strange self-illumination behaviour

[nelpiper]

Hi guys. I'm using max 2009 x64 and win xp x64. I've been using vray for over 1 year and now I want to get some skills on mental ray too. There is something going on with mental ray rendering though. The same image was rendered used the new mr photographic exposure and logarithmic exposure. The one rendered with the photographic exposure is not showing the self-illuminated material applied to the recessed lights while the one rendered with the logarithmic exposure does. Any ideas why not? Could that be a bug? I've got sp1 and latest hotfix installed.

Thank you.

[nelpiper]

Hi guys. I figured out what happens. When using the mr photographic exposure and photometric lights, the physical scale is calibrated to real world intensity lights (photometric). Since I'm using a self-illuminated material which is not a floating point light, it's far too week to show up in the rendering. The solution was to add an output map to the self-illumination slot and raise the output amount up to (in my case) 1000. That solved the problem. Thanks anyway and I hope this help anyone who's got the same issue.

Thanks.

[SandmanNinja]

Hi Nelson,

 

Yeah, I get the same behaviour when I have desk lamps and bedside lamps that I want to cast a 'light pool' on the wall or desktop. I end up setting the output to about 3000 or so candellas and that gets me the effect that I want.

 

Using a real 60-watt light globe in a real-world lighting situation won't contribute enough light compared to the sun and what-not.

 

Glad you got it sorted.