Unique Transparency Issue

[mjm223]

This is a somewhat unique issue that one of my co-workers has run into today.

He want's to make a small, simple render with VfSU, but the alpha transparency layering doesn't seem to work. We've basically used all of the default settings in the V-Ray Options menu, except we're using Light Cache for the secondary engine. Below are the details to this situation:

- We've imported an image of a person in SketchUp, exploded it and then applied the alpha transparency layer to it in the Material Editor (just like I do for all people I import.)

- We're using V-Ray1.05.30 on SketchUp 7.1

- My co-worker has a Mac, but he's able to run Windows XP on it so that he can use V-Ray.

- Unfortunately, I don't have a scene with me, but imagine a simple hallway with brown tile floors, white walls, and a grid ceiling with flourescent tube lights. Now image a student standing in the hallway with a white box around him. (the white box is what's supposed to disappear after having applied the alpha transparency layer to it.)

Does anyone have any idea what the problem could be?

[thomthom]

Re: Unique Transparency Issue

Is there alpha map reversed?

Is the material setting saved? In 1.05.30 there is a bug where unless you open the Option window before you save your file, then all material changes are lost.

[mjm223]

Re: Unique Transparency Issue

Is there alpha map reversed?

Hmm...I don't think the alpha map is reversed. If it were, then the student would be invisible and only the white background would remain. Instead, it just looks like no transparency layer has been added.

Is the material setting saved? In 1.05.30 there is a bug where unless you open the Option window before you save your file, then all material changes are lost.

You might be on to something there. Actually, though, what my co-worker did was he opened a model that I had made in the past, copied the people I had in it, and pasted them in his model. Usually when I do that, the materials lose all of their properties and they have to be re-assigned, which I thought was the case here. But it doesn't seem to be the case with the alpha transparency layer.

Funny thing, though, all of the other material layers (reflection, emissive, refraction, bump, etc) work fine, but not the alpha transparency.

[thomthom]

Re: Unique Transparency Issue

You got some screenshots of the material in the material editor and the transparency map settings?

[mjm223]

Re: Unique Transparency Issue

I managed to nab a screenshot. Below is how the rendering looked after applying the alpha transparency map.


And here is a screen shot showing that the alpha transparency map was applied to the girl in the red shirt. What's crazy is that the preview shows that the alpha transparency layer is working, but when we render the white box around the girl remains. This is the same case for all the people in this scene.

[thomthom]

Re: Unique Transparency Issue

???
well - that has me stomped...

What package are the people from?

[mjm223]

Re: Unique Transparency Issue

The package of people came from a friend of a friend a while back. I've been using them for the past couple of years and have never run into a problem like this.

I've got a feeling there's more to this model than meets the eye. My co-worker had just told me that one of his students made the model for him, and he's just trying to get it to render properly in V-Ray.

I have no idea what kind of computer his student used to make the model, but I know my co-worker is editing the model on his Mac, which has Windows XP installed on it. Given that V-Ray 1.05.30 wasn't compatible to Macs and that there are some minor difference between Windows XP on a Mac and Windows XP on a PC, maybe these variables play a role in all of this?

I haven't been able to get my hands on the actual model yet to see if it'll render properly on a PC. But when I do, I'll keep you posted.

[a3rosmith]

Re: Unique Transparency Issue

try to invert the alpha channel in the options of your alpha

[40th]

Re: Unique Transparency Issue

Does this Co-worker of yours using vfs 1.00 ?

[mjm223]

Re: Unique Transparency Issue

try to invert the alpha channel in the options of your alpha

I've already tried this. Nothing is affected by the alpha layer, whether or not it's inverted. V-Ray acts as if the alpha layer was never applied.

Does this Co-worker of yours using vfs 1.00 ?

He's using VfSU 1.05.30. My guess is that the problem lies in his computer. He's using a Mac, which this version isn't compatible with. But he has Windows XP on his Mac, which allows him to use V-Ray. I doubt Windows XP on a Mac works exactly like it would on a PC, and I believe this difference is what's causing the problem. I don't know for sure though, and so far, that's the only problem I've found on his computer.