View Full Version : Problem with IES lights in Cinema 4D 12 + Vray

05 May 2011, 05:37 AM
For some reason, I can't seem to get IES lights to work in Vray. I have carefully checked the following things:

- my scene units are in centimeters
- everything is modelled to scale, i.e. a room is a couple of meters long, not a few inches or kilometers
- I add an omni light, add a Vray Bridge Light tag and change the light to an IES
- I load an .ies file that works using C4Ds standard renderer
- I leave the Power at 0, to use the photometric data from the .ies

In the perspective view I can see the shape of the light, but it doesn't show up in Vray's preview window, and the only way to get any light at all from the IES light is to increase the Photometric intensity under Vray's Options tab from 0.002 to .5, 1 or sometimes even higher. That means that if there is sunlight in the scene as well, it will completely blow out the scene.

I have tried this with tens of different lights, everything from spotlights to flood lights and fluorescent lights, but nothing seems to work. I have tried different combinations of Irradiance Map, Brute Force and Light Cache, but the result is always the same. I have tried manually changing the Power, but nothing seems to work; even entering values as high as hundreds of thousands of lumen make no difference.

Anyone got any ideas what I might be doing wrong?

I am using Cinema 4D R12 Studio 64bit and Vray

05 May 2011, 04:13 PM
I managed to find the problem. I have a huge library of IES files installed, accessible directly through C4D's content browser, which is a huge time saver, since I can just open the content browser and find a light that looks the way I want it to. When using the Advanced Renderer, you can just drag a file from the content browser's preview window to the light, and you're set. That does not seem to work with Vray lights, so you have to manually load the file, then it works.

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05 May 2011, 04:13 PM
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