Announcement

Collapse
No announcement yet.

Issue using "noise" as reflection map (possible bug)

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Issue using "noise" as reflection map (possible bug)

    There appears to be an issue with using "noise" as a reflection map in VRSU and Material Studio. The black and white areas of the noise map are not recognized as reflective and non-reflective areas. The white areas of the noise are 100% reflective (as they should be), but the black areas of the noise seem to be producing bright white specular highlights (these areas should be completely non-reflective).

    As an example for comparison:
    - In the material studio create a new VrayMtl
    - Add a new reflection layer to the material.
    - Under the reflection rollout Click on the reflection map slot.
    - Change the reflection map from "fresnel" to "checker"
    and set the u and v repeat values to 2 and apply.
    - Update Preview

    See how the white checkers are 100% reflective and the black checkers are non-reflective. This is correct. All maps containing areas of black and white should behave this way. The noise map however does not.

    As an example:
    - In the material studio change the reflection map from "checker" to "noise"
    and set the u and v repeat values back to 1
    - Click update on the preview to show the noise pattern (should look cloudy).
    - Now set the bias to a higher number, say... 128.
    - Click update on the preview again. There is now distinct white and black areas.
    - Set the noise size to 12
    - Click apply
    - Click "update preview" to render

    See how the white areas of noise are 100% reflective and the black areas show up as bright white hot spots. This is incorrect, the black areas should be non-reflective. I've also tested this using a bitmap of a noise pattern with black and white areas. It worked correctly with white areas showing up 100% reflective and black areas 100% non-reflective. So there is an issue with the "noise" map.

    Is there any reason that this happens and is there a way to resolve it? Or is it just a glitch, perhaps to be fixed in a later release? ;D

  • #2
    Re: Issue using "noise" as reflection map (possible bug)

    Hmm - I'm not sure why that would be. I'll add it to our list to check out.
    Best regards,
    Joe Bacigalupa
    Developer

    Chaos Group

    Comment


    • #3
      Re: Issue using "noise" as reflection map (possible bug)

      Just guessing here but could it be that the noise shader somehow have negative black values "below zero"? That might cause some weird things to happen.
      I've experienced that with Maya's noise shader.
      Then something like this might fix it: if(black < 0) black = 0;

      Comment

      Working...
      X