Max Depth with Opacity maps?

[jpdrude]

Dear Community,

I am having an issue here that has now been grinding down my nerves for the second day.
I scattered some planes in Grasshopper and created a billboard material with some grass on it to get nice foreground grass leaves in addition to a 2d-displacement grass material lying underneath.
The trouble is that everything in the background becomes black, or rather alpha. It feels as if there was a max depth option somewhere buried within the settings that I cannot access, thus skipping to an exit color, after the ray has passed the nth plane.
If rendered on GPU it works fine, but there the 2D-displacement doesn't work.
Has anyone any experience with this issue, or can I tell me if I can get to this value through scripting or a config file or anything? Or maybe I am on the wrong track entirely?
Would be great for someone to chime in here.

Thanks in advance,
Jan Philipp

PS: It seems to be the same in 3ds-max.

[natali.velcheva]

Hello Jan,

Thanks for your post. Could you please tell what version of V-Ray you are using and also archive the scene you are working on and share it with us? This can easily be done by using the V-Ray menu > Pack Project. You can send it at support@chaosgroup.com through a file-sharing service of your choice.
Once we investigate it we will be able to assist you further.

Kind regards,
Natali

[natali.velcheva]

Hello, Jan,

As I already mentioned by email, the parameter you need to update is Opacity Depth https://docs.chaosgroup.com/display/...+Anti-Aliasing. It is exposed in Settings > Raytrace (Advanced view) > Optimizations > Opacity Depth. Try increasing the value to 100 or whatever fixes the issue based on your camera position.


Kind regards,
Natali

[konstantin_chaos]

HI Jan Philipp,

The parameter that Natali pointed out will certainly help.

On the other hand, keep in mind that big opacity depth value will slow down rendering quite a bit.
V-Ray is often times better at rendering huge number of polygons compared to many transparent surfaces.
I would recommend you use V-Ray Fur or even scattering proxy grass strands with no opacity in the material.

Regards,
Konstantin