CGTalk - Adding a Gel to a Light

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FranOnTheEdge

08-26-2012, 02:46 PM

Please can someone tell me how to get an image gel onto a light in C4D - the manual says you can add as many as you like, but doesn't say how to do it.
I've tried adding the image to a material and adding that to the light as you would to a selection of faces... or entire object - but it does absolutely nothing.

I've searched throughout the options/controls for the light in question, and again can see nowhere to add an image to drive it...

Please can someone help?

(C4D 10.5 Win7 PC)

Per-Anders

08-26-2012, 03:14 PM

Add the image to the transparency channel of the material before you add it to the light.

FranOnTheEdge

08-26-2012, 04:48 PM

Thanks - it didn't work to start with, until I put the same mat onto another light and realised the problem was that the 1st light had a tick in 'Shadow Caster' - while the 2nd did not.

It now works.

I then tried various combinations because I'd found someone using a gel for tree shadows who said put it in Alpha and turn everything else off. I tried this and it does work, but... well I didn't like it as much as in Trans.

What I did like was a combination of Colour, Diff, Lum, Trans, Reflect, Alpha and Spec Colour which brought out the blue as did trans alone, but also added more punch where Alpha alone had some unappealing yellows to it although it had better deffinition to the pattern than Trans alone did.

I also tried it with the image in Environment as well, but that washed things out again, so it was almost like it was with Trans alone, but a tad brighter.

As I want it to demonstrate the use of the gel - I prefer the top right with most of the options enabled:

http://i251.photobucket.com/albums/gg314/franontheedge/Cinema4D%20Work/4GelsSM.jpg

Thanks very much for your help - you set me on the right road.