# Rendering with alpha channel

**URL:** <https://discourse.mcneel.com/t/rendering-with-alpha-channel/8574>\
**Category:** Rendering\
**Created:** [May 22, 2014, 2:22pm UTC](https://discourse.mcneel.com/t/rendering-with-alpha-channel/8574 "2014-05-22T14:22:39Z")\
**Posts on this page:** 11\
**Page:** 1

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**Author:** ![hkalmus](https://avatars.discourse-cdn.com/v4/letter/h/71e660/32.png) [@hkalmus](https://discourse.mcneel.com/u/hkalmus)\
**Post date:** [May 22, 2014, 2:22pm UTC](https://discourse.mcneel.com/t/rendering-with-alpha-channel/8574/1 "2014-05-22T14:22:39Z")

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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

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**Author:** ![John\_Brock](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/john_brock/32/476283_2.png) [@John\_Brock](https://discourse.mcneel.com/u/John_Brock)\
**Post date:** [May 22, 2014, 2:34pm UTC](https://discourse.mcneel.com/t/rendering-with-alpha-channel/8574/2 "2014-05-22T14:34:36Z")

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

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**Author:** ![BrianJ](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/brianj/32/751593_2.png) [@BrianJ](https://discourse.mcneel.com/u/BrianJ)\
**Post date:** [May 22, 2014, 2:35pm UTC](https://discourse.mcneel.com/t/rendering-with-alpha-channel/8574/3 "2014-05-22T14:35:56Z")

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Here’s a screenshot too…

 ![](https://global.discourse-cdn.com/mcneel/uploads/default/original/3X/e/b/ebde9a97bc162ef3e5a66f85168281581857d4d8.png)

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**Author:** ![declan](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/declan/32/481847_2.png) [@declan](https://discourse.mcneel.com/u/declan)\
**Post date:** [July 17, 2014, 6:44pm UTC](https://discourse.mcneel.com/t/rendering-with-alpha-channel/8574/4 "2014-07-17T18:44:16Z")

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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!

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**Author:** ![BrianJ](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/brianj/32/751593_2.png) [@BrianJ](https://discourse.mcneel.com/u/BrianJ)\
**Post date:** [July 17, 2014, 7:09pm UTC](https://discourse.mcneel.com/t/rendering-with-alpha-channel/8574/5 "2014-07-17T19:09:16Z")

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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?

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**Author:** ![declan](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/declan/32/481847_2.png) [@declan](https://discourse.mcneel.com/u/declan)\
**Post date:** [July 18, 2014, 6:57pm UTC](https://discourse.mcneel.com/t/rendering-with-alpha-channel/8574/6 "2014-07-18T18:57:20Z")

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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 ![](https://sea3.discourse-cdn.com/mcneel/uploads/default/10878/0420fb148bcc583c.jpg) ![](https://sea3.discourse-cdn.com/mcneel/uploads/default/10879/cdf2ef93396cc48d.png) iewport?

Thanks!

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**Author:** ![BrianJ](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/brianj/32/751593_2.png) [@BrianJ](https://discourse.mcneel.com/u/BrianJ)\
**Post date:** [July 18, 2014, 7:10pm UTC](https://discourse.mcneel.com/t/rendering-with-alpha-channel/8574/7 "2014-07-18T19:10:49Z")

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> [@declan](#):
>
> Is there a way to get an alpha channel using just Print\>PNG, or CaptureV

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.

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**Author:** ![declan](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/declan/32/481847_2.png) [@declan](https://discourse.mcneel.com/u/declan)\
**Post date:** [July 18, 2014, 7:30pm UTC](https://discourse.mcneel.com/t/rendering-with-alpha-channel/8574/8 "2014-07-18T19:30:47Z")

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

Cheers,

dh

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**Author:** ![declan](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/declan/32/481847_2.png) [@declan](https://discourse.mcneel.com/u/declan)\
**Post date:** [August 22, 2015, 5:55pm UTC](https://discourse.mcneel.com/t/rendering-with-alpha-channel/8574/9 "2015-08-22T17:55:58Z")

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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

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**Author:** ![BeeCee](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/beecee/32/650094_2.png) [@BeeCee](https://discourse.mcneel.com/u/BeeCee)\
**Post date:** [August 25, 2015, 12:36pm UTC](https://discourse.mcneel.com/t/rendering-with-alpha-channel/8574/10 "2015-08-25T12:36:54Z")

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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?

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**Author:** ![declan](https://sea3.discourse-cdn.com/mcneel/user_avatar/discourse.mcneel.com/declan/32/481847_2.png) [@declan](https://discourse.mcneel.com/u/declan)\
**Post date:** [August 29, 2015, 8:15pm UTC](https://discourse.mcneel.com/t/rendering-with-alpha-channel/8574/11 "2015-08-29T20:15:28Z")

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That’s great to know what the multiplier does! 😉

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.