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Tamis
11-10-2006, 12:18 AM
Hey guys
i have a question about HDRI and SSS Shading.

im curently working on a project for my portfolio so i can show my skills at a company i am aplyng as freebe.
my plan is to run there the rest of the year as im to advanced for my class and i wanna keep learning :D.

any ways im working on this project with another student and our plan is to make just realy short movie of a character walking thrue the school halls.
this is just to keep it all simple and we hope to lakle a more advanced project if this one turns out oke.

so my frend has modled this realy good looking scharacter and its up to me to tecture it and run cloth simulation on it.

so what i did was i made multible maps to use on my skin shader with a basic 3 point lighting setup (key fill back).

it all looks good and all but were planing on using some panorama vieuws and turning them into lightning maps.

so for the heck of it i turned a HDRI maps loose on my model to see what it dose!.

but the model dosnt look nowere near as good as with the 3 point light setup it acturaly looks rather bad. the skin turns rather dark al tho i enabled light tracing in the SSS shader on.

is this a mater of retweaking the whole SSS shader or is there some sense behind this ?

Sincerely yours, the guy that has no sense of grammer :P Tamis van der laan
B-Mac
11-10-2006, 01:40 AM
Ive never had much experience with hdri and sss, but doesnt the hdri light the scene so there is no need for extra lights? (in ur case, 3 point)
Tamis
11-10-2006, 12:16 PM
yes this true and i did only light my scene with a HDRI but somehow the skin gets blown out like it recieves to mutch light, but when i lower the HDri map the skin turns darker but the whole skin just isnt showing its SSS you know.

i have been reading some posts and it seams alot people use one frontal light and a HDRI map as fill light.
Pooba
11-12-2006, 08:22 AM
HA!, I would love to know why hdr seems so widespread, even almost as much as z-brush, yet I can't get a good result with it. Good luck finding a tutorial on making hdr with sss look good.

Looking good is the formidable phrase here. Sure there are plenty of tutorials on hdr, but making it look good? You would think it would be simple. Have the hdr implemented, the fill light, yet it looks like crap compared to the standard light rig. Then you think, it must be something I am doing wrong. You check a lot of different sources, nope, it's fine. Then you think, it must be some combination with sss and hdr, and the render settings that need fine tuning.

After a year of trying different combinations, either I'm just the biggest moron in the world, and I am some how missing the target every single time, or there is a secret to this, like some hdr cult who hides in caverns, trying their best to keep their ancient methods a secret.
Tamis
11-12-2006, 05:42 PM
i bet its all about tweaking the HDRI map Most people probebly makes them themselves
CaptainObvious
11-13-2006, 12:14 PM
The use of HDRIs is widthspread because people are lazy. Why light a scene yourself, when you can just slap an HDRI on it and get "realistic" lighting in no time at all?

At any rate, if you have a 3 point light rig that looks good, why not just stick with that? It probably looks better, and it will tell people a lot more about your skills than an HDR environment would.
giodoc
11-13-2006, 06:19 PM
Hi when using the SSS-shader in maya, you need to adjust the settings, within mental ray:

Scale conversion, SSS-works on the basis of the size of your model, set up weight and colour values in the subsurface tab...

There's quite a comprehensive tutorial on this site, just run a search and it will come up..

Good luck
LucentDreams
11-20-2006, 03:50 AM
most render engines don't support HDRI for effects like SSS. SSS is based of of light, where the HDRI isn't a true light but a GI effect (I assume by HDRI you guys are talking about Image based lighting with HDRI's, more properly called IBL)

To get the effect you will need a a dome area light with the texture applied, or a render engine that has the ability to use IBL to drive caustics and SSS etc.

Some apps have special plugin shaders that can do this too.
OviBogdan
11-26-2006, 07:10 PM
One suggestion I can give you is, turn on photon emission, also, tweak the color gain option on the IBL dome that mental ray creates for you. good luck.
venkie3d
11-27-2006, 01:31 PM
Hey dude , once check ur scene with "Light tracer off", may be it can work.Hope...........
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11-27-2006, 01:31 PM
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