Rendering bugs on 9t3 ? See samples...

Strykaas · Post by **Strykaas** » Sun Aug 19, 2007 2:32 am

OK Ono, I'll look into that direction

suvakas · Post by **suvakas** » Sun Aug 19, 2007 2:54 am

zsouthboy wrote:Normal smoothing.

Period.

You're an idiot for insisting otherwise.

Yeah, but what if you don't want them smoothed?

I still think it's because of how each face reflects/refracts it's surroundings a bit differently from others cause of it's angle.

Kram1032 · Post by **Kram1032** » Sun Aug 19, 2007 3:04 am

If you don't want it smoothed, you can't fix that anyway - I think, not even the geometry is wrong.... It's simply 'cause of off normal smoothing.

suvakas · Post by **suvakas** » Sun Aug 19, 2007 5:19 am

Here is a render with normal smoothing off and IOR set to 1.03
As you can see there are no such reflections.

Strykaas · Post by **Strykaas** » Sun Aug 19, 2007 5:45 am

Interesting.

Kram1032 · Post by **Kram1032** » Sun Aug 19, 2007 8:20 am

The material isn't much denser than air, though. Light falls through it, nearly straight.

Strykaas · Post by **Strykaas** » Sun Aug 19, 2007 8:36 am

For yourknowledge, glass is around 1.50. I'll keep it there.

Kram1032 · Post by **Kram1032** » Sun Aug 19, 2007 8:39 am

Glass:
IoR Between 1.3 and 1.9
(window glass ~ 1.52, usually, lead glass ~1.7-1.9)
cbc (cauchy b's coefficient) 0.029-0.04, more or less 0.03

suvakas · Post by **suvakas** » Sun Aug 19, 2007 9:07 am

If you want to make glass and use faceted geometry, then these funky reflections is what you get I'm afraid.
You could try to model those faces separately with thickness. That may also help.

CTZn · Post by **CTZn** » Sun Aug 19, 2007 12:29 pm

If you want to make glass and use faceted geometry, then these funky reflections is what you get I'm afraid.

Mmmh maybe if the geometry output data is corrupt, as suggested Ono. I'm prone to second his opinion, telling normals are incorrect. Seems obvious to me when comparing the two cylinder images, first image may be concerned too, dunno.

Strykaas, what modeler/exporter do you use ?

Strykaas · Post by **Strykaas** » Sun Aug 19, 2007 8:39 pm

I used Blender 2.44 + Blendigo exporter for 9t3. I carefully re-computed normals before rendering. Actually, those two shapes are extruded surfaces. Maybe there's an issue with them, but I'm dubious as these are basic features of Blender. Anyone can try, it's a five minute operation...

suvakas · Post by **suvakas** » Sun Aug 19, 2007 8:53 pm

I got similar "strange" reflections from cylinder made in 3ds Max. I used the same cylinder to make that low IOR rendering. The geometry is fine.

Strykaas · Post by **Strykaas** » Sun Aug 19, 2007 9:00 pm

suvakas wrote:I got similar "strange" reflections from cylinder made in 3ds Max. I used the same cylinder to make that low IOR rendering. The geometry is fine.

Interesting too.

Kram1032 · Post by **Kram1032** » Mon Aug 20, 2007 4:09 am

I still think, every thing's fine.

try to get that in reality - if you'd use absolutely straight, unbevelled Edges, with the same sun light situation, you'd see the same things.
It might help, to bevel the edges, a bit (and then use normal smoothing)

Rendering bugs on 9t3 ? See samples...

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