Region rendering - moving region

[tomtnt]

Hi. Is there any way to render moving region? I have one wrong object in my animation but a camera is moving and practically I can't render region render just for that object, because I would have to move that region render every frame. Any chance?

[mikegentile]

a trick that is use is aligning and linking a matte object plane to the camera. make a hole in it. then animate the vertices of the whole. this should render really quick and fix the problem.
hope this helps.

[tomtnt]

Do you mean something like... create very close to the camera an plane object with my original render, then create an hole in it and then render?

If vray sphere fade would support proper background, not only background color, would be that the easiest way....shame, doesn't support.

[MoonDoggie]

Do you mean something like... create very close to the camera an plane object with my original render, then create an hole in it and then render?

If vray sphere fade would support proper background, not only background color, would be that the easiest way....shame, doesn't support.

Yes, make a plane with 3 sub divisions for both directions, and convert to edit poly, delete the center poly. Assign it a matte material and link the plane to the camera (use lookat constraint for the rotation) then animate the verts of the plane to encompass your new object.

[tomtnt]

Thanks guys for an idea. What I have done is...putted a plane in front of my camera, align to the camera and link together. Then in Fusion rendered opacity map from render ID channel and this opacity map loaded to that plane in front of camera. Then I rendered that to format with multiplied alpha channel and then just merged together without any other alpha masking. Works great.

[carlo_cavicchi]

hi,,,,,,i think there is a problem with all this is the fact that vray doesn't create alpha channel of the matte plane when i save in PNG

[hermit.crab]

hi,,,,,,i think there is a problem with all this is the fact that vray doesn't create alpha channel of the matte plane when i save in PNG

You can control the alpha contribution of matte objects through the "Alpha contribution" property in the V-Ray Properties or VRayMtlWrapper (depending on how you're handling mattes). 1 = opaque, 0 = transparent, -1 = shadow catcher.

[Joelaff]

You can also use a (potentially animated) texture as a render mask, which will work better with depth of field and motion blur. The plane trick doesn’t work so well with those because the edges of the mask become soft.


https://docs.chaos.com/m/mobile.action#page/60099357