Rendering with alpha channel

Rendering
1

I"m attempting to render an object, Rhino default renderer and default lighting, no background and an alpha channel. I’m finding no option to render with an alpha although I do see the “show alpha” button in the render window. How do I do this? Thanks

2

Rhino Options - Rhino Render - Cleck Transparent background.
Then Render and save as a PNG file

3

Here’s a screenshot too…

Pasted image628×549 64.1 KB

4

Hmm… I’m trying to do the same thing and it’s not working.

  1. I have Auxpecker 2.0 installed, but the Background is not active (Slider turned off).
  2. Viewport Display Mode is set to Rendered, not Auxpecker.
  3. Current Renderer = RhinoRender.
  4. Options/Doc Properties/Rhino Render > Background = Transparent.
  5. I am using .png or .tif format.

My viewport has a solid black background, and so does my ‘printed’ .png file.

Any suggestions? I really need to get this sorted out…

Thanks!

5

I don’t have Auxpecker here but if it’s not active as the Display Mode on your system I’m not sure how it would play a part in this. Have you tried disabling the plugin as a test anyways? If it still doesn’t work, can you share the file or a portion of it?

6

Ok - I found the problem. I was trying to use Print to export the viewport as a png. This method ignores the “transparent background” options.

If I do a formal Rhino Render, and save as png, I get the transparent background. Unfortunately, I don’t want to run the Render engine, as Auxpecker already has eMaps applied that look pretty good. See attached for the difference.

Is there a way to get an alpha channel using just Print>PNG, or CaptureV iewport?

Thanks!

7

Use “-ViewCaptureToFile” and change the transparent background command line option to yes. This should work for you if there’s nothing under the model like a ground plane.

8

Awesome! Thanks Brian, that works great. The Command Line interface is a little clunky, but it works!

Cheers,

dh

9

Just to followup, I find myself using this pretty frequently. Is there any plan to streamline this process? I ask because the command line offers Width/Height resolutions, but

a) I am not sure of the ideal aspect ratio
b) I often could use a draw-window similar to the print command.

Thanks again!

Dec

10

The aspect ratio appears to default to your viewport ratio. The “multiplier” option then scales the resolution by that ratio x the scale multiplier you type in. If I want a specific resolution (ie. 4:3 or whatever) I think you have to do the math manually first.

I believe in Vray you can bring up a red square that shows the render preview space? Is that what you are thinking of?

11

That’s great to know what the multiplier does! :wink:

I’m not familiar with Vray, so I can’t speak to that preview, but I might not need to render the entire viewport, so I would like to draw a window around just the relevant area.