Some object is rendered improperly (flickering) from terrain to the sky

[Alexlau1994]

Describe the bug
When I try to put some object (maybe more than 10 of the same object, like trees or rocks, with vegetation brush or just with entity) to the scene, some of object is rendered improperly (flickering) from terrain to the sky.

This problem happens for some of 3d models, example:
Tree06.zip

Steps to reproduce
put the objects to the scene with brush or entity.

Expected behavior
Please provide a concise description of what you expected to happen.

Screenshots/Logs

Lumberyard version
v1.27.0.0

[AMZN-alexpete]

Hi @Alexlau1994 , I think there is something wrong with this model and geometry instancing. If you set r_geominstancing 0 the problem seems to go away, alternately, you can set r_geominstancingthreshold to a higher value like 100, but really what you want to do is use instanced geometry to maximize rendering efficiency.

I'm seeing this warning in the material editor that I think is related. You may need to update your mesh to not have 2 uv sets
[Warning] (Material Editor) - Material 'objects/tree06/tree6' sub-material 2 with 1 uv set(s) was assigned to mesh 'objects/tree06/tree6.cgf' with 2 uv set(s). If you do not intend to use 2 uv sets, remove the extra uv set(s) from the source mesh during the import process. Otherwise, consider checking the desired 'Use uv set 2 for...' shader gen params in the material editor.