Hi, I got a strange behaviour when using transparency in VRay:
I use a png for the diffuse color and checked the option “diffuse texture alpha” to get the alpha values from the png. It works, but when I render this material in front of a darker material, there always is a white border. How can I avoid this?
I tried also a png without transparency plus additional black/white transparency map - same issue.
Maybe the transparent area is to small and the soft anti aliasing cause that the background color from the PNG is visible. Do you get a white seam if you use the transparency map, but you use a green color instead the texture at the diffuse slot?
Hi,
I think when you create your image with an alpha channel you get a choice of Prematted or Straight.
This is what causes your white edges.
More info here
Are you sure the info is valid for PNG? I never have seen an option for prematted or straight. Is there an option for example in Photoshop?
A Generic material with the transparency map shows the same white border:
I found a way to avoid this issue:
Create a Generic material (1) with the png as diffuse color
Create a Generic material (2) and change the opacity to “0”, so the material is invisible
Create a Blend material: use the invisible material (2) as base material and material (1) as coat. Use the transparency map as blend map.
That is the result:
Does anyone understand, why there is a white border when using a map on opacity, but no such border, when I use the identical map as a blend map?
How doe’s it look if you use no PNG at the diffuse slot, only a red color?
I did a check. Solid color is no problem:
Looks like the background color of the transparent area is visible at the edges:
I see two ways to fix it - create a transparecny map where the transparent area is larger or add an other background color at the diffuse texture. I would try to make it green.
Thanks for your effort Micha!
I tried it with a solid color (no png involved), it is the red one above → white border. And the transparent area is quite big, making it bigger should not have any effect.
For now, my solution seems to be the blend material, even if I don´t understand what is going on exactly.
Strange. So we have two different results. Could you post an example file?
Changing the mode of the opacity map from stochastic to clip fixed it. Thanks!
