standart Max Material with opacity map: 51 sec.
Vray Material with opacity map: 67 sec.
Vray Material with the same map in refraction map slot (ref. index 1): 56 sec.
I did this test on some speedtree scenes too and was a little shocked. A scene with 2 hour rendertime was at 4.5 hours.
Ok, it’s a first step. Unfortunatly it’s not worth a cent at the moment as it’s slower then before. Hope this will get improved.
One hint for using TGA files: Vray interpret the Targa different, so you can’t just instance the material from diffuse slot. you have to turn alpha as grey on.
this opacity slowdown is really a pain in the +++…anyway i m using norwadays a blend material with a vray mat with the difuse map and the opacity map in the mask slot…it seems a workaround…
Robert, it would be nice if you can send this quick test to me at vlado@chaossw.com; my own tests indicate that VRay opacity is faster that the std material in all cases I’ve made so I would like to take a look at your scene.