Object still partially visible even with material wrapper

[evanerichards]

I have an object that I applied a vray material wrapper to. I turned on matte surface, and turned alpha contribution down to -1 but I can still see the object. It is semi-transparent dark gray. I can't for the life of me figure out why I can still see it.

I can't post a scene file right now, but was wondering if someone had any ideas about why this might be happening.

Thanks!

[CerpinTaxt]

Maybe the Reflection and Refraction Amount under the Matte Properties are still at 1.0 and your object is still catching reflections / refractions?

[evanerichards]

So I found the problem and the solution completely by accident. It wasn't the reflection and refraction amount that was causing the problems. It's motion blur. When I turn on camera motion blur, or the vray physical camera motion blur the object stops being invisible and turns transparent dark gray (at least it looks transparent gray over an image plane background)

Although I'm not certain exactly what to do now if I want to turn on motion blur.

Very strange.

[ivaylo.ivanov]

Can you share a scene with this effect?

[evanerichards]

It's a scene from a film, so I can't really post it but if I have time I'll try to recreate it and send that to you, because I'd really like to get that bug figured out.

[evanerichards]

Ok. Here's a scene. You have to add an image into the camera's image plane to see it, but once you do this scene should show you the problem.

https://www.dropbox.com/s/m5jcu1m89z...erTest.ma?dl=0


I'm on V-Ray for Maya version 2.30.02 core version 2.00.01 at the moment. It's possible this is an issue that was fixed in a new version of vray.
Let me know if you can duplicate this problem. I'd be interested to know.

Thanks!

[georgi.zhekov]

Hello,

We can't seem to reproduce it in here - we tested in on 2.3 , 2.4 and 3.0 and it looks good.

Can you reproduce it with any image plane?

[evanerichards]

So strange!
I can reproduce it with any image plane that isn't pure white (because then you just can't see it, even though it's probably still there)

Try this scene.
https://www.dropbox.com/s/qdw80lfipz...rTest2.ma?dl=0

In this scene the object shows up a darker gray when you turn on motion blur. I just used a plain white background and rendered it and this is what I got:

[Dav3Design]

Sorry to hijack but I am getting the same issue when using VRay Object Properties with 3.1.

Things are still partially showing up in the alpha and render elements.

Any clues?

[evanerichards]

I have a clue! So, we were trying a whole bunch of things, and we've narrowed it down to render settings. One of the of the other guys tried rendering the scene starting out with default vray render settings and it went fine. We still can figure out which setting is the offending culprit though. I'll post here if I figure anything else out.

[ivaylo.ivanov]

No, we still can't reproduce this issue on our side.

[evanerichards]

Strange. Maybe I can send my vray settings? You can import those and see if you can reproduce it then?

[Dav3Design]

Reducing the reflection and refraction properties in the VOP does seem to fix it but I never had to do that in 2.4

Is this something that changed in 3.1?

[evanerichards]

Ok. I figured it out.
If you turn your geometry smaples (vray settings, vray...camera...motion blur... from 2 to 4 the object should appear (did for us anyway). The higher you turn up the geometry samples, the darker the shadow gets.
I'd be interested to see if any of the vray developers can confirm this for version 2.30.02.
It seems to be fixed in Vray 3.0.