Introduction to Maya - Modeling Fundamentals Vol 2
This course will look in the fundamentals of modeling in Maya with an emphasis on creating good topology. It's aimed at people that have some modeling experience in Maya but are having trouble with complex objects.
# 1 18-05-2012 , 09:57 AM
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Join Date: Oct 2010
Posts: 234

caustics super bright

hi,

I'm trying to render out a scene with a few bottles etc. in it - it's looking ok with global illumination and final gather, but the minute I switch on caustics it goes crazy. I read that you can't use directional lights (emitting photons) with caustics, so I switched off the photons on my main directional light and it fixed the problem but the resulting render had little 'zing'.
I switched photons on in the small point lights I have around the fg table and dialled down the global photons but I get these really burnt out brights. all the point lights have quadratic decay and are low intensity (tho I've been told that light intensity and photon volume/intensity are independent?)
It seems to be one material thats particularly prone to burn - you can see the very bright glass in the center, and also in the bg there's glasses with the same material glowing like mad. It's a miaX material, just a few standard glass presets blended together... all the other glasses have similar miaX blends applied. that said, the table is a standard anistropic, which still glows like mad even when I apply the initial lambert to it.

is there certain materials that're no-no's with caustics, or is there a particular limit to the total number of photons you should have in a scene? for example, if i have a point light or small spot that I'm using close to an object to create a few rim hi-lights ect. do I need to dial the number of photons down? there's quite a few lights around the fg so my thinking is that all the total number of photons is too great around that area. but of course, I don't know what I'm on about...user added image

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# 2 18-05-2012 , 04:41 PM
honestdom's Avatar
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Join Date: Oct 2007
Location: London
Posts: 2,381
does your scene take more than a minute to render? your lighting setup seems really over the top. its not clear what the mood is, or any kind of light direction.

i'm not sure i can help you, i've only ever used photons once (when i was studying). i certainly use FG and GI together.

# 3 18-05-2012 , 08:58 PM
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Join Date: Oct 2010
Posts: 234
it probably is OTT - though in my defence, each of the lights has been placed to create a shadow or to light a particular area or section of geometry. It's for a uni assignment and I'm more interested in tackling the various types of lights, materials and settings. I'm not knowledgeable enough about them to be able to create a 'mood', nor to be honest, interested enough in it to feel it warrants a great deal of artistic endeavour; i'll probably never attempt another scene like this. But I agree it suffers from more than it's share of newbies insecurities - more is more; or so we think. I guess the closest 'style' would be noir-ish, where the graphic shape of shadow takes precedence over realism.
It's too late to start worrying about that now anyway, I think I've got a handle on things with dielectric materials! =S
oh - yeah it takes a few minutes to render, but so did the tutors during the demos - it's cut down quite a bit once the gather map is frozen. some of the other guys are taking hours!! user added image


Last edited by se7enhedd; 18-05-2012 at 09:01 PM.
# 4 18-05-2012 , 10:18 PM
honestdom's Avatar
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Join Date: Oct 2007
Location: London
Posts: 2,381
Yeah I bet! Best of luck with the assignment.

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