Shadow/matte-material issue in Maya

[tailorstore]

Hey!

I work for a web-based fashion-company as a 3D-graphics artist using Maya and we recently discovered Octane. It's awesome. Upon contacting support regarding the possibility of rendering a separate "shadow pass" or a layer containing only shadows in aplha, alternatively black shadows on white, I was told this was not possible in the demo but implemented in the full version. However, when purchasing the standalone/plugin-pack it did not work.

I contacted them/you again, confirming this was a bug and that the "matte" checkbox for diffuse materials indeed did.. nothing. I was then very pleased at the quick response I got and was told this would be fixed in a soon-to-be-released update.

There, now if anyone else was wondering about shadows in Maya (because let's face it, documentation is a bit scarce).. you might have gotten some insight in the matter

[JimStar]

Don't worry please, the next release with matte bug fixed (and some new features) will be in a few days...

[tailorstore]

Don't worry please, the next release with matte bug fixed (and some new features) will be in a few days...

Great! Looking forward to it, keep up the awesome work

[tailorstore]

So the new version of the Octane for Maya plug-in is now available and I've been trying it out for an hour or so, but there's still still this one thing I just can't seem to get right.. The Matte-option is now working, enabling alpha-masking as it's supposed to, but the desired effect of casting shadows on non-visible objects still seem to.. not?

I'm attatching this image to (hopefully) show what I'm referring to:


It still seems as this checkbox, in the image below, does.. nothing? Or am I just missing something very obvious?


Thanks!
Robin

[TBFX]

Hi Robin,

I was playing with this today and you need to give the diffuse material some transmission for it to work. Just a tiny value will do like 0.001, oh and set the matte material colour to black.

The attribute you have circled in the render globals is to turn on shadowing of objects based on an opacity map and has always been there, but if you leave it unchecked and set the opacity of the shaders on your shadow casting objects to 0 you can get a clean shadow pass.

T.

[tailorstore]

Hi Robin,

I was playing with this today and you need to give the diffuse material some transmission for it to work. Just a tiny value will do like 0.001, oh and set the matte material colour to black.

The attribute you have circled in the render globals is to turn on shadowing of objects based on an opacity map and has always been there, but if you leave it unchecked and set the opacity of the shaders on your shadow casting objects to 0 you can get a clean shadow pass.

T.

You are completely right! Everything now works just as expected. Thank you very much, sir

[tailorstore]

On another shadow-related post.. We're trying to achieve having an object (A) casting shadows on a matte/invisible object (B) without having object B casting shadows onto itself. The "Cast Shadows" and "Recieve Shadows" options aren't supported, is there another way to achieve the same result? See below.

What I want is for only the hands (and stick, don't worry, it's just a cylinder ) to cast shadows onto the fabric (in alpha) but the fabric can't cast shadows onto itself since when combining the two images (rendering fabric and hands separately) this will result in double the shadows for the fabric layer.


Thanks!
Robin

[TBFX]

On another shadow-related post.. We're trying to achieve having an object (A) casting shadows on a matte/invisible object (B) without having object B casting shadows onto itself. The "Cast Shadows" and "Recieve Shadows" options aren't supported, is there another way to achieve the same result? See below.What I want is for only the hands (and stick, don't worry, it's just a cylinder ) to cast shadows onto the fabric (in alpha) but the fabric can't cast shadows onto itself since when combining the two images (rendering fabric and hands separately) this will result in double the shadows for the fabric layer.

It doesn't appear to be possible, not at this time anyway.

This is something that makes the shadow catcher only useful for very simple scene integration and we really do need to be able to set shadow catching geometry to not cast shadows when appropriate.
For a full CG integration workflow we also need the ability to have objects invisible to primary rays but still contribute to the scene in every other way. I don't know how difficult these things are in a path tracer but it is what is needed.

Robin,

In your scene do you absolutely need to render the parts seperately? Above I'm really talking about integrating CG with live action plates but if the scene is completely CG could you render it all in one pass?
I know there are several reasons you may want seperate passes, including rendering in different renderers, but if it's not possible then maybe a single pass and an ID pass would work. My personal opinion when rendering full CG with an unbiased renderer is it's always best to do it in a single pass if at all possible.

T.

[tailorstore]

In your scene do you absolutely need to render the parts seperately? Above I'm really talking about integrating CG with live action plates but if the scene is completely CG could you render it all in one pass?
I know there are several reasons you may want seperate passes, including rendering in different renderers, but if it's not possible then maybe a single pass and an ID pass would work. My personal opinion when rendering full CG with an unbiased renderer is it's always best to do it in a single pass if at all possible.

T.

Unfortunately I do, since I'm rendering items of clothing, in this case a shirt, and I need to be able to switch out the collars and cuffs in different colors/fabric or designs (a set amount of different cuts).. The alternative is to render these items without shadows and do only shadows alone in Mentalray, since the color/fabric doesn't affect shadows, only the general shape of the object. Well, let's hope this feature might get implemented in the future

[tailorstore]

Hey!

We're still dealing with some shadow-issues here, so I'm wondering if there's been any development in regards to this? Mainly, what remains to be our main problem is, as mentioned above, there seem to exist no "cast/recieve shadow" option.

What we need is to render objects separately, casting shadows on objects, which in turn do NOT cast shadows on themselves. That is "cast shadow" off, but "recieve shadows" on. See picture below. Any ideas?