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View Full Version : Problem with "Show in Reflection"

IBMike
08-17-2009, 10:45 PM
I'm attempting to light a car model that is sitting on a floor that curves up into a backdrop behind it. There is an Area Light being used with "Show in Reflection" turned on to create highlights on the car (studio lighting). The floor material has a Reflection Channel, as the car needs to reflect in the floor.

The problem is that when rendered, the large square Area light also shows up on the background (floor) despite the fact that the Floor is Excluded from the this light and is lit separately.

I've been screwing around with this all day with no luck. This seems to be a Catch 22. You can use an Area light with "Show in Reflection" on, but then anything else in the scene (like the floor) must have its Reflection channel turned off unless you want to see this light reflected in everything. Is this a bug in C4D (it certainly seems like it), or am I missing something?
SilverCity
08-18-2009, 12:26 AM
I'm not sure how to do what you want with Area lights. Why not use a poly with a material with only the Luminance channel on? Add a compositing tag to the poly and exclude the floor.
IBMike
08-18-2009, 12:48 AM
OK, thanks SilverCity. I'll experiment with that.
IBMike
08-21-2009, 08:19 PM
Srek, any chance you could respond to my original question? Thanks
dataflow
08-22-2009, 01:33 AM
try adding a compositing tag to the light.
disabling "Seen by Reflection"
and then include the floor (in the exclusion tab)
IBMike
08-22-2009, 02:58 AM
Hey, thanks for your response Dataflow. It still does the same thing. In the the test scene I posted at the Cafe, if I delete all other light excludes and tags, and just put a compositing tag on Light A like you said, and uncheck "Seen by reflection" and either include or exclude sphere B, the reflection of Light A ("Show in reflection" on) is still present on sphere B.

The bottom line seems to be that if you have a light with "Show in reflection" checked, it will show in every object in the scene (that's exposed to it) that is reflective. There is no tag or setting I can find that can stop it. You can exclude its light, but you can't exclude its reflection.

If there is a way, I'd really like to know what it is.
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08-22-2009, 02:58 AM
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