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reflected light questions

Posted: Thu Mar 20, 2008 12:29 pm
by fulvio
My question is about noise of reflected light and how can I reduce, if is possible, the time render.

The first image "test.jpg" is render with some material problem, than I've used to see the global light result and correct the error.
The main problem was the noise of reflected light near JDC logo that is visible in "test-part.jpg"

This is my kray settings
Photons preset - medium (photonmap, emitted, multipler 4.0)
FG preset -low
Sampling - medium grid 3
Quality preset - medium but with luminosity threshold 0,01 - min100, max1500 (reflec/refract min100, max1000)

Image resolution 2048x1536
Time render about 13h

In the scene there are 50 poly light (part with autopart plugin) and 7 lw light.

I've tried to activate the "trace direct lights reflections" (to try to resolve the noise of reflected light) and the result is the image "def.jpg" .... but about 28h at 2048x1536 resolution.

In the image lw_ligt and poly_light there are my light setup.
Can You help me with some advise for kray settings ??

Thanks

Posted: Thu Mar 27, 2008 10:03 pm
by jure
I'd use less reflection on the wall and turn down max rays for refl/refr blurring accuracy limit (100-200). There also might be issue with bump causing those specks.

I also wouldn't use lumi polys to light this scene. Spot lights should work just fine. Try to simplify your lighting.

Also.. what are those linear lights?

Posted: Fri Mar 28, 2008 11:02 am
by fulvio
jure wrote:I'd use less reflection on the wall and turn down max rays for refl/refr blurring accuracy limit (100-200). There also might be issue with bump causing those specks.

I also wouldn't use lumi polys to light this scene. Spot lights should work just fine. Try to simplify your lighting.

Also.. what are those linear lights?
Thanks for Your reply.

I'd not much time for this work and I've used poly light for fast (light) setup.
For the best render speed, when it's possible it's better to use spot light instead of poly ??

Linear light is for simulate neon above tube of air-conditioner.

Now I try to setup the scene with spot light and to change the brick bump map and to lower the refl/refr settings but, when it's right to use "trace direct lights reflections" ??

Thanks

Posted: Fri Mar 28, 2008 12:11 pm
by jure
pixeldust wrote: I'd not much time for this work and I've used poly light for fast (light) setup.
For the best render speed, when it's possible it's better to use spot light instead of poly ??

Linear light is for simulate neon above tube of air-conditioner.

Now I try to setup the scene with spot light and to change the brick bump map and to lower the refl/refr settings but, when it's right to use "trace direct lights reflections" ??
Use spotlights when your lightsource is small. This way you can stay in indirect render mode. Once you add luminous polygons you must switch to direct mode.

Trace direct lights reflections allows point and linear lights to be visible in blurred reflections (similar to specularity), also area and lumi lights are sampled like direct lights with the same pros/cons.

Posted: Sun Mar 30, 2008 6:17 pm
by fulvio
Thanks Jure, Your advice are very useful.
I've used lw spot light and this render is better of my previous ...

I do some other test .... thanks.