do you use photometric lights with GI?

Brian Cassil · May 18th, 2006

I've gone back and forth on this maybe 6 or 7 times, and I'm curious to know what others do. I like the photometric lights because I get better reflections with them but they also seem to wash out the scene more. It may be that I am doing something wrong though. I like the standard lights because for me they are more flexible, without having the dynamic range of photometrics my reflections never look quite right. Again, I could be doing something wrong.

Personally I use Final Render, but I would like to know from users of any renderer what kind of lights they use.

Rick Eloy · May 18th, 2006

Well, I normally use photometric lights and never had a problem with them. They work well with VRay (although a bit slow) and very well with radiosity. Not only reflections look good, also the whole lighting gets smoother and way more natural.
I guess the trick is you have to treat them as you would treat real lights. I normally work in Lux instead of Candelas (all technical specifications I get are in Lux, so...) and they work sweet.

rmoore97 · May 19th, 2006

hey brian, we just started using photometric lights with finalrender where i work and really the only problems we have encountered is if you have the standard raytrace shadows set instead of fR raytrace shadows - then we have experienced crashes. other then that i love the photometric lights, and you can still cheat with them a little if you need to, by adjusting the multiplier, changing candelas or even using the exposure control.

randy

Sawyer · May 19th, 2006

I have been using Chris Nichols' tip that he showed in the interiors DVD. I Use a photometric file creator. Their are way too many photometric files out their and most of the time I don't get specs on lights so I can fudge them this way. I would spend all day testing files till I found the ones I liked.

That all in vray.

Rick Eloy · May 19th, 2006

[quote=Sawyer]I have been using Chris Nichols' tip that he showed in the interiors DVD. I Use a photometric file creator. [quote]
That sounds interesting. How does it work? I mean, I've seen people writing their own IES file, but I simply don't have what it takes to do it.

Sawyer · May 19th, 2006

I have a program its called ies_gen3 its a free thing I found online. I am sure there are better ones. Chris used one in his dvd that looked better but I have forgotten it's name. Anyway you can just draw a profile of light, save it and use that as your web distribution file.

Here are some screen captures of the program, wire of the light and result.

Rick Eloy · May 19th, 2006

Sweet! I'm gonna check it out. Thanks!

May 18th, 2006	#1 (permalink)
Brian Cassil Moderator Join Date: Apr 2002 Location: Salt Lake City, Ut. Age: 36 Posts: 2,014 Name: Brian Cassil	do you use photometric lights with GI? I've gone back and forth on this maybe 6 or 7 times, and I'm curious to know what others do. I like the photometric lights because I get better reflections with them but they also seem to wash out the scene more. It may be that I am doing something wrong though. I like the standard lights because for me they are more flexible, without having the dynamic range of photometrics my reflections never look quite right. Again, I could be doing something wrong. Personally I use Final Render, but I would like to know from users of any renderer what kind of lights they use.

May 18th, 2006	#2 (permalink)
Rick Eloy Moderator Join Date: Apr 2002 Location: São Paulo, Brasil Age: 31 Posts: 2,385 Name: Ricardo Eloy	Re: do you use photometric lights with GI? Well, I normally use photometric lights and never had a problem with them. They work well with VRay (although a bit slow) and very well with radiosity. Not only reflections look good, also the whole lighting gets smoother and way more natural. I guess the trick is you have to treat them as you would treat real lights. I normally work in Lux instead of Candelas (all technical specifications I get are in Lux, so...) and they work sweet. __________________ Rick Eloy reb digital - Really, I'm doing it for the kids...

May 19th, 2006	#3 (permalink)
rmoore97 Junior Member Join Date: Mar 2004 Location: Columbus, Ohio Posts: 27 Name: Randy Moore	Re: do you use photometric lights with GI? hey brian, we just started using photometric lights with finalrender where i work and really the only problems we have encountered is if you have the standard raytrace shadows set instead of fR raytrace shadows - then we have experienced crashes. other then that i love the photometric lights, and you can still cheat with them a little if you need to, by adjusting the multiplier, changing candelas or even using the exposure control. randy

May 19th, 2006	#4 (permalink)
Sawyer Veteran Member Join Date: Jun 2002 Location: CA Age: 34 Posts: 1,563 Name: Sawyer Fischer	Re: do you use photometric lights with GI? I have been using Chris Nichols' tip that he showed in the interiors DVD. I Use a photometric file creator. Their are way too many photometric files out their and most of the time I don't get specs on lights so I can fudge them this way. I would spend all day testing files till I found the ones I liked. That all in vray. __________________ And you may ask yourself What is that beautiful house?

May 19th, 2006	#5 (permalink)
Rick Eloy Moderator Join Date: Apr 2002 Location: São Paulo, Brasil Age: 31 Posts: 2,385 Name: Ricardo Eloy	Re: do you use photometric lights with GI? [quote=Sawyer]I have been using Chris Nichols' tip that he showed in the interiors DVD. I Use a photometric file creator. [quote] That sounds interesting. How does it work? I mean, I've seen people writing their own IES file, but I simply don't have what it takes to do it. __________________ Rick Eloy reb digital - Really, I'm doing it for the kids...

May 19th, 2006	#7 (permalink)
Rick Eloy Moderator Join Date: Apr 2002 Location: São Paulo, Brasil Age: 31 Posts: 2,385 Name: Ricardo Eloy	Re: do you use photometric lights with GI? Sweet! I'm gonna check it out. Thanks! __________________ Rick Eloy reb digital - Really, I'm doing it for the kids...

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