erkutacar Posted February 29, 2012 Share Posted February 29, 2012 is it possible to get coloured caustics like a crystal without using an environment map?? coz i want to get exactly the same effect as in the photo below.. i already modeled the light and gave IOR of 2.541 (diamond) and now i want learn a way to get the effect i want [ATTACH=CONFIG]47233[/ATTACH] Link to comment Share on other sites More sharing options...
Brodie Geers Posted February 29, 2012 Share Posted February 29, 2012 What rendering engine are you using? In Maxwell, that would just entail turning on 'dispersion' in the material. You might google that word along with your engine's name and see if anything pops up. -Brodie Link to comment Share on other sites More sharing options...
erkutacar Posted February 29, 2012 Author Share Posted February 29, 2012 hmm ok ill try, its mental ray Link to comment Share on other sites More sharing options...
erkutacar Posted March 1, 2012 Author Share Posted March 1, 2012 dude im f'ing going crazy here maybe u could help here is the render of the light fixture i showed above.. [ATTACH=CONFIG]47236[/ATTACH] now all that except the wall is grouped.. i import it into a building model.. i place it on a wall with the same texture.. i use the same render settings.. but i dont get the same result. this proper renders photon calculation took about a minute but the one below takes a second! so it skips photon calculation. why could that be? oh and no matter how much i increase the photons it still takes 1 second! ive been trying to figure it out for ours when i was at the office, scene didnt produce any caustics at all.. i worked a couple hours so i gave up and just deleted the light, put a new light with the same settings and it worked so im assuming its a max bug like that? and as u can see its more reddish eventhough they have the same kelvin values here is the one with the problem: [ATTACH=CONFIG]47237[/ATTACH] Link to comment Share on other sites More sharing options...
Brodie Geers Posted March 1, 2012 Share Posted March 1, 2012 I wish I could be of more help but I know very little about Mental Ray. I could ask a few questions but it sounds like you've eliminated all of these possibilities. Is there a particular setting in MR that allows caustics to be generated? Are the crystal materials identical in each case? If you're getting the desired result before you pull the light into your building model, have you tried reversing that and importing your building model into the file with your light? It sounds like you've got the first two covered. The last would simple make 100% there there isn't an issue with different settings and that the only difference is the surrounding building model. Sorry, I hope a MR expert can chime in here. -Brodie Link to comment Share on other sites More sharing options...
Umesh Raut Posted March 1, 2012 Share Posted March 1, 2012 In Vray there's the new material property called dispersion which handles such things based on IOR and abbe # so you may have to look for a similar setting in mental ray (should be in it). Link to comment Share on other sites More sharing options...
erkutacar Posted March 1, 2012 Author Share Posted March 1, 2012 umesh, mental ray doesnt have that yet so i need to get a good photon shader for it and now im searching for one. brodie, no i havent tried to merge the building and the light fixture into a new file coz i have so many objects in the building i couldnt bother and yes there is a perticular setting for caustics in mental ray.. and its fairly simple.. i guess i will have to merge them if i cant get it to work soon.. what do u think of the first render? does it look ok comparing to the original photo? Link to comment Share on other sites More sharing options...
Brodie Geers Posted March 1, 2012 Share Posted March 1, 2012 I'd say it's so-so. The caustics look fine but without the rainbow dispersion patterns there's no hint of the fact that we're looking at crystal rather than plastic. And the crystals themselves are very dark whereas in the original picture they're nice and clear like a diamond commercial. I think that what you're doing is extremely tricky though. Some people specialize in jewelry renderings which take a lot of special care to light properly to best show it off. You've got the same issues but you're also dealing with a light fixture. That would be one thing in an unbiased engine but with MR you may need to dig deep into your bag of tricks to pull it off. You may get away without the dispersion if need be, but you should at least find a way to light the crystals so they're not so dark. -Brodie Link to comment Share on other sites More sharing options...
erkutacar Posted March 1, 2012 Author Share Posted March 1, 2012 how about now? i added 50% white translucency.. and also made the light cooler.. but u cant really match that photo coz they probably have a white reflector in front of the light.. [ATTACH=CONFIG]47243[/ATTACH] Link to comment Share on other sites More sharing options...
Brodie Geers Posted March 1, 2012 Share Posted March 1, 2012 That's much much better. You could mimic the white reflector by using a large low powered light. Might be worth trying. -Brodie Link to comment Share on other sites More sharing options...
erkutacar Posted March 1, 2012 Author Share Posted March 1, 2012 yes but my goal is not to render light fixture.. this will be mounted the throught out the corridors of a residencial building Link to comment Share on other sites More sharing options...
erkutacar Posted March 1, 2012 Author Share Posted March 1, 2012 ive tried merging them into new scene but didnt work.. it still does photon calculation in 1 sec Link to comment Share on other sites More sharing options...
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