Sample Mesh

Menu Path: Operator > Sampling > Sample Mesh

Use the Sample Mesh Operator to get the vertex data of a mesh.

Operator settings

Property Type Description
Output Enum (Inspector) Select the vertex attributes to read from the vertex.
Mode Enum The wrap mode to use for the sequence. The options are:
• Clamp: Clamps the index between the first and last vertices.
• Wrap: Wraps the index around to the other side of the vertex list.
• Mirror: Mirrors the vertex list so out of range indices move back and forth through the list.
Placement mode Enum Specify which primitive part of the mesh to sample from:
• Vertex: Samples positions from all listed vertices.
• Edge: Samples from an interpolation between two consecutives vertices that are part of a triangle on the mesh.
• Surface: Samples from an interpolation between three vertices that define a triangle on the mesh.
Surface coordinates Enum Specify the method this Block uses to sample the surface of a triangle.
• Barycentric: Samples the surface using raw barycentric coordinates. With this method, sampled positions are not constrained by the triangle edges which is useful if you have baked a position outside of the Visual Effect Graph.
• Uniform: Samples the surface uniformly within the triangle area.
This property only appears if you set Placement mode to Surface and Spawn Mode to Custom.
Skinned Transform Enum Specify the transform to apply to the sample from the Skinned Mesh Renderer.
• None: Apply no transform. The sample is the raw value from the geometry buffer of the Skinned Mesh Renderer.
• Apply Local Root Transform: Apply the transform of the root bone relative to the Skinned Mesh Renderer.
• Apply World Root Transform: Apply the world transform of the root bone.
This property only appears if you set Source to Skinned Mesh Renderer.
Source Enum (Inspector) Specify the kind of geometry to sample from. The options are:
• Mesh: Samples from a mesh asset. The Operator becomes a Sample Mesh Operator.
• Skinned Mesh Renderer: Samples from a Skinned Mesh Renderer. The Operator becomes a Sample Skinned Mesh Operator.

Operator properties

Input Type Description
Mesh Mesh The source mesh asset to sample.

This property only appears if you set Source to Mesh
Skinned Mesh Renderer Skinned Mesh Renderer The source Skinned Mesh Renderer component to sample. This is a reference to a component within the scene. To assign a Skinned Mesh Renderer to this port, create a Skinned Mesh Renderer property in the Blackboard and expose it.

This property only appears if you set Source to Skinned Mesh Renderer.
Vertex uint The index of the vertex to sample.

This property only appears if you set Placement mode to Vertex.
Index uint The start index of the edge to sample from. The Block uses this index and the following index to select the line to sample from.
This property only appears if you set Placement mode to Edge and Spawn Mode to Custom.
Triangle uint The index of triangle to sample, assuming the index buffer contains a triangle list.
This property only appears if you set Placement mode to Surface, Spawn Mode to Custom, and Spawn Mode to Custom.
Edge float The interpolation value the Block uses to sample along the edge. This is the percentage along the edge, from start position to end position, that the sample position is taken.
This property only appears if you set Placement mode to Edge and Spawn Mode to Custom.
Barycentric Vector2 The raw barycentric coordinate to sample from the triangle at. The input is two-dimensional (X and Y) and the block calculates the Z value with the values you input: Z = 1 - X - Y. This sampling method does not constrain the sampled position inside the triangle edges.
This property only appears if you set Placement mode to Surface, Surface coordinates to Barycentric, and Spawn Mode to Custom.
Square Vector2 The uniform coordinate to sample the triangle at. The Block takes this value and maps it from a square coordinate to triangle space. To do this, it uses the method outlined in the paper A Low-Distortion Map Between Triangle and Square (Heitz 2019).
This property only appears if you set Placement mode to Surface, Surface coordinates to Uniform, and Spawn Mode to Custom.
Transform Transform The transform to apply after sampling. If you set Source to Skinned Mesh Renderer and Skinned Transfrom to a setting other than None, Visual Effect Graph applies the transform after the root bone transform. If you set Skinned Transform to Apply World Root Transform, the Visual Effect Graph converts the transform to world space.
Output Type Description
Position Position The position attribute of the vertex. This property only appears if you select Position in Output.
Normal Direction The normalized normal attribute of the vertex. This property only appears if you select Normal in Output.
Tangent Vector The x, y, and z components of the tangent attribute of the vertex. This property only appears if you select Tangent in Output.
Bitangent Vector The cross product of Normal and Tangent, multiplied by Bitangent Sign. This property only appears if you select Bitangent in Output
Bitangent Sign Float The w component of the tangent attribute of the vertex. This property only appears if you select Bitangent Sign in Output.
Color Vector4 The color attribute of the vertex. This property only appears if you select Color in Output.
Tex Coord0-7 Vector4 The vertex attribute TexCoord 0 to 7. For unspecified dimensions, this is 0. This property only appears if you select TexCoord0-7 in Output.
Blend Weight Vector4 The bone blend weight attribute of the vertex. This property only appears if you select BlendWeight in Output.
Blend Indices Vector4 The bone indices attribute of the vertex. This property only appears if you select BlendIndices in Output.
Transform Transform The orthonormal basis, where the three vectors are perpendicular to each other and normalized. Visual Effect Graph calculates Transform using Normal, Tangent and Position. This property only appears if you select Transform in Output.
Previous Position Position The position of the vertex from the previous frame. To make this value more accurate, Visual Effect Graph considers the root transform of the previous frame. This property only appears if you select Previous Position in Output.
Previous Normal Direction The normalized normal of the vertex from the previous frame. To make this value more accurate, Visual Effect Graph considers the root transform of the previous frame. You must enable SkinnedMeshRenderer.skinnedMotionVectors or Visual Effect Graph falls back to the current frame. This property only appears if you select Previous Normal in Output.
Previous Tangent Vector The x, y, and z components of the tangent of the vertex from the previous frame. To make this value more accurate, Visual Effect Graph considers the root transform of the previous frame. You must enable SkinnedMeshRenderer.skinnedMotionVectors or Visual Effect Graph falls back to the current frame. This property only appears if you select Previous Tangent in Output.
Previous Bitangent Vector The cross product of Normal and Tangent, multiplied by Bitangent Sign, from the previous frame. You must enable SkinnedMeshRenderer.skinnedMotionVectors or Visual Effect Graph falls back to the current frame. This property only appears if you select Previous Bitangent in Output.
Velocity Vector The difference between Position and Previous Position, divided by Time.deltaTime. This property only appears if you select Velocity in Output.
Previous Transform Transform The orthonormal basis, where the three vectors are perpendicular to each other and normalized. Visual Effect Graph calculates Transform using Previous Normal, Previous Tangent and Previous Position. This property only appears if you select Transform in Output.

Limitations

The Mesh sampling feature has the following limitations:

Reference list

  • Heitz, Eric. 2019. "A Low-Distortion Map Between Triangle and Square". hal-02073696v2