Hello...
So I've been bashing my head around this... It started initially with the phoenix fd liquid simulator..I thought that is the culprit, then I exported the mesh to Alembic, then I thought that is the problem + many other things until I ended up with this simple setup- a collapsed mesh(Singe sided!) from the ABC file and a simple plane and a ground plane.
I have a ground plane at -60meters. And I have this water plane(with the cutout) and the ,abc mesh at +3 meters. I don't know how to explain it properly, I think the images shows the issue. If the meshes are separate they render differently, if they are attached they render uniform and with correct depth/absorbtion parameter.
Is there anyway around this? In case you are wondering why I need this, I want to render a big plane with displacement with water and then composit the phoenix fd simulator box on top of it, but I can't do that because of this problem. I've attached another screenshot to see. Look how the displaced mesh (a collapsed edit poly now) looks. This doesn't seem right at all to me.
Even more weird, if I attached the mesh to the plane with the cut, it renders correct!!!
Thanks in advance!