PDA

View Full Version : mental ray: excluding objects from lights

meanlebh
06-01-2006, 04:29 PM
I have been having a problem when lighting (mainly indoor scenes) using mental ray. The issue is that when excluding objects from certain lights, they still cast shadows from those lights when using shadowmaps (when raytracing them they seem to work fine). This mainly causes issues when I am making my bounce lights (for a ceiling, floor, wall, etc...). I will have the bounce light for the ceiling shining up through the floor, and have the floor excluded from the light. The light does not illuminate the floor at all which is correct, but it still casts a shadow and blocks the light from the ceiling and the rest of the room. Of course there are many other problems that are created by this, but this is just one obvious example...

I am using xsi 5.1 and mental ray as I stated above, if anyone here could maybe clue me in to why this is happening or what I am doing wrong if perhaps I am just missing something.

Any help would be greatly appreciated! thanks!

Also please let me know if any of this isn't clear and I need to reword it in anyway.

-Brian
AndrewRaZ
06-09-2006, 08:37 AM
not sure about xsi, but light linking in maya usually fixes stuff like that. if the light linking isn't working, however, turn the shadows off on your light, and try using a separate light for the shadows with a negative value.
meanlebh
06-09-2006, 02:01 PM
Thanks Andrew for the reply. Your workaround will help to solve the issue some, and I have been able to avoid most problems with this by just making sure that my shadow lights are placed carefully...although it is kind of a pain to have to use workarounds when the problem should be able to be solved easily enough...

Thanks again for the reply, I was hoping that perhaps I was just doing something stupid, but it looks as though it is some sort of bug in xsi....is anyone else out there having similar issues with xsi at all?

Thanks,

-Brian
meanlebh
06-09-2006, 02:02 PM
Thanks Andrew for the reply. Your workaround will help to solve the issue some, and I have been able to avoid most problems with this by just making sure that my shadow lights are placed carefully...although it is kind of a pain to have to use workarounds when the problem should be able to be solved easily enough...

Thanks again for the reply, I was hoping that perhaps I was just doing something stupid, but it looks as though it is some sort of bug in xsi....is anyone else out there having similar issues with xsi at all?

Thanks,

-Brian
meanlebh
06-09-2006, 02:24 PM
whoa...sorry for those multiple posts.....
CGTalk Moderation
06-09-2006, 02:24 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.