Rendering out the shadows with vray in a seperate file...

[net_ralf]

How do you render out the shadows with vray 1.09n in a seperate file? It seems the Matte/Shadow doesnt work that come with max. The only thing that seems to be close enough to the thing i need is the VrayMtlWrapper? If it is the one i need then how does it work, if not any other suggestions.

Thx a lot

Ralf

[Seraph135]

you were almost there.

Select all your objects and assign a vraymtlwrapper to them. Check matte surface and shadows. Change the color to white. Make sure to turn on "smooth surface shadows" in your vray lights. This will render like a normal image and not like maxs render elements where the shadow appears on the alpha. Adjust accordingly in your composite.

Well, theres one method. I'm sure there are others.

Tim J

[net_ralf]

Just to be sure if this is what u mean...

I think I figured it out with your help, however the quality seems very strange to me ( maybe my own fault. As well i discoverd that it only works if i give it a base material, so i just chucked a normal unedited vraymatl in there. Is that correct or is this the reason for my funky render? If i understand it correctly now i have to render the scene twice. Once with all the materials on it and without a floor and then apply the wrapper and render it again with a plane which gives me the shadow?

You also told me to change the color to white which i did. So the shadow comes out white with a gradient towards black. My knowledge about composeting is not the best so i tried it in photoshop and after effects. However it only looks good when i inverted the shadowd so it starts with black inside and goes to white. It looks nice if u have a white canvas in a lower layer. Once u change the color to something else like blue u see the white in the shadow. Its not really the alpha i wanted I do assume that this is the lack of knowledge of compositing and vray. Hope you or someone else can point me in the direction. Thank you very much for your help so far

Ralf

Ps: Maybe you or someone else could create a tiny scene with one light a cube and a plane with the setup of rendering the shadow and send it to me as a rar or zip file to

net_ralf@hotmail.com

Cheers

[Seraph135]

Alright. Your last post was a little more specific.

There are lots of factors you need to be aware of to composite this correctly. If your using GI then you have to do things differently than if you aren't. You might be able to get away with just throwing a wrapper on top of your current floor materials and use the settings I recommended. It really depends on the scene though.

I recommend doing it in 3 passes. However, you can do it in two or many depending on how much control you want in the comp.

1) Your scene without the object.
2) Just the object your adding.
3) a shadow pass for just the object your adding.

There is little difference between the method I described in my first post and if the same thing was on an alpha channel. In fact, the way I mentioned will create smaller files since you don't need the alpha channel. I typically use a shadow pass like this as a mask on a layer that is a solid color (the color of my shadow).

Try reading through the compositing tutorial on my website.

http://www.seraph3d.com/composite_main.htm

Tim J

[Alex Doss]

..... " I typically use a shadow pass like this as a mask on a layer that is a solid color (the color of my shadow). "

Try to use the same difuse composed over Multiply, as opposed to using a solid color. Brings out some color details on the penumbra, very handy !

Lots of variations on this method as well. I just like to avoid using solid colors for this king of FX.

=) cheers