Composite PSD from Elements

[tricky]

This has been covered on and off in various threads, but I am starting to look again at manually building a composite PSD image that *roughly* matches what I see in the frame buffer from the various render elements.

This is what I have so far:-


What I am now trying to do is seamlessly add in 'new' shadows.

For example, say I want to add a person to the render in Photoshop. I stick him in, copy him to create a shadow and skew/rotate/scale the shadow so it roughly matches the lighting setup for where he is standing. Where his shadow overlaps the shadows in the scene, I normally just erase his shadow so that the shadows aren't doubled up. It can be tricky and a bit inaccurate. Also, the colours of the shadows change depending upon lighting conditions.

What I would rather do is have a seperate render element that is just the shadows that I can stack up in Photoshop and paint on to add in all these *extra* shadows.

Does that make sense?

I have tried rendering both the VRayShadows and VRayRawShadows, but I can't quite work out what those elements are and how/if they can be added into the composite stack I already have: the VRayShadows elements seem to also have colours in them.

Is what I am after actually possible?

Do you actually understand me?

Here's a quick example of what I mean:

[tricky]

Maybe I've stumped (doubt it) or confused (more likely) the forum!

[3sgteMKI]

I've run into this before too, but I was using fusion to comp the animation.

I had seperate passes for groups of buildings in an aerial flyover, and when I comped them together I had extra dark areas where the shadows overlapped.

I think It could have been fixed by rendering 2 shadow passes. Say shadows for buildings A and then shadows for building B, then use those to create a pass that is white where the shadows overlap, and black everywhere else, and then that could be used to subtract from the building passes or simply as a matte to brighten up those dark areas and blend them in.

I'm sure somebody's got a better way of doing it though.

[flino2004]

I tryed to do it in photoshop too...but it's very complicate do it there, a node composite software would be much easier.
btw, the column should cast shadow over the person as well.

[tricky]

I tryed to do it in photoshop too...but it's very complicate do it there, a node composite software would be much easier.
btw, the column should cast shadow over the person as well.

Of course, but this was merely a quick example to illustrate by point of combining shadows.

How should VRayShadows and VRayRawShadow elements be used in a composite?

[simmsimaging]

This is a problematic area in vray, IMO. I have not quite figured out how to get a good clean shadow pass from Vray yet. VrayMatteShadow is probably your best bet, but I have not had much luck getting a clean one rendered as of yet.

b

[tricky]

This is rather annoying. I honestly thought I was being dumb with my question and the answer would be reasonably obvious. It seems, so far at any rate, to be not the case.

We have been contemplating Cebas PSD-Manager on and off over the last couple of years but never actually made a purchase. I figured we'd be able to work out our own in-house pipeline for building a composite image that matches the RGB render. Were getting there, but I haven't got a proper match yet.

For anyone who is using Cebas PSD-Manager, does it work well with VRay?
Do you get a seperate shadow element as part of the stack that can have extra shadows manually added to it so you don't have shadows 'doubled up'?
Does it work well with LWF?
Is it a perfect match between the VFB RGB render and the composite?

[vlado]

Normally you would take the VRayMatteShadows element from the scene, invert it, multiply it by the matte shadow of the person, and as a result you will get just that part of the shadow for the person, which does not fall into a scene shadow either. Multiply that by the RGB image and you should get the final result - the person's shadow composited into the scene without overlap (you may need to adjust the shadow strength to match it to the scene shadows).

Best regards,
Vlado

[tricky]

Thanks Vlado. I'll give that a try.