CGTalk - compositing shadows

stiki

06-27-2003, 06:57 AM

I've been looking all over the net for a solution to a problem that seems simple.

I'm trying to render the shadows seperatly, because for my animation I want to render the background just once, and then composit in the shadows that the characters are casting.

I've figured out how to use the render layers and render in passes.. but i can't get the shadow pass to work, all i get is a ALL BLACK image.. nothing.. nada.. just black..

what i am doing wrong..

i know a way to render the shadows, but its not using render layers and i would have to set up separate scene file, with background shaders assigned to certain objects... and so on..

PLEASE anyone, if you can point me to a good site, or anything that would help me...

thanks..

Levitateme

06-27-2003, 09:54 AM

hi stiki

ok, i had to figure this out long ago, now im sure there are realy simple methods but mine is very fast though.

there are a few ways
1. you can go to your properties for what you want rendered and click non renderable, then you can get your shadows that way.

2. if you want the entire shadow like if you have a sphere, and you want the whole shadow under the sphere. then use your backround shader, and use render layers, and just have shadows on i belive. i dont have maya open to test this but im sure im telling it to you right . thsi way you get the entire shadow, you can place it behind your object if you want. if you need more help, just msg. again. ciao

alexx

06-27-2003, 10:08 AM

of course your image is black, since maya renders the shadows (when using render passes) in the alpha channel of the shadow image..

in your comp application just take your image and make an "over" with the shadow images.. that does the job

cheers

alexx

anakinskywalker

06-27-2003, 02:14 PM

Alexx is right :applause: Alexx is alway right :applause:

Could you however point out to the background shader assigning thing you mention? I find it curious.

alexx

06-27-2003, 02:18 PM

Originally posted by anakinskywalker
Alexx is right :applause: Alexx is alway right :applause:

not even close to always ;)

anakinskywalker

06-27-2003, 02:28 PM

Alexx is right :applause: Alexx is always right :applause:

there.... ;)

stiki

06-27-2003, 03:14 PM

alexx >> Thank you so much, I could kiss you now.. j/k

anyho.. i sort of had a dream about this last night.. before i went to bed i was thinking why its not working and i think that it might be rendering an alpha chanell..

this kinda thing always happends to me, an easy solution gets in my way..

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