VRayBRDF-Diffuse Texture Alpha

[KPSWD]

My models are generally landscapes/gardens and use a lot of face-me components which are usually PNG format files. We have a large library purchased from CADPlants and we make our own in house

in either PNG or PSD

. I am finding with VRay 3 that the transparency of these components is unreliable. Sometimes the transparent areas appear white and sometimes there is an irregular black border between the image and the transparent areas.
Both of these issues are generally fixed by turning on Vray BRDF >Opacity > 'Diffuse Texture Alpha'.
But what I don't understand is why this is necessary when it wasn't with VRay 2, and why it seems some components have this setting on by default and some need to have it set by me when they all appear the same image format? Is there some way I can create face-me components that will have transparency rendered correctly without editing the material in VRay?

Thanks...

[matthewg]

Hey,

The issue seemed to occurs for us when you copy components from a model created in vray2 to a model using Vray3 (It would show up OK in the viewport but render with white or black where it should be transparent) My guess when it converts to a vray 3 material it doesnt take the information that it has an alpha across with it and therefore the diffuse texture alpha was turned off?

The other way it would occur is when you create a new generic material (which has the diffuse texture alpha turned off by default) then add the diffuse texture afterwards. To be honest, i think this is working as intended?

To get around the issue and improve our workflow we started dragging the .png direct into the viewport holding Alt (Windows) when clicking on the face to apply it too. I don't know if this is the best way to do it, but it worked for us. It created the material in Vray asset editor with the Diffuse Texture Alpha turned on by default.

Hope that helps or if not i hope someone else can come up with a solution for you.

Regards

Matt

[Peter.Chaushev]

The discrepancy you have noticed is between outdated v2.0 and the current v3.6 materials.
Some of the material plugins used in V-Ray 2 are no longer used, due to compatibility issues, limitations in their ability to be further developed, etc. While they are still supported, to achieve the exact same result, sometimes manual editing is required, e.g. alpha map adjustment or texture gamma value change.

Matthewg's comment describes the workaround. In most cases, Diffuse Texture Alpha is sufficient to resolve .PNG opacity issues.
Regarding the dark outline you've mentioned, it may be due to the quality of the .PNG image. Could you please confirm whether it renders the same way in all 3 Opacity modes?

Kind regards,
Peter