert Mesh Selection	Converts a mesh selection to a different type. By default, vertices map to triangles within a one-ring neighborhood, and triangles to all contained vertices.
Combine Mesh Selections	Combines two mesh selections into a new mesh selection. The two inputs, Selection A and Selection B must have the same type.
Convert Index Array To Mesh Selection	Creates a mesh selection from the Index Array.
Convert Index Set To Mesh Selection	Creates a mesh selection from the Index Set.
Convert Mesh Selection To Index Array	Converts a mesh selection to an Index Array.
Convert Index List To Mesh Selection	Creates a mesh selection from the Index List. For cases where the Index List Type does not match the Selection Type, Convert mesh selection with `bAllowPartialInclusion=true` is used to convert.
Convert Mesh Selection To Index List	Converts a mesh selection to an Index List.
Select Mesh Elements In Box	Creates a new mesh selection of the Selection Type for the Target Mesh by finding all elements contained in the Box.
Select Mesh Elements In Box With BVH	Create a new Mesh Selection of the Selection Type for the Target Mesh by finding all elements contained in the Box. Similar to Select Mesh Elements In Box but takes a BVH to make it work faster.
Select Mesh Elements In Sphere	Creates a new mesh selection of the Selection Type for the Target Mesh by finding all elements contained in the Sphere.
Select Mesh Elements With Plane	Creates a new mesh selection of the Selection Type for the Target Mesh by finding all elements on one side of the plane, particularly the side that the surface normal of a Plane points towards.
Select Mesh Elements By Normal Angle	Creates a new mesh selection of the Selection Type for the Target Mesh by finding all elements that have a normal vector that is within an angular deviation threshold from the given Normal. For Triangle and PolyGroup selections the triangle facet normal is used, for Vertex selections the per-vertex averaged normal is used.
Select Mesh Elements Inside Mesh	Creates a new mesh selection of the Selection Type for the Target Mesh by finding all elements inside a second Selection Mesh.
Expand Mesh Selection To Connected	Expands the Selection on the Target Mesh to connected regions and returns the New Selection.
Get Mesh Selection Bounding Box	Gets the 3D Bounding Box of a mesh selection.
Get Mesh Selection Boundary Loops	Computes the set of Vertex Loops bordering a mesh selection. Both the 3D polylines and lists of vertex indices are returned for each Loop. For a Vertex selection, this function returns the border loops around the one-ring neighborhood of the vertex selection. For a Vertex selection, this function returns the border loops around the one-ring neighborhood of the vertex selection.
Get Mesh Selection Info	Queries information about a mesh selection.
Debug Print Mesh Selection	Prints information about the mesh selection to the Output Log.
Expand Contract Mesh Selection	Grow or shrink the Selection on the Target Mesh to connected neighbors. For vertex selections, Expand includes vertices in one-ring of selected vertices, and Contract removes any vertices with a one-ring neighbor that is not selected. For triangle selections, add or remove triangles connected to selected triangles. For PolyGroup selections, add or remove PolyGroups connected to selected PolyGroups.

Modify Mesh by Selection

Functions for editing geometry from a given selection.

Transform Mesh


Node Name	Description
Transform Mesh Selection	Applies the given transform to the selected part of the mesh.
Translate Mesh Selection	Applies the given translation to the selected part of the mesh.
Rotate Mesh Selection	Rotates the selected part of the mesh relative to the specified origin.
Scale Mesh Selection	Applies the given scale to the selected part of the mesh.

Materials and PolyGroups


Node Name	Description
Set Material ID For Mesh Selection	Sets a new Material ID on all the triangles of the given Selection.
Set PolyGroup For Mesh Selection	Sets a new PolyGroup on all the triangles of the given Selection, for the given Group Layer.

Mesh Modeling


Node Name	Description
Apply Mesh Disconnect Faces	Disconnects the triangles of the Target Mesh identified by the Selection.
Apply Mesh Duplicate Faces	Duplicates the triangles of the Target Mesh identified by the Selection input.
Apply Mesh Linear Extrude Faces	Applies Linear Extrusion to the triangles of Target Mesh identified by the Selection.
Apply Mesh Offset Faces	Applies an Offset to the faces of the Target Mesh identified by the Selection, or all faces if Selection is empty.
Apply Mesh Inset Outset Faces	Applies an Inset or Outset to the faces of Target Mesh identified by the Selection, or all faces if the Selection is empty.
Apply Mesh Bevel Selection	Applies a Mesh Bevel operation to parts of Target Mesh using the Bevel Options settings.

Subdivision

These functions apply various mesh subdivision strategies to a Dynamic Mesh.


Node Name	Description
Apply PolyGroup Catmull Clark SubD	Apply Catmull Clark Subdivision to the PolyGroup Topology of the mesh (discards input triangulation). This node only works in the Editor.
Apply Triangle Loop SubD	Apply Loop Subdivision to the input mesh. This node only works in the Editor.
Apply Selective Tessellation	Tessellate the specified mesh selection using the indicated Pattern Type.
Apply PN Tessellation	Apply point-normal tessellation to the input mesh.
Apply Uniform Tessellation	Apply a uniform tessellation to the input mesh.

Simplification

These functions simplify a mesh using various strategies.


Node Name	Description
Apply Simplify To Triangle Count	Simplifies the mesh until a target triangle count is reached.
Apply Simplify To Vertex Count	Simplifies the mesh until a target vertex count is reached.
Apply Simplify To Tolerance	Simplifies the mesh to a target geometric tolerance. For example, any further simplification would result in a deviation from the input mesh larger than the tolerance.
Apply Simplify To Planar	Simplifies planar areas of the mesh that have more triangles than necessary. This does not change the 3D shape of the mesh.
Apply Simplify To PolyGroup Topology	Simplifies the mesh down to the PolyGroup Topology. For example, the high-level faces of the mesh PolyGroups. Another example would be on a default Box-Sphere where simplifying to PolyGroup topology produces a box.

Box

Utility functions for computing basic math functions for box objects.


Node	Description
Make Box From Center Size	Create a box from a center point, and X, Y, and Z dimensions.
Make Box From Center Extents	Create a box from a center point and X, Y, and Z extents. Extents are half-dimensions.
Get Box Center Size	Get the center point, and X, Y, and Z dimensions of a box.
Get Box Corner	Get the position of a corner of the box. Corners are indexed from 0 to 7, using an ordering where: 0 is the Min corner 1/2/3 are +Z/+Y/+X from the Min corner 7 is the Max corner 4/5/6 are -Z/-Y/-X from the Max corner
Get Box Face Center	Get the position of the center of a face of a box. Faces are indexed from 0 to 5, using an ordering where: 0 is the Min corner 1/2/3 are +Z/+Y/+X from the Min corner 7 is the Max corner 4/5/6 are -Z/-Y/-X from the Max corner
Get Box Volume Area	Get the volume and surface area of a box.
Get Expanded Box	Get the input box expanded by adding the Expand By parameter to both the Min and Max. Dimensions will be clamped to the center point if any of the Expand By parameters are larger than half the box size.
Get Transformed Box	Apply the input transform to the corners of the input box, and return the new box containing those points.
Test Box Box Intersection	Test if box 1 and box 2 intersect.
Find Box Box Intersection	Find the box formed by the intersection of box 1 and box 2.
Get Box Box Distance	Calculate the minimum distance between box 1 and box 2.
Test Point Inside Box	Test if a point is inside the box; returning true if so, otherwise false.
Find Closest Point On Box	Find the point on the faces of the box that is closest to the input point. If the point is inside the Box, it is returned.
Get Box Point Distance	Calculate the minimum distance between the box and the point.
Test Box Sphere Intersection	Check if the box intersects a sphere defined by the Sphere Center and Sphere Radius.

Normals

These functions recompute the normals of a mesh.


Node Name	Description
Flip Normals	Flips the mesh normals by reversing the orientation of each face.
Set Per Vertex Normals	Sets the mesh normals to per-vertex normals. For example, no split normals at any vertex.
Set Mesh To Facet Normals	Sets the mesh normals to per-face/triangle normals. For example, split normals along every edge of the mesh.
Compute Split Normals	Computes split-normals for the mesh based on an angle tolerance and/or other factors such as PolyGroup topology.
Recompute Normals	Recomputes the existing mesh normals. Preserves existing split normals. For use after mesh deformations, for example.
Compute Tangents	Recomputes tangents for the mesh (various methods).
Set Mesh Per Vertex Normals	Set all normals in the Target Mesh Normals Overlay to the specified per-vertex normals.
Get Mesh Has Tangents	Check if the target mesh has a Tangents Attribute Layer enabled.
Discard Tangents	Remove any existing Tangents Attribute Layer from the Target Mesh.
Compute Tangents	Recompute tangents for the Target Mesh, using the method specified by
Set Mesh Per Vertex Tangents	Set all tangents in the Target Mesh Tangents Overlays to the specified per-vertex tangents.
Get Mesh Per Vertex Tangents	Compute the interpolated Position, `A * Vertex1 + B * Vertex2 + C * Vertex3`, where (A,B,C) = BarycentricCoords and the Vertex positions are taken from the specified TriangleID of the target mesh.
Update Vertex Normal	Update the Normals and Tangents at VertexD of the Target Mesh.
Recompute Normals For Mesh Selection	Recompute the normals of Target Mesh on all the triangles/vertices of the given Selection using the given Calculate Options. This method will preserve any existing hard edges, that is each shared triangle-vertex normal is recomputed by averaging the face normals of triangles that reference that shared triangle-vertex normal.

Cleanup and Repair

You can use these functions to fix issues in a mesh, or to apply other standard repairs.


Node Name	Description
Compact Mesh	Compacts the mesh's vertices and triangles to remove any "holes" in the Vertex ID or Triangle ID lists (see discussion in Low-Level Mesh Queries section).
Discard Mesh Attributes	Removes the Attribute Set from a Dynamic Mesh, such as all UVs, Normals, Material IDs, Vertex Colors, and extended PolyGroup Layers. Note that this may prevent many functions from working.
Auto Repair Normals	This function tries to automatically reorient the Normals of a mesh so that they are consistent, such as fixing flipped normals.
Weld Mesh Edges	Welds any open boundary edges of the mesh together if possible in order to remove "cracks."
Fill All Mesh Holes	Tries to fill all open boundary loops (such as holes in the geometry surface) of a mesh.
Remove Small Components	Removes connected components of the mesh that have a volume, area, or triangle count below a threshold.
Remove Hidden Triangles	Removes any triangles in the mesh that are not visible from the exterior view, under various definitions of "visible" and "outside."
Resolve Mesh TJunctions	Attempts to resolve t-junction in the Target Mesh.
Split Mesh Bowties	Splits vertices in the Target Mesh that otherwise produce a bowtie where only a single vertex connects regions of the mesh.
Repair Mesh Degenerate Geometry	Modifies the Target Mesh by deleting small triangles or merging triangles until all edges are greater than a specified minimum length.

Low-Level Mesh Queries

These functions provide low-level information about the elements of a mesh. In this context, VertexID and TriangleID are integers.

In a Dynamic Mesh, there may be gaps in VertexID or TriangleID range — after vertices/triangles are deleted — and some operations (like Simplification) may return a mesh with gaps present. Gaps in the ID ranges are cleaned up using the Compact Mesh function.


Node Name	Description
Get Vertex Count	Gets the number of vertices in the mesh.
Get Num Vertex IDs	Gets the number of Vertex IDs in the mesh, which may be larger than the Vertex Count, if the mesh is not dense. For example, after deleting vertices.
Is Valid Vertex ID	Returns true if a Vertex ID refers to a valid vertex.
Get All Vertex IDs	Returns an IndexList of all Vertex IDs in mesh.
Get Vertex Position	Gets the 3D position of a mesh vertex, by Vertex ID.
Get All Vertex Positions	Returns a Vector List of all the mesh vertex positions. This list may be extensive.
Get Triangle Count	Returns the number of triangles in the mesh. Note that this is a function on the Dynamic Mesh directly.
Get Num Triangle IDs	Gets the number of Triangle IDs in the mesh. The number may be larger than the Triangle Count if the mesh is not dense, even after deleting triangles.
Is Valid Triangle ID	Returns true if a TriangleID refers to a valid Triangle.
Get All Triangle IDs	Returns an Index List of all Triangle IDs in a mesh.
Get Triangle Indices	Returns the vertex indices triplet for a Triangle.
Get All Triangle Indices	Returns a TriangleList of all Triangle indices triplets in a mesh.
Get Triangle Positions	Returns the three corner positions for a Triangle.
Get Triangle Face Normal	Returns the face/facet normal of a Triangle.
Get Triangle UVs	Returns the three corner UVs for a Triangle.
Get Triangle Material ID	Returns the current Material ID for a Triangle.
Get All Triangle Material IDs	Returns an Index List of all triangle Material IDs.
Get Triangle PolyGroup ID	Returns the current PolyGroup ID for a Triangle, in a given PolyGroup layer.
Get Has Vertex ID Gaps	Returns true if there are gaps in the Vertex ID list. For example, Get Number of Vertex IDs is greater than Get Vertex Count.
Get Has Triangle ID Gaps	Returns true if there are gaps in the Triangle ID list, such that Get Num Triangle IDs is greater than Get Triangle Count.
Get Is Dense Mesh	Returns true if the mesh is dense. For example, no gaps in Vertex IDs or Triangle IDs.
Get Mesh Has Attribute Set	Returns true if the mesh has an Attribute Set enabled to store UVs, Normals, Material IDs, and Vertex Colors. This is generally enabled by default.
Get Interpolated Triangle Position	Compute the interpolated Position, `A * Vertex1 + B * Vertex2 + C * Vertex3`, where (A,B,C) = BarycentricCoords and the Vertex positions are taken from the specified TriangleID of the target mesh.
Compute Triangle Barycentric Coords	Compute the barycentric coordinates (A,B,C) of the Points relative to the specified TriangleID of the Target Mesh.
Get Interpolated Triangle UV	Compute the interpolated UV, `A * UV1 + B * UV2 + C * UV3`, where (A,B,C) = BarycentricCoords and the UV positions are taken from the specified TriangleID in the specified UV Channel of the Target Mesh.
Get Triangle Normals	For the specified TriangleID of the Target Mesh, get the Normal and Tangent vectors at each vertex of the Triangle. These Normals and Tangents will be taken from the Normal and Tangents Overlays.
Get Interpolated Triangle Normal	Compute the interpolated Normal, `A * Normal1 + B * Normal2 + C * Normal3`, where (A,B,C) = BarycentricCoords and the Normals are taken from the specified TriangleID in the Normal layer of the Target Mesh.
Get Triangle Normal Tangents	For the specified TriangleID of the Target Mesh, get the Normal and Tangent vectors at each vertex of the Triangle. These Normals and Tangents will be taken from the Normal and Tangents Overlays.
Get Interpolated Triangle Normal Tangents	Compute the interpolated Normal and Tangents for the specified TriangleID in the Normal and Tangent attributes of the Target Mesh.
Get Has Vertex Colors	Return true if the Target Mesh has the Vertex Colors attribute enabled.
Get Triangle Vertex Colors	For the specified TriangleID of the Target Mesh, get the Vertex Colors at each vertex of the Triangle. These Colors will be taken from the Vertex Color Attribute.
Get Interpolated Triangle Vertex Color	Compute the interpolated Vertex Color, `A * Color1 + B * Color2 + C * Color3`, where (A,B,C) = BarycentricCoords and the Colors are taken from the specified TriangleID in the Vertex Color layer of the Target Mesh.

Low-Level Mesh Building

These functions construct a mesh triangle-by-triangle and perform other low-level mesh editing operations.

Using these functions in situations that involve looping over the elements of meshes with many thousands of triangles can be quite slow in Blueprint or Python scripting.


Node Name	Description
Set Vertex Position	Sets the 3D position of a mesh vertex.
Add Vertex To Mesh	Adds a new vertex to the mesh and returns a new Vertex ID.
Add Vertices To Mesh	Adds a list of vertices to the mesh.
Delete Vertex From Mesh	Removes a vertex from the mesh.
Delete Vertices From Mesh	Removes a list of vertices from the mesh.
Add Triangle To Mesh	Adds a triangle (3-element Vertex ID tuple) to the mesh.
Add Triangles To Mesh	Adds a list of triangles to the mesh.
Delete Triangle From Mesh	Removes a triangle from the mesh.
Delete Triangles From Mesh	Removes a list of triangles from the mesh.
Delete Triangles In PolyGroup	Deletes all triangles from the mesh that have a particular PolyGroup, in a specific PolyGroup layer.
Append Buffers To Mesh	Adds a set of vertices/triangles to the mesh, with attributes such as Normals and UVs. Similar to Create Mesh Section in Proc Mesh Component.
Set Mesh Triangle Normals	Sets the Normals of a mesh triangle.
Set Mesh Triangle UVs	Sets the UVs of a mesh triangle.
Set Triangle Material ID	Sets the Material ID of a mesh triangle.
Set All Mesh Vertex Positions	Set all vertex positions in the Target Mesh to the specified positions.

Low-Level List Management

These functions cover list management for: Index List, Scalar List, Vector List, UV List, and Color List.


Node Name	Description
Get Index List Length	Returns the number of items in the Index List.
Get Index List Last Index	Returns the index of the last item in the Index List.
Get Index List Item	Returns the item stored in the Index List at the specified location.
Set Index List Item	Updates the value of the item stored in the Index List at the specified location.
Convert Index List To Array	Converts an Index List to an array of integers.
Convert Array To Index List	Converts an array of integers to an Index List.
Duplicate Index List	Duplicates the contents Index List into Duplicate List.
Clear Index List	Resets all the items in the Index List to the Clear Value.
Get Scalar List Length	Returns the number of items in the Scalar List.
Get Scalar List Last Index	Returns the index of the last item in the Scalar List.
Get Scalar List Item	Returns the Scalar (double) stored in the Scalar List at the specified location.
Set Scalar List Item	Updates the value of the Scalar stored in the Scalar List at the specified location.
Convert Scalar List To Array	Converts a Scalar List to an array of doubles.
Convert Array To Scalar List	Converts an array of doubles to a Scalar List.
Duplicate Scalar List	Copies the contents of Scalar List into Duplicate List.
Clear Scalar List	Reset all the items in the Scalar List to the Clear Value.
Get Vector List Length	Returns the number of items in the Vector List.
Get Vector List Last Index	Return the index of the last item in the Vector List.
Get Vector List Item	Return the FVector stored in the VectorList at the specified location.
Set Vector List Item	Updates the value of the FVector stored in the Vector List at the specified location.
Convert Vector List To Array	Converts a Vector List to an array of FVectors.
Convert Array To Vector List	Converts an Array of FVectors to a Vector List.
Duplicate Vector List	Copies the contents of Vector List into Duplicate Vector List.
Clear Vector List	Resets all the items in the Vector List to the Clear Value.
Get UV List Length	Returns the number of items in the UV List.
Get UV List Last Index	Returns the index of the last item in the UV List.
Get UV List Item	Returns the FVector2D stored in the UV List at the specified location.
Set UV List Item	Updates the value of the FVector2D stored in the UV List at the specified location.
Convert UV List To Array	Converts a UV List to an array of FVector2Ds.
Convert Array To UV List	Converts an array of FVector2D to UVList.
Duplicate UV List	Duplicates the contents of UV List into Duplicate List.
Get Color List Length	Returns the number of items in the Color List.
Get Color List Last Index	Returns the index of the last item in the Color List.
Get Color List Item	Returns the FLinearColor stored in the Color List at the specified location.
Set Color List Item	Updates the value of the FLinearColor stored in the Color List at the specified location.
Convert Color List To Array	Converts the Color List to an array of FLinearColor.
Convert Array To Color List	Converts an array of FLinearColor to a Color List.
Extract Color List Channel	Creates a Scalar List that corresponds to the 0,1, or 2 channel of a Color List.
Extract Color List Channels	Creates a Vector List from a Color List. The channels in the Color List are mapped to vector components by means of X Channel Index, Y Channel Index, and Z Channel Index.

Low-Level Math

Functions that operate on the Vector Lists and Scalar Lists in a component wise fashion. The functions that take multiple lists, such as Vector Dot, require the lists to have the same number of elements.


Node Name	Description
Vector Length	Computes the length of each vector in Vector List A and returns the value in the Scalar List.
Vector Dot	Computes the dot-product between each pair of vectors in Vector List A and Vector List B, and returns the value in the new Scalar List.
Vector Cross	Computes the cross-product between each pair of vectors in Vector List A and Vector List B and returns the value in the new Vector List.
Vector Normalize In Place	Normalizes each vector in Vector List, and stores the value in a Vector List. If a vector is degenerate, set the normal to the Set On Failure vector.
Vector Blend	Computes `ConstantA * A + ConstantB * B` for each pair of vectors in Vector List A and Vector List B, and returns the value in the new Vector List. By default this (constants = 1) adds the two vectors. Set `ConstantB = -1` to subtract B from A. You can also use the function to Linear Interpolate, by setting `ConstantB = 1 - ConstantA`.
Vector Blend In Place	Computes `ConstantA * A + ConstantB * B` for each pair of vectors in Vector List A and Vector List B, and stores the value in Vector List B. By default this (constants = 1) adds the two vectors. Set `ConstantB = -1` to subtract B from A. You can also use the function to Linear Interpolate, by setting `ConstantB = 1 - ConstantA`.
Scalar Vector Multiply	Computes `Scalar Multiplier * Scalar * Vector` for each scalar/vector pair in the two input lists, and returns the value in a new Vector List.
Scalar Vector Multiply In Place	Computes `Scalar Multiplier * Scalar * Vector` for each scalar/vector pair in the two input lists, and stores the value in the input Vector List.
Constant Vector Multiply	Computes `Constant * Vector` for each element in the Vector List and returns the value in a new list.
Constant Vector Multiply In Place	Computes `Constant * Vector` for each element in Vector List, and stores the value in Vector List.
Vector To Scalar	Converts each Vector in Vector List to a Scalar by computing `ConstantX * Vector.X + ConstantY * Vector.Y + ConstantZ * Vector.Z` , and returns the value in a new Scalar List. You can use it to extract the X, Y, and Z values from a Vector, or other component-wise math.
Scalar Invert	Computes `Numerator / Scalar` for each element of the Scalar List and returns the value in a new Scalar List. If Abs(Scalar) < Epsilon, set to Set On Failure value.
Scalar Invert In Place	Computes `Numerator / Scalar` for each element of the Scalar List and stores the value in input Scalar List. If Abs(Scalar) < Epsilon, set to Set On Failure value.
Scalar Blend	Computes `ConstantA * A + ConstantB * B` for each pair of values in Scalar List A and Scalar List B and returns the value in the new Scalar List. By default this (constants = 1) just adds the two values. Set `ConstantB = -1` to subtract B from A. The function can also be used to Linear Interpolate, by setting `ConstantB = 1 - ConstantA`.
Scalar Blend In Place	Computes `ConstantA * A + ConstantB * B` for each pair of values in ScalarListA and ScalarListB and return in ScalarListB. By default this (constants = 1) just adds the two values. Set `ConstantB = -1` to subtract B from A. Can also be used to Linear Interpolate, by setting `ConstantB = ( 1 - ConstantA )`.
Scalar Multiply	Computes `Scalar Multiplier * A * B` for each pair of values in Scalar List A and Scalar List B, and returns the values in the new Scalar List.
Scalar Multiply In Place	Computes `Scalar Multiplier * A * B` for each pair of values in Scalar List A and Scalar List B, and returns the values in Scalar List B.
Constant Scalar Multiply	Computes `Constant * Scalar` for each value in Scalar List, and returns the values in the new Scalar List.
Constant Scalar Multiply In Place	Computes `Scalar Multiplier A * B` for each pair of values in Scalar List A and Scalar List B, and returns the values in the current Scalar List.

Mesh Sampling

These functions calculate and place points along the surface of a mesh.


Node	Description
Compute Point Sampling	Compute a set of sample points lying on the surface of Target Mesh based on the provided sampling Options. Samples are approximately uniformly distributed, and non-overlapping relative to the provided Options.
Compute NonUniform Point Sampling	Compute a set of sample points lying on the surface of Target Mesh based on the provided sampling Options and NonUniform Options.
Compute Vertex Weighted Point Sampling	Compute a set of sample points lying on the surface of TargetMesh based on the provided sampling Options and NonUniform Options.

Ray

Utility functions for creating and querying rays. A ray is a line which can be used to determine intersections of objects. These are particularly useful for building interactive user interfaces in Blueprints.


Node	Description
Make Ray From Points	Create a ray from two points, placing the origin at A and the direction as Normalize (B-A).
Make Ray From Point Direction	Create a ray from an origin and direction, with optionally non-normalized direction.
Get Transformed Ray	Apply the given transform to the given ray, or optionally the Transform Inverse, and return the new transformed ray.
Get Ray Point	Get a point at the given distance along the Ray, `Origin + Distance * Direction`.
Get Ray Start End	Get two points along the ray.
Get Ray Parameter	Project the given point onto the closest point along the ray, and return the ray parameter and distance at that point.
Get Ray Point Distance	Get the distance from the given point to the closest point on the ray.
Get Ray Closest Point	Get the closest point on the Ray to the given point.
Get Ray Sphere Intersection	Check if the ray intersects a sphere defined by the Sphere Center and Sphere Radius. This function returns two intersection distances (ray parameters). If the ray grazes the sphere, both distances will be the same. If it misses, they will be MAX_FLOAT. Use the function Get Ray Point to convert the distances to points on the ray and sphere.
Get Ray Box Intersection	Check if the ray intersects a sphere defined by the Sphere Center and Sphere Radius.
Get Ray Plane Intersection	Find the intersection of a ray and a plane.
Get Ray Line Closest Point	Compute the pair of closest points on a 3D ray and line. The line is defined by an origin and direction, but extends infinitely in both directions.
Get Ray Segment Closest Point	Compute the pair of closest points on a 3D ray and line segment. The line segment is defined by its two endpoints.

Material ID

Functions for manipulating Material IDs of a mesh. A Material ID is a per-triangle integer and is not directly connected to any specific Material. Each Material ID is associated with a Mesh Section when converting to or from a Static Mesh.


Node Name	Description
Get Has Material IDs	Returns true if the mesh has Material IDs available/enabled.
Enable Material IDs	Enables Material IDs on a mesh, initialize to 0.
Clear Material IDs	Resets all Material IDs on a mesh to 0.
Get Max Material ID	Returns the maximum Material ID currently set on a mesh.
Remap Material IDs	For all triangles with a Material ID matching a given value, and sets the Material ID to a new value.
Set All Triangle Material IDs	Sets the Material ID of all triangles in a mesh to the values in an input Index List.
Set PolyGroup Material ID	Sets the Material ID of all triangles in a mesh that have a specified PolyGroup ID (in a given PolyGroup layer) to the specified Material ID.

Vertex Values

You use these functions to get and manipulate mesh values stored at vertices, including Vertex Colors

Multiple values, such as Normals, can be stored at a given vertex but these methods will only return one.


Node Name	Description
Set Mesh Constant Vertex Color	Sets all vertex colors to a specific color.
Set Mesh Per Vertex Colors	Sets the color for every vertex using a Color List.
Get Mesh Per Vertex Colors	Gets a list of single vertex colors for each mesh vertex in the Target Mesh, derived from the Vertex Color Overlay.
Set Mesh Selection Vertex Color	Sets the colors in the Target Mesh's Vertex Color Overlay, identified by the Selection, to a constant value. For a Vertex Selection, each existing Vertex Color Overlay Element for the vertex is updated. For a Triangle or PolyGroup Selection, all Overlay elements in the identified Triangles are updated. For a Vertex Selection, each existing Vertex Color Overlay Element for the vertex is updated. For a Triangle or PolyGroup Selection, all Overlay elements in the identified Triangles are updated.
Convert Mesh Vertex Colors SRGB To Linear	Apply an SRGB to Linear color transformation on all vertex colors.
Convert Mesh Vertex Colors Linear To SRGB	Apply a Linear to SRGB color transformation on all vertex colors.
Get Mesh Per Vertex Normals	Get a list of single normal vectors for each mesh vertex in the Target Mesh, derived from the Normals Overlay.
Get Mesh Per Vertex UVs	Get a list of single vertex UVs for each mesh vertex in the Target Mesh, derived from the specified UV Overlay.
Blur Mesh Vertex Colors	Blur the color attribute of the mesh. If the mesh has no color attribute, the function returns the mesh unchanged.

Texture Sampling and Creation

Functions for reading and creating texture data.


Node Name	Description
Sample Texture 2D At UV Positions	Sample the given Texture Map at the list of UV positions and return the color at each position in the Color List output.
Create New Texture 2D Asset	Create a serialized Texture 2D Asset from a temporary UTexture2D.
Sample Texture Render Target 2D At UV Positions	Sample the given Texture Map at the list of UV positions and return the color at each position in Color List output. This function fetches GPU data before sampling, so, depending on your application, it can be inefficient and slow.

Baking

These functions bake data between a source and target mesh into texture or vertex color data. You can bake various mesh data such as normals, curvature, ambient occlusion, opacity map, and subsurface color map. There is also the ability to specify type of filtering to apply.


Node Name	Description
Bake Texture	Creates textures for the Target Mesh from data sampled in the Source Mesh.
Bake Vertex	Populates the vertex colors in the Target Mesh with the results of the baking properties of the given Source Mesh.
Bake Texture From Render Captures	Bakes textures for a target mesh from render captures.

UV

You use these functions to manipulate the UVs of a mesh.


Node Name	Description
Get Num UV Channels	Gets the number of UV Channels on a mesh.
Set Num UV Channels	Sets the number of UV Channels on a mesh.
Get UV Set Bounding Box	Gets the 2D bounding box of all UVs in a UV Channel.
Copy UV Channel	Replaces target UV Channel with values from source UV Channel.
Translate Mesh UVs	Applies 2D Translation to all UVs, or a subset of UVs if you provide a Selection, in the UVSet Index.
Scale Mesh UVs	Applies 2D Scale to all UVs, or a subset of UVs if you provide a Selection, in the UVSet Index.
Rotate Mesh UVs	Apples 2D Rotation to all UVs, or a subset of UVs if you provide a Selection, in the UVSet Index.
Recompute Mesh UVs	Recomputes UVs for a Mesh based on different types of well-defined UV islands, such as existing UV islands, PolyGroups, or the Selection input.
Repack Mesh UVs	Packs the existing UV islands into standard UV space.
Set Mesh UVs From Planar Projection	Using Planar projection, set UVs for an entire mesh or a subset you define by the Selection input.
Set Mesh UVs From Box Projection	Using Box Projection, set UVs for an entire mesh or a subset you define by the Selection input.
Set Mesh UVs From Cylinder Projection	Using Cylinder Projection, set UVs for an entire mesh or a subset you define by the Selection input.
Auto Generate Patch Builder Mesh UVs	Computes new UVs using PatchBuilder method, and optionally pack.
Auto Generate X Atlas Mesh UVs	Computes new UVs using XAtlas, and optionally packs.
Get Mesh UVSize Info	Computes information about dimensions and areas for a UV Channel of a Mesh, with an optional mesh selection.
Get Mesh Per Vertex UVs	Gets a list of single vertex UVs for each mesh vertex in the Target Mesh, derived from the specified UV Overlay.
Copy Mesh UV Channel To Mesh	Copies the 2D UVs from the given UV Channel Index in Copy From Mesh to the 3D vertex positions in Copy To UV Mesh. PolyGroup IDs and Material IDs are preserved in the UV Mesh.
Copy Mesh To Mesh UV Channel	Transfers the 3D vertex positions and triangles of Copy From UVMesh to the given UV Channel identified by To UV Channel Index of Copy To Mesh. The 3D positions (X,Y,Z) will be copied as UV positions (X,Y).
Compute Mesh Local UV Param	Compute local UV parameterization on Target Mesh vertices around the given CenterPoint / Triangle. This method uses a Discrete Exponential Map parameterization, which unwraps the mesh locally based on geodesic distances and angles. The Center Point will have a UV value (0,0), and the computed vertex UVs will be such that `Length(UV) == geodesic distance`.

PolyGroup

Functions for manipulating PolyGroups of a mesh. PolyGroups are per-triangle integers that implicitly define regions and patches of triangles in the modeling tools and some Geometry Script operations. However, a PolyGroup layer is ultimately a per-triangle number, and you can use it for any other purpose. To learn more about PolyGroups see, Understanding PolyGroups.


Node Name	Description
Get Has PolyGroups	Returns true if the mesh has a standard PolyGroup Layer.
Enable PolyGroups	Enables standard PolyGroup Layer on a Mesh.
Get Num Extended PolyGroup Layers	Returns the count of extended PolyGroup Layers. Note that extended PolyGroup Layers are not yet fully supported by all operations or modeling tools.
Set Num Extended PolyGroup Layers	Sets the number of extended PolyGroup Layers on a Mesh.
Clear PolyGroups	Resets the triangle PolyGroup assignments to a constant value for a given PolyGroup Layer.
Copy PolyGroups Layer	Copies PolyGroups from one layer to another.
Convert UV Islands To PolyGroups	Creates and assigns a new PolyGroup for each disconnected UV island of a Mesh.
Convert Components To PolyGroups	Creates and assigns a new PolyGroup for each disconnected component of a Mesh.
Compute PolyGroups From Angle Threshold	Sets PolyGroups by partitioning the mesh based on an edge crease/opening-angle.
Compute PolyGroups From Polygon Detection	Identifies polygons and assigns PolyGroup IDs.

Bone Weight

These functions calculate and manipulate bone weights, also known as skin weights. Bone weights determine a bone's transformation influence on a set of vertices. You can also get information about the skeleton stored in the dynamic mesh. This information is one-to-one with the Skeletal Mesh skeleton after you convert to dynamic mesh through the Copy Mesh From Skeletal Mesh node.


Node	Description
Mesh Has Bone Weights	Check whether the Target Tesh has a per-vertex Bone Weight attribute set.
Mesh Create Bone Weights	Create a new Bone Weights attribute on the Target Mesh, if it does not already exist. If it does exist, and `bReplaceExistingProfile` is passed as true, the attribute will be removed and re-added, to reset it.
Get Max Bone Weight Index	Determine the largest Bone Weight index that exists on the mesh.
Get Vertex Bone Weights	Return an array of Bone Weight at a given vertex of the Target Mesh.
Get Largest Vertex Bone Weight	Return the Bone Weight of the maximum weight at a given vertex of the Target Mesh.
Set Vertex Bone Weights	Set the Bone Weight at a given vertex of the Target Mesh.
Set All Vertex Bone Weights	Set all vertices of the Target Mesh to the given Bone Weights.
Compute Smooth Bone Weights	Computes a smooth skin binding for the given mesh to the skeleton provided.
Transfer Bone Weights From Mesh	Transfer the bone weights from the SourceMesh to the TargetMesh. Assumes that the meshes are aligned. Otherwise, use the Transform Mesh geometry script function to align them.
Copy Bones From Mesh	Copy the bone attributes (skeleton) from the Source Mesh to the Target Mesh.
Discard Bones From Mesh	Discard the bone attributes (skeleton) from the Target Mesh.
Get Bone Index	Get the index of the bone with the given name.
Get Root Bone Name	Get the name of the root bone.
Get Bone Children	Get the information about the children of the bone.
Get All Bones Info	Get an array of bones representing the skeleton. Each entry contains information about the bone.
Get Bone Info	Get the index of the bone with the given name.

Mesh Geometric Queries

Functions for high-level geometric queries of a mesh.


Node Name	Description
Get Mesh Bounding Box	Computes the bounding box of the mesh vertices.
Get Mesh Volume Area	Computes the volume and area of the mesh.
Get Is Closed Mesh	Returns true if the mesh is closed, such as no topological boundary edges.
Get Num Open Border Loops	Returns the number of open border loops, such as "holes" in the mesh.
Get Num Open Border Edges	Returns the number of topological boundary edges in the mesh.
Get Num Connected Components	Returns the number of separate connected-components in the mesh, such as "triangle patches" connected by shared edges.
Compute Mesh Convex Hull	Computes the Convex Hull of a given Mesh, or part of the mesh you define by the Selection input, and returns in a separate mesh.
Compute Mesh Swept Hull	Computes a 2D swept-hull of the input mesh and returns in a separate mesh.
Compute Mesh Convex Decomposition	Computes a Convex Hull Decomposition of the given Target Mesh. Assuming more than one hull is requested, multiple hulls will be returned that attempt to approximate the mesh. There is no guarantee that the entire mesh is contained in the hulls.
Get Mesh Volume Area Center	Computes the volume, area, and center-of-mass of the mesh.

Mesh Geodesic

These functions compute the shortest given path on a mesh surface.


Node	Description
Get Shortest Vertex Path	Computes a vertex list that represents the shortest path constrained to travel along mesh triangle edges between the prescribed start and end vertex. This can fail if the Start and End points are within separate connected components of the mesh.
Get Shortest Surface Path	Computes a polypath that represents the shortest mesh surface path between two prescribed points on the provided mesh.This can fail if the Start and End points are within separate connected components of the mesh. Barycentric coordinates are of the form (a,b,c) where each entry is positive and `a + b + c = 1`. If the provided coordinates are invalid, the value (1/3, 1/3, 1/3) is used.
Create Surface Path	Computes a polypath that represents a "straight" surface path starting at the prescribed point on the mesh, and continuing in the indicated direction until reaching the requested path length or encountering a mesh boundary, whichever comes first. Barycentric coordinates are of the form (a,b,c) where each entry is positive and `a + b + c = 1`. If the provided coordinate is invalid, the value (1/3, 1/3, 1/3) is used. Also, if the direction vector is nearly zero, the up-vector is used.

Simple Polygon

A simple 2D polygon is a closed polygon with no holes. You can use these functions to call and manipulate simple polygons.


Node	Description
Get Polygon Vertex Count	Returns the number of vertices in a simple polygon.
Get Polygon Vertex	Returns the specified vertex of a simple polygon. Vertex Index loops around, that is, -1 gives the last vertex in the polygon. If the polygon has no vertices, it returns the zero vector.
Set Polygon Vertex	Set the specified vertex of a simple polygon. Vertex Index loops around, that is, -1 gives the last vertex in the polygon. Does nothing if the polygon has no vertices.
Add Polygon Vertex	Set the specified vertex of a simple polygon. Returns the index of the added vertex.
Get Polygon Tangent	Returns a vertex's tangent of a simple polygon. Vertex Index loops around, that is, -1 gives the tangent of the last vertex in the polygon. If the polygon has no vertices, it returns the zero vector.
Get Polygon Arc Length	Returns the arc length of a simple polygon.
Get Polygon Area	Returns the area enclosed by a simple polygon.
Get Polygon Bounds	Returns the bounding box of a simple polygon.
Convert Spline To Polygon	Sample positions from a `USplineComponent`. into a simple polygon, based on the given Sampling Options.
Simple Polygon To Array Of Vector	Returns an array of 3D vectors with the polygon vertex locations, with Z coordinate set to zero.
Simple Polygon To Array Of Vector2D	Returns an array of 2D vectors with the polygon vertex locations.
Array Of Vector To Simple Polygon	Returns a polygon created from an array of 3D position vectors, ignoring the Z coordinate.
Array Of Vector2D To Simple Polygon	Returns a polygon created from an array of 2D position vectors.

Polygon List

A polygon list includes a list of general polygons, which may have holes. You can use these functions to call and edit polygons in a polygon list.


Node	Description
Get Polygon Vertex Count	Returns the number of vertices in a polygon's outer shape, if Hole Index is -1, or in the specified inner hole. Returns 0 for invalid polygon or hole indices.
Get Polygon Vertex	Returns the specified vertex of a polygon — either of the outer polygon, if Hole Index is -1, or specified inner hole.Vertex are the zero vector for invalid polygon or hole indices, or if the polygon is empty. Vertex Index will loop.
Get Polygon Count	Returns the number of polygons in the Polygon List.
Get Polygon Hole Count	Returns the number of holes in a polygon. Returns zero for an invalid Polygon Index.
Get Polygon Vertices	Returns the vertices of a polygon — either of the outer polygon, if Hole Index is -1, or specified inner hole. Out Vertices are empty for invalid polygon or hole indices.
Get Polygon Area	Returns the area enclosed by a polygon. Returns zero for an invalid Polygon Index.
Get Polygon Bounds	Returns the bounding box of a polygon. Returns an empty, invalid box for an invalid Polygon Index.
Get Simple Polygon	Returns a specified simple polygon from a polygon list — either the outer polygon, if Hole Index is -1, or specified inner hole. Polygon are empty for invalid polygon or hole indices.
Get Polygon List Area	Returns the area enclosed by a polygon.
Get Polygon List Bounds	Returns the bounding box of a polygon.
Create Polygon List From Single Polygon	Create a polygon list of a single polygon, with optional holes.
Add Polygon To List	Add Polygon to a polygon list, with optional holes. Returns index of the added polygon.
Create Polygon List From Simple Polygons	Create a Polygon List from an array of Simple Polygons.
Append Polygon List	Add the polygons in Polygons to Append to Polygon List.
Polygons Union	Compute union of all polygons in Polygon List. Also resolves self-intersections within each polygon.
Polygons Difference	Compute difference of Polygon List and Polygons to Subtract.
Polygons Intersection	Compute intersection of Polygon List and Polygons to Intersect.
Polygons Exclusive Or	Compute exclusive or of Polygon List and Polygons to Exclusive Or.
Polygons Offset	Apply a single offset to a list of closed polygons.
Polygons Offsets	Apply two offsets in sequence to a list of closed polygons.
Polygons Morphology Open	Apply a morphological open operator to a list of closed polygons — first offsetting by -Offset, then by +Offset. If Offset is negative, this instead functions as a close operation.
Polygons Morphology Close	Apply a morphological close operator to a list of closed polygons — first offsetting by +Offset, then by -Offset. If Offset is negative, this instead functions as an open operation.
Create Polygons From Path Offset	Apply an offset to a single open 2D path, generating closed polygons as a result.

Poly Path

These functions perform poly path manipulations. A poly path is a path defined by an ordering of vertices.


Node Name	Description
Get Poly Path Num Vertices	Returns the number of vertices in the poly path
Get Poly Path Last Index	Returns the index of the last vertex in the poly path.
Get Poly Path Vertex	Returns the 3D location of the specified vertex.
Get Poly Path Tangent	Returns the local tangent vector of the poly path at the specified vertex index.
Get Poly Path Arc Length	Returns the length of the poly path.
Get Nearest Vertex Index	Returns the index of the nearest poly path vertex to the specified point in 3D.
Flatten To 2D On Axis	Creates a 2D flatten copy of the path, by dropping the given axis and using the other two coordinates as the new X, Y coordinates.
Convert Spline To Poly Path	Samples the positions from a USplineComponent into a Poly Path, based on the given Sampling Options.
Convert Poly Path To Array	Populates an array of 3D vectors with the poly path vertex locations.
Convert Array To Poly Path	Creates a poly path from an array of 3D position vectors.
Convert Poly Path To Array Of Vector 2D	Creates an array of 2D Vectors with the poly path vertex locations projected onto the XY plane.
Convert Array Of Vector 2D To Poly Path	Creates a poly path from an array of 2D position vectors. The Z-coordinate of the corresponding Poly Path vertices is zero.
Create Circle Path 3D	Creates a closed circle around the origin on the XY plane, then is repositioned by the Transform input.
Create Circle Path 2D	Creates a closed circle on the XY plane around the given Center. For closed paths, the end vertex is not a duplicate of the start vertex.
Create Arc Path 3D	Creates an open arc around the origin on the XY plane, then is repositioned by the Transform input.
Create Arc Path 2D	Creates an open arc on the XY plane around the given Center.

Mesh Comparisons

Functions for comparing two meshes. These nodes do not modify either mesh through their usage.


Node Name	Description
Is Same Mesh As	Returns true if the two input meshes are equivalent under the comparisons defined by the input options.
Measure Distances Between Meshes	Measures the min/max and average closest-point distances between two meshes.
Is Intersecting Mesh	Returns true if the two input meshes (with optional transforms) are geometrically intersecting.

BVH & Spatial Queries

These functions create and query a Bounding Volume Hierarchy (BVH) object for a mesh.


Node Name	Description
Build BVH For Mesh	Builds a BVH object for a mesh that can be used by Is BVH Valid For Mesh, Rebuild BVH for Mesh, Find Nearest Point On Mesh, Find Nearest Ray Intersection With Mesh, and Is Point Inside Mesh nodes. The function returns a Geometry Script dynamic mesh BVH struct.
Is BVH Valid For Mesh	Checks if the BVH object can still be used with the Mesh — it generally returns false if the mesh has been changed.
Rebuild BVH For Mesh	Rebuilds the BVH object for the mesh in-place, which can reduce memory allocations, compared to building a new BVH.
Find Nearest Point On Mesh	Finds the nearest point on the mesh/BVH to a given 3D point.
Find Nearest Ray Intersection With Mesh	Finds the nearest intersection of a 3D ray with the mesh or BVH.
Is Point Inside Mesh	Tests if a point is inside the mesh/BVH using the Fast Winding Number query.

Utilities

These helper functions are useful in Geometry Script mesh processing and procedural generators.


Node Name	Description
Create Dynamic Mesh Pool	Creates a new dynamic mesh pool object.
Create Unique New Asset Path Name	Create a new unique asset name given a base path and base asset name, which is useful with functions such as Create New Static Mesh Asset From Mesh. This node only works in the Editor.
Get Mesh Info String	Returns a debug string that contains mesh statistics and other information.
Sample Spline To Transforms	Sample a USplineComponent into a list of FTransforms, based on the given Sampling Options.

Glossary


Term	Definition
Overlay	A data structure representing a type of vertex data applied to a mesh.These types include: vertex color, normal, tangent, and UV. Multiple values of the specified type can be stored at a single vertex. In such cases, depending on the type, one of the following occurs: the last value is used, the values are averaged, or an arbitrary value is used.
One-ring	The neighboring vertices of the selected vertex, connected by an edge. The one-ring of vertex M.
UV Set	Contains the UV coordinates of a mesh, also referred to as the UV Channel. You can use multiple UV Channels to represent different UV maps.
Extents	The half-dimensions of a box, measured along the three axes. They are used to determine how much to extend from a center point. A center point, C, and Extent, E, results in a box with a bottom-left-near corner at `C - E` and a top-right-far corner at `C + E`.