shadow passes: is it just me or is this a pain in the a&# ?

[simmsimaging]

I'm not sure if it is just me, but I have no end of problems getting a decent shadow pass out of Vray. I haven't used it in a while but I remember it being pretty easy in mental ray. Am I missing something? I have read the threads I could find, just hoping someone has an answer I couldn't find.

VrayMatteShadow just renders like crap most of the time - artifacts and grainy and almost always useless to me or in need of heavy post manipulation. VrayShadow does not give me the actual shadow alone - it needs an alpha for the shadow only etc.

I just need a simple shadow pass that I just shows shadows that I can multiply into a shot. Any tips?


*EDIT* - I should say I am aware that I can render the object as matte, use the VrayShadow pass and combine that with the alpha, but then I have to render every lighting pass twice so I can have the shadow catching object rendered as well, or a proper alpha for the object casting shadows etc. It just seems very cumbersome.


Thanks in advance
b

[vox3D]

Have you tried the VrayRawShadow pass? If you take that, invert it in Photoshop, then multiply it in it should do what you're asking for.

[simmsimaging]

nope - didn't see that one so I'll give it a try. Thanks
b

[simmsimaging]

So I gave it a try - it's pretty much the same as the VrayMatteShadow. It too is noisy. Is there some other way/trick people have of getting a good shadow pass without a lot of aggravation?

Thanks
b

[werticus]

if its too noisy is it a render quality problem? Ie more light samples etc?

[simmsimaging]

It does not seem to be directly related. The samples are good enough in the beauty pass. I think Vlado explained the reason for this before and there's not really much you can do about it, that's why I'm trying to figure out a good workaround.

b

[vlado]

It does not seem to be directly related. The samples are good enough in the beauty pass. I think Vlado explained the reason for this before and there's not really much you can do about it, that's why I'm trying to figure out a good workaround.

b

The samples in shadow element are the exact same samples as used in the RGB element, however V-Ray will only put enough of them to get a good RGB image. You can try increasing the shadow and light settings to improve them.

Best regards,
Vlado

[smashley]

That's too bad. I wish it were a cleaner element too.

[simmsimaging]

The samples in shadow element are the exact same samples as used in the RGB element, however V-Ray will only put enough of them to get a good RGB image. You can try increasing the shadow and light settings to improve them.

Best regards,
Vlado

That could get expensive in terms of render time though.

b

[vlado]

That could get expensive in terms of render time though.

b

Yes, of course; that's why V-Ray only takes as many samples as required for the RGB image

Best regards,
Vlado

[simmsimaging]

So no good (cheapish) workarounds?

b

[vlado]

None that I can think of right away other; it might be a good idea for us to add the "consider for AA" option to all render elements, and not just the ExtraTex one.

Best regards,
Vlado

[horoXhoro]

None that I can think of right away other; it might be a good idea for us to add the "consider for AA" option to all render elements, and not just the ExtraTex one.

Best regards,
Vlado

great idea when it coming along. post work is very important. thanks vlado