look through light renders wrong

one of the little “tricks” i do for casting complicated shadows through windows is as follows, but dosn’t work in vray:

create the light you want to cast shadows (directional works best, but spot will do in most cases).
Look through the light and render out a black and white image. In vray I would use a material override and hide what you want behind the windows.

Edit in photoshop, and you have yourself a fairly decent gobo. It won’t match perfectly, I wish it would, but for many situations it works fantastically.

The only problem is Vray isn’t rendering nice with the lights. When you render a light view it is cropped wrong, thus the image you create from it may not be correct.

I just thought I would bring that some attention in case anyone cared.

I’ve had this same problem trying to render out a shadow cast for RPCs. If I remember correct it’s actually a problem rendering out orthographic cameras, not just through lights. For the RPC shadows I just render out a pass through the scanline render, but I’m not sure if this would work in your case.

ummm. thats more or less (in loose concept) the principle behind shadow maps.

yeah, pretty much the idea behind shadow maps, only I don’t want Any shadows. All I want to do is create light on the floor and avoid shadows all together.

Basically I don’t want to have to include the entire scene to just cast a little splash of light on the floor.

the problem is I have blinds and things like that to worry about. Creating it this way gives the illusion that it is accurate and no one ever knows.

I suppose I probably could create a shadow map once then tweak it in photshop and save it? is that what you are saying?

edit: hmmmm, only I don’t know how to save the shadow map.