diamond caustic

# 1 14-08-2009 , 05:07 AM

Registered User
Join Date: Mar 2005

Posts: 6

Hi All...

Not sure if this is a Mental Ray or not...

Couple of questions on a diamond tutorial I was following.

> Why am I am getting so much grays, and not enough strong darks and lights?

> Why isn't my gradients nice and smooth? If you look closely, there seems to be something like dithering going on.

I went over the tutorial very closely and even the files. Not sure what I'm missing or what went wrong.

i pointed out the dithered areas in red.

links:
https://www.rossow-web.com/diamonds.jpg
https://www.rossow-web.com/diamond2.jpg

Any help would be great.
.roy.

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# 2 14-08-2009 , 07:34 AM

Maniacal boy king of Babylon
Join Date: Aug 2005

Location: the netherlands

Posts: 1,605

" Not sure if this is a Mental Ray or not..."
-check your rendersettings LOL

You probably have lit the scene with FG or GI, so it's probably the quality of that or the number of sampels have to be higher.
Regarding the dark areas in the diamond this has to do with the amount of photon's you have in the scene up the number of photons emitted by your image/light and maybe even up the photonintensity by a hair user added image

My website;
https://www.eyellem.com

LinkedIn:
https://www.linkedin.com/pub/martin-van-stein/42/a81/b82

Yoda post;
https://forum.simplymaya.com/showthre...highlight=yoda

Indiana Jones Post;
https://srv01.simply3dworld.com/showt...threadid=29188

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# 3 14-08-2009 , 07:35 AM

Maniacal boy king of Babylon
Join Date: Aug 2005

Location: the netherlands

Posts: 1,605

Oh and you need to increase the amount of "lightbounces" so more reflect/refract rays

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# 4 14-08-2009 , 05:08 PM

Super Moderator
Join Date: Dec 2006

Location: South FL

Posts: 3,522

Originally posted by rasta3d

> Why am I am getting so much grays, and not enough strong darks and lights?

Originally Posted by

You're getting a lot of grey because the backdrop has a lot of grey. If refractive surfaces don't appear as transparent as they should then you need to check a few things

*Under raytracing in the render settings, make sure there are enough refractions being traced, and that your max trace depth can keep up with both the reflections and refraction tracing.

Check out my cheesy text version of the MR render settings below user added image

Reflections [ 2 ] --|---------
Refractions [ 6 ] --------|----
Max Trace Depth [ 8 ] ----|--------

8 maximum traces is enough to cover 2 reflection bounces + 6 refractive bounces.
Same thing for the Shadows settings, default its set to 2, so shadows will not be calculated through more than 2 surfaces which means you won't be able to see the shadow of an empty glass when looking through the glass.

Same thing with the photon tracing settings and Final Gather tracing.

Originally posted by rasta3d

> Why isn't my gradients nice and smooth? If you look closely, there seems to be something like dithering going on.

Originally Posted by

You're shadows are probably noisy because the samples on your light (s) are too low.