Many solutions, but here's an older simple solution: The object emitting illumination should have secondary rays active, and primary rays inactive. This allows rays to be cast for Global illumination, final gathering, etc..., but not be directly visible by the camera. This allows you to use a constant shaded sphere as the emitter.
The object acting as the bulb and visible to the camera should have the opposite settings so it appears in the render, but doesn't block the rays cast by the emitter. You may need to do more subtle tweaking of visibility to account of other situations. For those cases I'll refer you to the 'ray switch' node which can perform the same task at a more granular level. Matt -----Original Message----- From: softimage-boun...@listproc.autodesk.com [mailto:softimage-boun...@listproc.autodesk.com] On Behalf Of Nancy Jacobs Sent: Wednesday, July 03, 2013 3:02 PM To: Softimage Listserve Subject: Requesting advice about light object Hello, I've been away from XSi for about two years due to illness, but am back working on a project. So, this may be very easy for you guys to answer. I'm feeling noobness here, having forgotten so many things! I'm trying to make a small sphere look like a light source, illuminating part of the scene, which is only lit by final gathering and a globe HDR object. I'm pretty sure I've done this successfully before, but it's failing me this time...;-) I can't make the sphere a constant material, because I want it to use many of the attributes of the architectural shader. In other words, I want it to be a reflective ball which is glowing and emitting light. I like the simplified emulated reflections i was getting by using optimizations in the architectural shader (also the rendering time advantage). So, I tried putting a point light inside it, which has somewhat fouled up the nice surface I had going with the architectural shader. And there is no 'incandescence' in this shader to make it appear glowing. I don't want to see the actual point light in the render, but I do want the ball itself to be a bit luminous. I'm also having a lot of trouble with the light attenuation using the exponent. Does anyone have any idea how to measure 'Softimage units' in ones scene? Do they relate to say, the sphere radius I am using? Or is that a whole 'nother thing.... Anyone who can give me some ideas or point me to some info about this glowing sphere light thing, much appreciated... Seems so rudimentary... Thanks, Nancy
