transparency extremely slow

[sharktacos]

We have a tree which has a large number of leaves using opacity maps. The render times are very slow, and this seems to be caused by the opacity/transparency. We have noticed the same thing when using cards to simulate background trees. Is there a way to speed this up in vray? These are old gaming tricks that normally would speed up a render, but it seems it is making it especially slow in vray.

[bigbossfr]

Hi,
Can you disable the filtering on the opacity map ?

[sharktacos]

Filtering is off.

[Ekenryd]

Also, make sure your alpha-maps are only black and white, no shades of grey, it has the same speed-drain as filtering.

[griml0ck]

If there was an option to make the objects "opaque for GI" like you do in the new hair shader, it would make your renders a lot faster. Could be a smart solution if it was implemented. I asked about this before, it would be good if this option was exposed in the vrayobjectproperties node for example. So you can render hair with other shaders than the vray hair shader and still get good performance with transparency.

[vlado]

Filtering is off.

How did you turn it off? If you just selected "Off" for the filtering option of the file node, it will indeed turn off filtering, but not interpolation so there will still be some slowdown. In the latest builds, you can add V-Ray filtering attributes to the File nodes - make sure that filtering is turned off there, so that the mask is pure black or white.

Best regards,
Vlado