I’m attempting to use the Alpha Transparency feature but it seems like no matter what I have toggled on/off, none of my materials are masked out in the alpha channel. The only success I’ve had is turning off the ground plane and in the Rendering panel, toggling the Transparent Background option on. This, however, is not always ideal. In my example file, if I wanted to mask out specific parts of my ring, I’m unable to do so. Please let me know if I’m doing something wrong. File attached.
This is not going to work. The background transparency with ground plane disabled is needed for the alpha channel to give you anything useful.
The alpha transparency button you are trying to use in the material GUI for Rhino Custom material is for using of alpha channel from texture map in the color channel as cutout value for the object.
For Rhino 8.5 I added object and material id pass support. In the Render Window it needs a bit of tuning still by @DavidEranen to both look correct and save out correctly.
But that should give you a pass that you can use in compositing to mask out parts of your objects.
Perhaps the Albedo channel could already do this for you.
Gotcha. I’ll keep an eye out for that 8.5 release. In the meantime, I can take a look at the Albedo channel and see what kind of results are possible. Thanks for the quick response.
Ah, the Albedo channel works properly only in 8.5, since prior to that selecting that didn’t work properly.
Wednesday you should be able to install Rhino 8.5 as a service release candidate. Set the update frequency to Service Release Candidate through Help > Check for updates…
@nathanletwory I was hoping I’d be able to figure out how to make use of the Albedo setting. Would you be able to show an example of a setup that makes use of the Albedo channel? Based on the documentation below…
After a bit more playing around, I found out why my Albedo channel yielded no results. It’s a toggleable option in the Rendering panel. After toggling it on, any objects that have a non-default material applied receive a black “fill” in the Albedo channel. Everything else shows up as white. There does seem to be a lack of antialiasing (at least in the build I’m running) but it’s rather nice to have this as a potential masking option.
With regard to the Albedo documentation, it didn’t seem like I had to make any changes to the lighting and shadows. And when I did, there were no noticeable changes in the Albedo channel in the render window. Hopefully, this info is useful for anyone else following this thread.
FYI, albedo will give you what in Cycles is the DIFFUSE_DIRECT pass. You have a metal material on three of your spheres, and therefor will not give anything but black.
The rest show white because they have the Rhino default material assigned, and that means they all are white. If you were to assign a plaster with red color you’d get that object as just the flat red.
