Get skinned mesh's previous frame vertex position in Shader

Graphics Shaders & Materials
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1

Hi all, our team needs to generate motion vector in UV space for skinned mesh renderer, but we can’t successfully get the previous frame’s vertex position in shader.

We are using SRP in Unity 2018.4. When we draw the motion vector, we set RendererConfiguration to PerObjectMotionVectors. However, the previous frame’s vertices are not set in TEXCOORD4 and there is document about how we can use PerObjectMotionVectors.

Get access to SkinnedMeshRenderers prev-vert-pos?
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You ever figure this out? I’m having the same issue TEXCOORD4 isn’t set to anything valid in a custom SRP.
Unity 2020.3.11

3

Here is the answer to this old Question: Get access to SkinnedMeshRenderers prev-vert-pos? - Unity Engine - Unity Discussions

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We asked Unity support, their answer is Unity 2018 SRP doesn’t support skinned mesh motion vector (even tho there is a button clearly saying skinnedMotionVectors in SkinnedMeshRenderer component, sucks)

We opt in developing our own SkinnedMesh using Compute Shader and do all thing in GPU side