I tried to render some objects with fully transparent regions inside a volumetric region and discovered that where the objects are supposed to be transparent, the background is seen trough. In the attached scene the color texture is mapped normally to COL and the alpha map (black where the object must be opaque, white where transparent) is mapped to ALPHA and NORGB. The glitch is visible the most when the transparent object is in front of the volumetric region and gradually fades out as the object moves behind the volume.

In the scene the leftmost leaf is behind the volumetric region, the middle is inside and the rightmost is infront.

Software used:

- YafaRay 0.1.1 (431)

- Ubuntu 9.10 64

- Blender 2.49b

The attached .blend file contains packed textures.