Visual Dataprep Operation Reference

Details on the operations you can apply to selected scene elements in the Visual Dataprep system.

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This page describes each of the Operations blocks that you can use in the Visual Dataprep system to modify your Assets and scene elements.

Each type of Operations block encapsulates a specific kind of modification that the Unreal Editor can make to 3D data. When the Visual Dataprep system carries out each action in your Dataprep graph, it performs each operation you've defined in that action on all the Assets or Actors that match the criteria set by the Select By blocks above it. For more background information, see the Visual Dataprep Overview .

On Actor

On Actor operations apply only to Actors that match the Select By criteria you set up for their steps. That means only items that you see listed in the World Outliner Preview panel on the right of the Dataprep preview UI. If your Select By criteria match other scene elements, like the Texture, Material, and Static Mesh Assets that are listed in the Content Browser Preview panel on the left of the Dataprep preview UI, the On Actor operation will have no effect on those elements.

Compact Scene Graph

For each Static Mesh Actor that matches the Select By criteria you set up for this step, this operation deletes the Actor if it doesn't have any visual result on the scene, and if none of its descendants in the scene hierarchy have visual results on the scene. The effect is to tidy unnecessary elements from the scene hierarchy without compromising the visual objects in the scene.

Compact Scene Graph

Create Proxy Mesh

This operation collects the geometry from all Static Mesh Actors that matches the Select By criteria you set up for this step, and merges the geometry into a single new mesh using the Proxy Geometry Tool .

Create Proxy Mesh

Setting

Description

New Actor Label

Specifies the name of the new Actor created from the merged geometry.

Quality

The level of quality for the geometry of the generated proxy mesh. Lower values are less detailed but may render more efficiently. Higher values are more detailed and faithful to the original geometry, but may not be as efficient to render.

Merge

This operation collects the geometry from all Static Mesh Actors that matches the Select By criteria you set up for this step, and merges the geometry into a single new mesh.

Merge

Setting

Description

New Actor Label

Specifies the name of the new Actor created from the merged geometry.

Pivot Point at Zero

Enable this setting if you want the merged mesh to have its pivot point set at the world origin. If left disabled, the pivot will be located at the first merged component.

Set Mesh

For each Static Mesh Actor that matches the Select By criteria you set up for this step, this operation changes all Static Mesh Assets referred to by the Actor to a different Static Mesh Asset that you specify in the settings.

Set Mesh

Setting

Description

Static Mesh

The Static Mesh Asset that you want the Actor to instance in place of its existing Static Mesh. This replacement may be any Static Mesh in the Content Browser Preview panel of the Dataprep Editor, or any Static Mesh Asset that already exists in your project.

This operation has no effect on Actors that don't already refer to a Static Mesh Asset. For example, if you have an empty Actor in the scene hierarchy that doesn't already have a Static Mesh, you won't be able to use this operation to add a new Static Mesh to that Actor.

Set Mobility

For each Actor that matches the Select By criteria you set up for this step, this operation sets the value of the Actor's Mobility setting.

The Mobility setting has slightly different implications for Light Actors than it does for Static Mesh Actors. For details on how it is interpreted, see Actor Mobility .

Set Mobility

Setting

Description

Mobility Type

The value you want to set for the Actor's Mobility setting.

Find the Mobility setting in the Details panel:

Actor Mobility

On Mesh

On Mesh operations apply only to Static Mesh Assets.

  • If your Select By criteria match any Static Mesh Assets that you see listed under the Geometries folder in the Content Browser Preview panel, the operation will apply to those Assets.

  • If your Select By criteria match any Actors in the World Outliner Preview that refer to Static Mesh Assets, the operation will also apply to those Static Mesh Assets.

  • If your Select By criteria match any other kinds of scene elements, like Actors, Textures, or Materials, the On Mesh operation will have no effect on those elements.

Datasmith Tessellation

For each Static Mesh that matches the Select By criteria you set up for this step, if that mesh was originally tessellated from a parametric surface, this operation re-tessellates the mesh geometry with new settings.

Datasmith Tessellation

Setting

Description

Chord Tolerance

The maximum distance between any generated triangle and the original surface.

Max Edge Length

The maximum length of any edge in the generated triangles.

Normal Tolerance

The maximum angle between adjacent triangles.

Setting smaller values typically results in creating more triangles. For details on how these parameters are interpreted, see Using Datasmith with CAD File Formats .

Generate Unwrapped UVs

For each Static Mesh that matches the Select By criteria you set up for this step, this operation unwraps the mesh geometry into a 2D UV map and saves the mapping in the specified UV channel on the Static Mesh Asset.

Generate Unwrapped UVs

Setting

Description

Channel Selection

Determines what UV channel the generated UV mapping is saved to. First Empty Channel saves the unwrapped UV in the first empty UV channel. Specify Channel saves the unwrapped UV in the channel identified by the UV Channel setting.

UV Channel

When Channel Selection is set to Specify Channel, use this setting to determine the index of the UV channel that the unwrapped UV is saved to.

Angle Threshold

Determines the maximum angle between two adjacent faces for those faces to remain connected after unwrapping. Raising this value minimizes the number of separate UV "islands", keeping more triangles connected to their neighbors and reducing the number of seams that may cause breaks in texture mapping. However, this may also introduce more distortion in the wrapped textures, as triangles may need to be more aggressively resized in 2D space in order to remain connected to their neighbors.

Set Convex Collision

For each Static Mesh that matches the Select By criteria you set up for this step, this operation replaces the Static Mesh's collision with a new convex decomposition made up of multiple volumes, or hulls.

Set Convex Collision

Setting

Description

Hull Count

The maximum number of convex volumes to create.

Max Hull Verts

The maximum number of vertices that are allowed for any generated convex hull.

Hull Precision

The number of voxels to use when generating the collision volumes.

Set LOD Group

For each Static Mesh that matches the Select By criteria you set up for this step, this operation replaces the existing LODs for the Static Mesh with new ones that are based on the settings for the group you specify.

These LOD groups are the same ones you can set when you enable automatic LOD generation in the Static Mesh Editor UI. For more information, see Setting Up Automatic LOD Generation .

Set LOD Group

Setting

Description

LOGGroupName

The name of the LOD group that defines the settings you want to use for this Static Mesh.

Set LODs

For each Static Mesh that matches the Select By criteria you set up for this step, this operation replaces the existing LODs for the Static Mesh with new ones that are based on the reduction settings you specify.

These reduction settings are the same ones you can set when you enable automatic LOD generation in the Static Mesh Editor UI. For more information, see Setting Up Automatic LOD Generation .

Set LODs

Setting

Description

Auto Screen Size

When enabled, the screen sizes at which LODs swap are automatically computed.

Reduction Settings

An array of reduction settings that defines how many Levels of Detail to create, and the percentage of triangles each should contain.

Set Simple Collision

For each Static Mesh that matches the Select By criteria you set up for this step, this operation replaces the existing collisions for the Static Mesh with a simple collision volume of the shape you specify.

Set Simple Collision

Setting

Description

Shape Type

Defines the shape of the collision volume that you want to set for the Static Mesh.

Setup Static Lighting

For each Static Mesh that matches the Select By criteria you set up for this step, this operation sets up options that control how the Static Mesh interacts with baked lighting.

Setup Static Lighting

Setting

Description

Enable Lightmap UV Generation

When enabled, the operation generates lightmap UVs for the Static Mesh.

Resolution Ideal Ratio

A ratio between the scale of the Static Mesh geometry and the lightmap resolution to use for the Static Mesh. Raise this value to make your objects use higher resolution lightmaps. This may increase the quality of baked lighting, but also increases memory requirements.

On Object

On Object operations apply to potentially any kind of scene element matched by your Select By criteria.

Delete Objects

This operation deletes all objects that match the Select By criteria you set up for this step.

Delete Objects

Delete Unused Assets

This operation deletes all Assets that match the Select By criteria you set up for this step and that aren't referenced by any other Assets or Actors.

Delete Unused Assets

Set Material

For each Static Mesh or Static Mesh Actor that matches the Select By criteria you set up for this step, this operation replaces all existing Materials with the Material you specify.

Set Material

Setting

Description

Material

The Material you want to use as a substitute for all existing Materials.

Substitute Material

For each Static Mesh or Static Mesh Actor that matches the Select By criteria you set up for this step, this operation replaces any Material that matches the criteria with the substitute Material you specify.

Substitute Material

Setting

Description

Material Search

The name or partial name of the Material or Materials you want to replace.

String Match

Defines the type of matching that you want to perform on the Material Search string. These options are interpreted the same way as when you use a string filter in a Select By block. For details, see the Visual Dataprep Selection Reference .

Material Substitute

The Material you want to use as a substitute for the Materials that match the criteria above.

Substitute Material By Table

For each Static Mesh or Static Mesh Actor that matches the Select By criteria you set up for this step, this operation replaces Materials according to a substitution table that you provide in a DataTable Asset.

Substitute Material By Table

Setting

Description

Material Data Table

The Data Table Asset that determines what Materials are replaced by what other Materials.

The Data Table that you provide in the Material Data Table setting must use the MaterialSubstitutionDataTable row structure. You typically set this row format in the Pick Row Structure dialog box at the time you create your Data Table Asset. For example:

Select the MaterialSubstitutionDataTable Row Structure

With this row structure, each row in the Data Table defines one Material substitution operation that will be executed on each of the Static Mesh Actors and Assets.

  • The first value in the row, Row Name, provides a name for the substitution. You can set this value freely.

  • The second value, Search String, is the name or partial name of the Material or Materials you want to replace in this operation.

  • The third value, String Match, is the type of string comparison you want to make between the Materials in the Static Mesh Assets and Actors and the search string you set in the second value of this row. You can use any of the values accepted by the Substitute Material operation: Exact Match, Contains, or Matches Wildcard. These options are interpreted the same way as when you use a string filter in a Select By block. For details, see the Visual Dataprep Selection Reference .

  • The fourth value, Material Replacement, is the full name of the Material Asset you want to use to replace any Materials that match the search string.

    You can get this value by right-clicking a Material in the Content Browser and selecting Copy Reference from the contextual menu.

For example:

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