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View Full Version : How to get Dielectric to render properly?



svintaj
05-14-2007, 08:58 AM
I'm trying to use dielectric but get bad results, so what's the secret trick?
This is my best results: ;D

Using the switch node to hit air/inside: (Broken shadow?)
http://www.segelson.com/Temp/Dielectric_BadShadow_Switch.jpg

And using polygons to hit air/inside: (Ugly black ring on the shadow edge?)
http://www.segelson.com/Temp/Dielectric_BadShadow_AirPolys.jpg

And here is the scene file:DielectricTest.zip (http://www.segelson.com/Temp/DielectricTest.zip)

Thanks in advance!:lwicon:
/ Svante Segelson

jameswillmott
05-14-2007, 09:17 AM
Does your dielectric surface have Double Sided switched on?

Bytehawk
05-14-2007, 09:19 AM
have a look at this object, the default surface has dielectric

svintaj
05-14-2007, 09:54 AM
Thanks but nope Bytehawk, still get bad shadows:
http://www.segelson.com/Temp/AlsoBadResult_01.jpg

JamesWillmott, yes it's double sided.
Hmm, am I the only one with this problem?

/ Svante

Dodgy
05-14-2007, 10:29 AM
Works for me...

jameswillmott
05-14-2007, 10:33 AM
Nope, I get the problem too with your scene. Weird...

svintaj
05-14-2007, 10:36 AM
Works for me...
Cool, can you maybe post a working scene?

/ Svante

parm
05-14-2007, 10:59 AM
It works when I sub-patch the ball. But get the same result as you with smoothing only.

Could be a bug

Bytehawk
05-14-2007, 11:09 AM
ray trace reflection, transparency, etc. everything is on ?

Dodgy
05-14-2007, 11:32 AM
In that case could it be a nonplanar poly problem? Try tripling your polys?

svintaj
05-14-2007, 11:56 AM
Yes Bytehawk all raytracing is on exept the new Raytrace Occlusion.

It works when I sub-patch the ball. But get the same result as you with smoothing only.

Could be a bug It does not work for me even if I sub-patch it!?

But now I bet this is a bug, try to rotate the object around, then render and see what's hapening:

It seams like the shading is kind of "sticky aplyed in object cords" and if you rotating it back, previus hiden areas do not render the shading at all?
Totaly crazyness!?

Look at this animation (http://www.segelson.com/Temp/DielectricTest_A.MOV)where I just spin the object one orbit(360 degrees)
Notice how the Dielectric shading disappear!?

/ Svante

parm
05-14-2007, 12:04 PM
Sorry svintaj. I also raised Render Sub-Patch level to 6 in the object properties panel

Bytehawk
05-14-2007, 12:08 PM
Svintaj, could you please send in the scene and a small description to

[email protected]

that way a technician can take a look.

svintaj
05-14-2007, 12:09 PM
In that case could it be a nonplanar poly problem? Try tripling your polys? Yea, I have done that but it didn't solve it.

And Parm, I actually raised it to 10, but the black edge where still there, a bit thinner though...

/ Svante

svintaj
05-14-2007, 12:11 PM
Svintaj, could you please send in the scene and a small description to

[email protected]

that way a technician can take a look.

Good idea I will do that.
Thank you all!
/ Svante

parm
05-14-2007, 12:48 PM
I think the black edge is just the shadow colour of your light. Try chnging it to a blue colour to blend in better.

Captain Obvious
05-14-2007, 01:19 PM
Looks like a smoothing error to me.

svintaj
05-14-2007, 01:26 PM
I think the black edge is just the shadow colour of your light. Try chnging it to a blue colour to blend in better.

That is a decent workaround, another one is to blur the shadow with an area light.
But how about that weird animation...?;D :help:

/ Svante

RedBull
05-14-2007, 09:06 PM
Interestingly, FPrime renders the scene correctly, but LW does not.