Cineversity

I cant seem to get any grayscale values in a viewport renderer alpha channel. Is that the case? Standard renderer works fine as usual but I need the speed of a viewport render.

I’ve attached 3 images (scaled 200%)

RGB = screen grab of the viewport
Viewport alpha
Standard alpha

I’m working on a Mac with latest version of all software / OS.

Thanks

Hi mtb_dude,

I assume you use the “Interactive rRender Region”, and those results are dependent on all other settings as with the Picture Viewer render results.

If no Anti-Alias is enabled, then your result might (but mustn’t) look like that.

Alfa information can be quite acceptable, though the results of the editor view are different from the Picture Viewer. You won’t get all features or qualities from it. This is not listed in the manual.

https://help.maxon.net/c4d/s24/en-us/Default.htm#html/OSNIPER.html#PLUGIN_CMD_430000021

Test this scene. I get from an Interactive Render Region result a nice Alpha channel.
https://www.amazon.com/clouddrive/share/GM3fnAkmcUUXmcGJiH5xdBgM85zjUNKssFOsMIpZXgs

All the best

I haven’t used the IRR on this project. All results are from the picture viewer and the rendered file of course. The editor looks great but in the end I need a render that I can composite over a background of choice in After Effects. Here is what the picture viewer shows of the file you linked to. Like you mentioned, may not be supported in an actual render (yet
Thanks!

https://drive.google.com/file/d/1c-QJazE3_Ry1axtXCvh-IaWD3bF9vPWB/view?usp=sharing

Interestingly, no alpha will be generated unless you actually save the file to disk.

Thanks for clearing that point, mtb_dude.

Yes, that render is a footnote in my training and never on my mind. The alfa information that you get from the IRR is at least complete, even not hi-end either. Having said that, I explored it based on your needs, just in case things might have changed. As before, I’m not a fan of that options for compositing.

Got it; I never thought that anyone would use it for anything outside of a quick check of concept inside of C4D. But well, the last artist who used this Quality was from the expression college in Emeryville, and she ( a director of that college and motion artist) used all the parts in it, grid axis, etc. As a unique way of using an aesthetic that anyone else avoids around ten years ago. Since then, I haven’t had a single question here.

After a few seconds, an alpha preview appears here, but quite frankly, that is not at all at any time what I would suggest for any production.

The alpha channel here shows a vivid ignorance of transparencies, and the alias settings are far from the standard render options. You have no option to get any adaptive control. Anyway. I have no idea what project you are aiming for. It sounds like a previsualization quality to me.

I can’t suggest using this in Ae, as I think it is a bad idea, but then again, I have no clue about your needs.

If it is anything for quality compositing, I suggest to used floating-point and straight alfa Standard or Physical. Viewport doesn’t provide Straight Alpha; if you compare both qualities (A/B difference), there is no sign that anything would have changed, either way, what setting was used.
No-straight will limit your options in terms of corrections of the total values of the pixels around the “edges”. You might be aware of that, but I try to be precise as I write in a forum.

Cheers, and good luck with the project.

Thanks for the feedback Dr. Sassi. This is the first time I needed an alpha from a viewport render. It’s for pre-viz purposes but I was hoping to do a quick comp up in AE. There’s been a lot of work done on the viewport in recent versions and maybe we will see better alpha outputs in upcoming versions.

Thanks for the extra information, mtb_dude,

The fastest way to get a pristine Alpha would be to go Standard Render. Then create a new Material and check all the channels of that Material to off.
Then in the Render Settings, activate the Overwrite Material, and apply this black Material to the option given for the overwrite.
The resulting rendering with alpha enabled should give you a nice Alpha pass.

I have limited information about your setup, so please run a test first.

Alternatively, the Compositing tag has a Matte Object option. Which allows disabling the surface qualities but leaves the objects in the scene. With different colors of that option, you can create even a multiple color object map to key the masks you might need.

All the best