Background bitmap - adjusting transparency level possible?

Is it possible to adjust the transparency level of a background bitmap in Rhino for Mac?
I cannot find such settings in the command “BackgroundBitmap” menu.

I do like to work in a hybrid workflow, doing sketches on top of a background bitmap, printing a screen grab, drawing, marking and noting with pen on the paper print out and then continue work.

I would like to set the transparency level of the background printout, so the actual image is not that dominant in the print.

Any tips or workarounds to achieve the same?

Hi Menos - No… what I do is gray out the image - reduce the contrast - in an image editor.


BackgrountBitmap, no. You have to modify the image itself.

The PictureFrame command attaches an image as a color texture to a surface. You CAN control the transparency of it in Rhino

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Hey Pascal, Yes, that is what I currently do.

I use a background bitmap,

  • start tracing reference features until I know a certain scale or dominant dimensions
  • based on the dimensions I find, I scale the entire trace and scale the background image accordingly
  • continue tracing,
  • add certain dimensions (angles, diameters, distances) in Rhino
  • take a screen grab
  • open the screen grab in, adjust contrast and black point to get a rather pale print I can use as a paper for notes and sketches with pen on paper

@ John - great tip - I will look how the PictureFrame command works - never used it thus far.

I used Background bitmap for the first 6 months with Rhino, then i discovered PictureFrame and i have never used background bitmap since.

  1. Usually I have some dimension or scale I need to work with, I create this first.
  2. I then bring my reference image in with Picture Frame.
  3. I then use Orient 2 points with scale 3d option on. I pick the two reference points in my drawing then the same target points on my lines or guides and this scales my drawing to the size i need.
  4. I then adjust the transparency that i feel comfortable with.


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Hey John and Randy - PictureFrame looks super helpful.
It is much faster to use than BackgroundBitmap as it is a regular object that can be moved, rotated, aligned much faster than the background bitmap.

Somehow I cannot find out though how I can set transparency - any hint on this one or is this a Rhino for Windows only feature?

EDIT: Nevermind :wink: I found it in the material editor (Object Properties / Material / Transparency)
This is so great - I wish I knew about PictureFrame much earlier!

Thanks guys for the fast help!

No , You need object properties panel open, then select the image in your properties panel in the Material select edit. This brings up the Material Editor. Transparency is over on the right.

It’s a bit convoluted , you used to be able to adjust transparency in the properties panel. I still find doing it this way is 2 steps I don’t need.


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