Geometry Script Reference

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

The Geometry Script 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 Script 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.

Primitive Generation

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

Node Name

Description

Append Box

Appends a 3D box to a specified Dynamic Mesh.

Append Sphere Lat Long

Appends a 3D Sphere triangulated using latitude/longitude topology to a Dynamic Mesh.

Append Sphere Box

Appends a 3D sphere triangulated using box topology to a Dynamic Mesh.

Append Capsule

Appends a 3D Capsule to a Dynamic Mesh.

Append Cylinder

Appends a 3D Cylinder (with optional end caps) to a Dynamic Mesh.

Append Cone

Appends a 3D cone to a Dynamic Mesh.

Append Torus

Appends a 3D torus (donut) or partial torus to a Dynamic Mesh.

Append Rectangle

Appends a planar Rectangle to a Dynamic Mesh.

Append Round Rectangle

Appends a planar Rectangle with Rounded Corners (RoundRect) to a Dynamic Mesh.

Append Disc

Appends a planar disc to a Dynamic Mesh.

Append Triangulated Polygon

Appends a Delaunay triangulation of a planar 2D polygon to a Dynamic Mesh.

Append Revolve Polygon

Appends 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

Appends a linear staircase using a selected Dynamic Mesh.

Append Curved Stairs

Appends a rising circular staircase using a selected Dynamic Mesh.

Append Mesh Transformed

Applies each transform to Append Mesh and 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.

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/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.

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

Appends the geometry from one mesh to another, with optional Transform.

Append Mesh Repeated

Appends 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 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.

Get Mesh Selection Info

Queries information about a Mesh Selection.

Debug Print Mesh Selection

Prints information about the Mesh Selection to the Output Log.

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 selection 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

Set 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 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 Target Mesh identified by the Selection, or all faces if the 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 Functions

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

Node Name

Description

Apply Recursive PNTessellation

Apply PN (Point-Normal) Tessellation to the input mesh using a recursive strategy, that is, 1-to-4 triangle splits.

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 PNTesselation

Applies PN Tessellation to the input mesh.

Apply Uniform Tessellation

Applies uniform tessellation to the input mesh.

Simplification Functions

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.

Normals Functions

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 Per Face 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).

Cleanup/Repair Functions

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 TrianglePositions

Returns the three corner positions for a Triangle.

Get TriangleFace Normal

Returns the face/facet normal of a Triangle.

Get TriangleUVs

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..

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.

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 + Constant B * 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 Constant B = ( 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.

MaterialID Functions

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 values 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.

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.

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, and ambient occlusion.

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.

UV Functions

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

Node Name

Description

Get Num UV Sets

Gets the number of UV Layers on a Mesh.

Set Num UV Sets

Sets the number of UV Layers on a Mesh.

Get UV Set Bounding Box

Gets the 2D bounding box of all UVs in a UV Set.

CopyUVSet

Replaces target UV set with values from source UV set.

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 UVSet 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 TargetMesh, derived from the specified UV Overlay.

Copy Mesh UV Layer To Mesh

Copies the 2D UVs from the given UVSet 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 Layer

Transfers the 3D vertex positions and triangles of Copy From UVMesh to the given UV Layer identified by To UV Set Index of Copy To Mesh. The 3D positions (X,Y,Z) will be copied as UV positions (X,Y).

PolyGroup Functions

Functions for manipulating PolyGroups of a mesh. PolyGroups are per-triangle integers that implicitly define regions and patches of triangles in 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.

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.

GetNum 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.

Mesh Geometric Queries

These functions allow 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.

PolyPath

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

Node Name

Description

Get Poly Path Num Vertices

Returns the number of vertices in the PolyPath

Get Poly Path Last Index

Returns the index of the last vertex in the PolyPath.

Get Poly Path Vertex

Returns the 3D location of the specified vertex.

Get Poly Path Tangent

Returns the local tangent vector of the PolyPath at the specified vertex index.

Get PolyPath Arc Length

Returns the length of the PolyPath.

Get NearestVertexIndex

Returns the index of the nearest PolyPath 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 PolyPath

Samples the positions from a USplineComponent into a PolyPath, based on the given Sampling Options.

Convert PolyPath To Array

Populates an array of 3D vectors with the PolyPath vertex locations.

Convert Array To PolyPath

Creates a PolyPath from an array of 3D position vectors.

Convert PolyPath To Array Of Vector 2D

Creates an array of 2D Vectors with the PolyPath vertex locations projected onto the XY plane.

Convert Array Of Vector 2D To PolyPath

Creates a PolyPath from an array of 2D position vectors. The Z-coordinate of the corresponding PolyPath vertices will be 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

These functions enable comparisons between 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/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 like 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.

One-ring Triangles

The one-ring of vertex M.

UV Set/Layer

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.