VRay Override - VRayAO - VRayDirt

[gaara the nightmare]

Hi,

I was trying to find the best way to make an ambient occlusion render in VRay 5.1.
Some interesting new features has been added in that regard but it doesn't seems to be fully ready for my usage, here is my problem:

As I'm doing a lot of watches render I usually have a glass that cover the dial. The new option that preserve refractive/bump/opacity material in the VRayOverride seemed to fit exactly my needs for a fast AO without having to exclude manually all the glass objects of the scene.
I tried to apply a VRayDirt withing a VRayLightMtl and plugged it into the VRayOverride slot and checked the box of the refractive/bump/opacity option. Unfortunately the glass are not excluded and all the object have the VRayLightMtl on them. So my only solution in this situation is to exclude manually the glass object like I was doing previously.

Then I tried the New VRayAO render elements. This one is interesting because it change the background in white so no need to handle this problem manually, unfortunately the glass object are again not excluded, but that's normal because there is no option for preserving the refractive material inside this render element. It also miss an exclude menu to exclude objects inside this render element.

So at the end I'll still have to exclude the refractive objects manually in the VRayOverride and adapt the scene to have a white Background like I was always doing. Is there anything that can be done to handle a VRayLightMtl inside the VRayOverride slot to let me preserve the refractive objects?

By the way I'd like to point that the menu "affected by" inside VRayDirt map is not working in GPU, is It a know issue ? It means that in the case of a watch all the object of the dial will be affected by the glass even if I exclude it from the VRayOverride

I attached some test render to explain the problem.

[hermit.crab]

Thanks for the report. There are some materials that need tweaking when used in conjunction with the Override mtl options; VRayLightMtl seems to be one of them. I'll notify the developers about the matter. For now, use your standard method.
An exclude list would indeed make sense in the VRayAO element, I'll mention this as well.
Regarding the "Affected by" option - it is not yet supported in V-Ray GPU. We already have a logged improvement request (internal bug-tracker id: VGPU-3756).

[matanov]

Looks like the easiest thing we can do is to add a custom background color for the VRayExtraTex RE. This way it will help other workflows as well. What do you think?

[gaara the nightmare]

Hi matanov ,

I think adding a custom background color in the VRayExtraTex RE will be a very nice addition as It will help for some simple situation. However I don't think that it will be the solution for my situation.
I suppose that you can't preserve glass material in the VRayExtraTex RE pass, if the glass object is excluded in the menu of the RE, the object goes black in the render pass.

The best in my opinion would be to tweak the VRayLightMtl to be able to work in the VRayOverride slot.
What do you think ?

[matanov]

You can exclude the glass object in the VRayDirt assigned in the ExtraTex. Wouldn't that work in your case?

[gaara the nightmare]

As you can see in the file attached, the glass is not preserved in the VRayExtraTex RE, even if I exclude them from the VRayDirt.

[piotrus3333]

excluding obj in VRayDirt never worked on gpu.

[matanov]

As you can see in the file attached, the glass is not preserved in the VRayExtraTex RE, even if I exclude them from the VRayDirt.

Have you switched the refractive setting of the glass mtl to affect all channels?

[gaara the nightmare]

Have you switched the refractive setting of the glass mtl to affect all channels?

You're right I had to change the affect channels in refraction, but I also had to do it reflection to make it work in CPU.
I've also tested it in GPU to see if it could work because my main workflow is in GPU, unfortunately the exclusion inside the VRayDirt plugged in the ExtraTex is not working but it does work in the VRayOverride slot as you can see in the jpeg attached.

I've got a question about the custom background you were thinking adding inside the ExtraTex RE, will it react like the environment of 3dsmax? That would be nice to be able to choose between a color or a map.

[matanov]

I'm afraid it will be a pure color only.

[piotrus3333]

Have you switched the refractive setting of the glass mtl to affect all channels?

that has never worked on gpu as well..