Ignore displacement on no visible mesh ?

[bigbossfr]

Hi,
I have a problem : i have a mesh shattered with DMM. Like you know, there are faces into the DDM mesh (because is shattered). I apply a displacement. It is very very very slow to render.
It looks like Vray apply a displacement "into" the mesh (all faces into the mesh). So it is impossible to render.

What is the solution ?
Is it not possible to add an option on the VrayDisplacement to create displace/subdivise the mesh just on "visible faces" (visible from the camera) ? Or "exterior faces" ?

Thank you.

[bigbossfr]

Hi,
The problem is "general" with another setup, with displacement in projection.
We have a plane, with a checker projected in displacement on this plane :





Result : 59 sc

I scale the plane :



Result : 1 min 15

We are working on a feature film, with ocean. With projection, we jump from 10 min to 1h to render...

Is it possible to have an option to disable the displacement on meshs (and the same mesh) which are not on the screen space ? Or visible ? (mesh behind another mesh)

Ps : and why the displacement is not the same ? It is view dependent.

Thank you.

[vlado]

Can you post your scenes here (I know they are really simple, but there may be other things going on).

Anyways, it might help to disable the "Tight bounds" option for displacement. That way, V-Ray won't sample the displacement until it really needs it.

Best regards,
Vlado

[bigbossfr]

Here a scene.
Scale the pPlane1 to something like 20, and after 500.
1) The render time will be slow with 500
2) The image will not be the same

It will be great if Vray doesn't subdivide (or displace) with an option, the mesh outside the screen space.
The "Tight bounds" is disabled.

Thanks Vlado