Visible to camera issue

[Stirling]

I'm having the same issue that was described in this post from back in 2014: https://forums.chaos.com/forum/v-ray...-to-camera-bug

I'm using a Forest Pack object to scatter some vegetation, then unchecking 'Visible to Camera' just to get the shadows. The problem is that it produces some strange alpha issues (like the attached image), presumably where there are collisions in the Forest Pack object. The fix in the above post was to turn off Embree but I can't see that as an option in the latest version of VRay.

Is there a way round this? The render slows right down on those particular bits.

[garipodelu]

Try to increase Max trasp. levels. Vray tab > Global switches and see if this helps.

[Stirling]

Thanks for the advice. It worked but I had to raise the max transparency beyond 500 to make an impact and even then it wasn't completely clear

[^Lele^]

With opacity mapped foliage, you may have to raise it even further, depending on how dense it is (as the rays will have to cross more opacity mapped planes the denser the vegetation is.).
You would get some massive performance increase, at the expense of more memory usage, if you made those leaves opaque polygon meshes.
Opacity and raytracing were never good friends.

[Stirling]

Good to know, thanks Lele

[fixeighted]

It's a very interesting 'about-face' (unintentional though witty pun) in rendering.
Unfortunately a great deal of the available assets still rely on opacity.
Life's challenges are ever-changing