Speedtree wind problem under Scriptalbe Render Pipeline

Hi there,

We are developing our own scriptable render pipeline recently. When upgrading our legacy shaders to new render pipeline shaders, we have some problems with speed tree wind.

We use Speedtree as our vegetation creator. In our own SRP, we have a new shader for Speedtree. The vertex shader remains the same as the legacy one to make the wind work correctly and the fragment shader was changed to fit our lighting system. But under SRP the wind doesn't seem to work as expected. The speedtree models painted on the terrain seems to be correctly animated by the wind zone. But the speedtrees directly put in the scene are not affected by the wind at all. I test the speedtree assets under LWRP, and the problem remains.

The speedtree vegetations are crucial for our project. Replace the speedtree with HDRP like vegetation is not allowed because of the time limit of our project. So is there any way to make the speedtree wind work correctly under SRP?

Regards