keywords: Houdini, Vertex Animation Textures

Tutorials

Crowds

Vertex Animation Textures for Crowds
https://www.youtube.com/watch?v=StGJ1l8noNs

Issues

Unreal material editor cache issue

If duplicate a material that contains vertex animation and change the texture parameters, you need to restart Unreal editor to refresh the vertex animation, otherwise there’re some issues on playing animation.

Rigid-Body Dynamics (Rigid) mode expects the point attributes “pivot” and “orient”

Error on rendering:

Error: Rigid-Body Dynamics (Rigid) mode expects the point attributes "pivot" and "orient" on packed points but at least one of them is not found on the input geometry..

Solution:
Set Transfer Attributes as orient pivot in Output panel if using RBD Bullet Solver.

Can’t play vertex animation when baking with a large velocity.

If baking vertex animation texture with a large velocity:

vertex animation may not work in Unreal Engine, this may be an issue of Houdini.

Solution:
Bake animation twice: one with low velocity, another one with high velocity. Then import the FBX of low velocity and the textures (position, rotation) of high velocity into engine.

VAT baking output invalid textures and geometry

Caused by:

Solution:
Place DOP Network under Geometry node.

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