Author Topic: Light visibility with directionality  (Read 10975 times)

2016-02-16, 14:27:07
Reply #15


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I'm talking about having the best result with the minimal work.
And it seems I'm not alone in this .. ;)
No you are not. Need physically correct directional light?
Do nothing.
Need did rectional light to be visible from all angles?
Sacrifice 5 seconds, rightclick rayswitcher and apply to GI, copy material with 0 directionallity to direct override.
I am using light fixtures specified by the lighting designer.  The workflow is currently to plop in a CoronaLight, add the IES file, and set the output in lumens.  Then I add an additional object the size of the light to provide the glow to the camera.  If I could get away with just the CoronaLightMtl, that'd be great, but you can't use IES files with the material (for good reason), the material doesn't show up in the light lister, and the intensity is only in default W/(sr.m^2) units.  You can't use lumens, candelas or lux (lighting designer always specifies lumens to me).  It's usually impossible to get the directionality to match that of an IES file.  And if you want to tweak the size of the disc, you have to recalculate the conversion from lumens to W/(sr.m^2). A direct visibility intensity override for the CoronaLight object, while not physically correct, would save having to make (and keep track of) a separate object just for camera visibility.

The specific case where I would use this all the time is for recessed can lights with a diffuser lens.  To make it look physically real, you would put the CoronaLight inside the fixture, above the lens.  But the IES file already assumes the lens in the output, so to put the IES light above the lens means you're diffusing the light twice.  So you have to exclude the lens from casting shadows.  Plus, now you have to cut a hole in your ceiling to put the fixture in.  I'm as much of a perfectionist as anyone else here, but ain't nobody got time for that! :) I just want a glowing disc stuck to the ceiling.
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