PDA

View Full Version : How to receive shadows from selected objects only.

tozger
01-21-2012, 10:43 AM
I have a bit of a lightning problem;

Scene, edge of a wall is visible and floor is half lit, half of the ground is receving shadow from the wall/ (real footage) cg elements needed to be added, but i need objects in both lit and shadow areas.

I have a cg wall, a ground plane and some debri as elements

I need to make the wall cast shadow on the debri but not my ground object as I already have shadow in the scan.(background shader) and debri to cast shadow on to the ground.

Another way to say this is, the ground plane should receive shadows only from the debri while the debri should receive shadows from all objects.. phew

I think we can call this situation ( Selective shadow Linking)

The problem is, I cannot tell maya to use the wall mesh to cast shadow only on debri but not on the ground ( resulting darker shadows under debries) now i can fix these with seperate layers or later in comp with masks, But I think there should be a way for this..
divanovic
01-22-2012, 11:47 PM
hi,
if I understood correctly, you would need a 3rd light, a negative one with shadows on ... which will be linked to debri and ground and have a negative multiplier of the main light.

you could also post an image of what are you trying to do, maybe I misunderstood.
cheers
Dejan
InfernalDarkness
01-31-2012, 03:56 AM
Using Maya? Look up "light linking" in the help files. It's pretty straightforward from there!
tozger
03-12-2012, 02:53 PM
hi,
if I understood correctly, you would need a 3rd light, a negative one with shadows on ... which will be linked to debri and ground and have a negative multiplier of the main light.

you could also post an image of what are you trying to do, maybe I misunderstood.
cheers
Dejan

Thanks Man, a bit late reply, we faked the shadows in the previous movie but I faced the same issue in a new one, negative light with shadows on worked very well..

Using Maya? Look up "light linking" in the help files. It's pretty straightforward from there!


Thanks for the input man, but the problem here is not to stop lights casting shadows on objects but kinda selective version of receive shadows in Maya, which eventually as Dejan wrote could be faked by creating a negative light....
CGTalk Moderation
03-12-2012, 02:53 PM
This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.