Maya 2020 fundamentals - modelling the real world
Get halfway through a model and find it's an unworkable mess? Can't add edge loops where you need them? Can't subdivide a mesh properly? If any of this sounds familiar check this course out.
# 1 18-05-2012 , 09:57 AM
Registered User
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

Attached Thumbnails
# 2 18-05-2012 , 04:41 PM
honestdom's Avatar
The Nurb Herd
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
Registered User
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
The Nurb Herd
Join Date: Oct 2007
Location: London
Posts: 2,381
Yeah I bet! Best of luck with the assignment.

Posting Rules Forum Rules
You may not post new threads | You may not post replies | You may not post attachments | You may not edit your posts | BB code is On | Smilies are On | [IMG] code is On | HTML code is Off

Similar Threads