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View Full Version : Matte/shadow annoying problem

Oren Ben-Tov
08-08-2002, 07:36 PM
Hi all
My problem is that say I have got a scene which got a window and a sunlight from the outside with blue shadow casting, that cast shadows on a room with a table floor and a character.

I want to render the character alone for compositing, so I put everything else in matte/shadow with recieve shadow effect alfa option.

the problem is that I also got shadow falling on the table and floor, instead of just the character who will cast shadow on the table and floor.( after that in compositing it makes every shadow darker, or blue)

I tried exluding the wall from the shadow casting but then I wont have shadow on the table and floor and the character.

If I exlude recieve shadow from the floor and table I cant see shadows from the character on the table.

anyone knows of a way how to solve this annoying problem?

Do I need to render it twice?

the character in matte and let it cast shadows on everything.
and then the character with the objects but with out them recieving shadows.( seem like doubling my render time :( )

Thanks for all in advance :)
Oren Ben-Tov
08-08-2002, 07:39 PM
An example of compositing layers -

1.wall outside
2.women with everything else in matte
3.the room

see the blue shadow on everything :annoyed:
Oren Ben-Tov
08-08-2002, 08:03 PM
just the women layer
Black&White
08-08-2002, 09:38 PM
did you work with right clicking objects goto properties. there are controls for object like cast shadow,recevei shadow...
Oren Ben-Tov
08-08-2002, 09:56 PM
thanks for the replay :)
I tried that but when I exlude them in the proprties they wont recieve shadows from the women.
anticz
08-08-2002, 11:36 PM
Duplicate the light and use the include exclude lists on both lights to get what you want. I had to do something similar a while back and that's what I wound up doing. Hope that makes sense.
Joel Hooks
08-09-2002, 05:00 AM
Originally posted by Oren Ben-Tov

Do I need to render it twice?

the character in matte and let it cast shadows on everything.
and then the character with the objects but with out them recieving shadows.( seem like doubling my render time :( )


I would say you need to either use black shadows if thats an option, or render the extra layer.

Here is a list of possible rendering passes from jeremy Birn's digital Lighting & Rendering book


Beauty Pass
Highlight Pass
Reflection Pass
Shadow Passes
Lighting Passes
Effects Passes
Depth Maps


Great book by the way, some really good information in it.

Don't think of it as doubling your rendertime, just think about the additional control you achieve rendering with this method! :D
Oren Ben-Tov
08-09-2002, 09:49 AM
Thanks guys :)

Yesterday I wounded up doing the 2 lights method in the end.

I know I can make a couple of render elements in each frame in max, but how do I sperate them?

if I am rendering shadows and all the image, I get shadow layer and the image frame and again the shadows in that layer,

Is there any way to exlude them from the image element, just to the shadow element/pass?
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