View Full Version : Major render errors with refraction blur

Thomas M.
06-21-2007, 03:48 PM
As I need to go for very real glass I wanted to make use of the refraction blur and dispersion. I started using the dielectric material with a switch for front-/backside. The air surface does have an IOR of 1.0 and no reflection nor refraction blur activated. The settings of the glass surface can be seen in the attached file.

The problem is that refration blur doesn't work correctly. The amount of samples isn't any longer responsible for the quality, but somehow for the darkness of the object. Even if there isn't anything dark in the ground nor the reflection map. The brightness should stay like if refraction blur wouldn't be activated (upper image sample), while being slightly blurred.
Setting the blur to 0.001 doesn't make a difference. This only happens if you activate the refraction blur check box.

What can also be seen is that the reflection of the total inner reflection is disappearing more and more depending on the amount of samples.

What's going on?

Since there are still severe bugs in Kappa II (Case 5210: When is this going to be fixed?), I wouldn't be surprised if this is a program error and not a user mistake (myself).

The object has doubled-sided checked on, doesn't have "real" air polygons, all raytracing function are enabled, 16 rays, etc.

I don't know what it can be. Can somebody please confirm?

Going for a standard node which mimics the dielectric node doesn't make a difference. It's still getting dark. NO ABSORPTION is enabled. At least not by me (probably internal?).


06-21-2007, 04:03 PM
Have you run all of your tests using F9 renders as well as in FPrime ? As I have already discovered, FPrime does not always render Dielectric surfaces exactly the same as LW and F9. All your examples use FPrime Preview so it might be worth doing a little extra testing

06-21-2007, 04:18 PM
Can you post a setup? I can't replicate this...

Thomas M.
06-21-2007, 04:24 PM
I'm just rendering pure LW images. 320 by 240px takes more than 20 minutes to render, but I'm getting afraid that it is a fPrime bug, as the darkness isn't there anymore and it looks correct. Would be horrible, as it is impossible to render anything with a decent pixel size in LW.