Posted-Date: Mon, 7 Dec 92 13:46:45 PST
Date: Mon, 7 Dec 92 13:46:45 PST
From: ambi@it-next2.bu.edu (Mike Amirault)
Message-Id: <9212072146.AA01040@ it-next2.bu.edu.bu.edu >
To: rman@aero.org
Subject: Shadowing and Lights...


 I have a couple of questions that I have not been able to figure out
on my own:

1) How the heck do you do shadowing within a RIB file?  From reading the RenderMan
   Companion, it would seem as though your supposed to render the image *twice*,
   first creating a depth image and then using that to make a shadowmap. I have
   tried this with very little success.  I tried creating the depth image with
   a Display "test.tiff" "tiff" "rgbz" line and that seems to work but then I
   haven't been able to figure out how to use that image for the shadowing. I
   tried loading it in in a MakeShadowMap(?) call and then using ShadowSpot 

   with that map but no dice...

2) Why don't light sources point in the right direction???  This is maddening.
   I have one light source in my scene, a SpotLight, and I'm trying to have
   it point from the origin (0, 0, 0) down a long hall, say (0, 0, 20). But,
   the light *always* appears to be coming from somewhere else, mostly the
   upper left.  I've tried declaring the light source before WorldBegin,
   after WorldBegin, before transforms, after... etc..

 Any help is appreciated.  


 thanks,
	mike