More trouble with decals

I was looking through some search results on decals and couldn’t find a specific solution or better yet a best practices for how to do this… your help is greatly appreciated.


In my simple model, I have 2 pcs of black plastic where 1 face will be printed with either a full graphic, or a line of text.


My thinking on how to accomplish this was to:

  1. assign the poly surface(s) that describes the part as black plastic material
  2. Assign a decal to the face that would receive the printing.

When attempting this, I notice that sometimes the process work and other times it does not. A file that works once, may not work correctly later. I cannot tell if this is something I am doing or not.

See the following images and 3dm file:

1 Screen Shot RENDERED.png - (shows what I am trying to get)

2 Screen Shot RAYTRACED.png - (shows a preview of the rendering in progress - no decals)

3 materials and details properties back panel.png - (shows properties…)

4 materials and details properties lower panel.png - (shows properties…)

5 Rendering preview.png - (shows a preview of the rendering in progress - no decals)

Bitters counter display.png - (an early version where the decals actually worked)

Bitters case display.3dm - (file in question)
Bitters case display.3dm (5.8 MB)

Q- is there something I am doing wrong? What am I missing?
Q- is there a better mapping approach?
Q- am I asking too much from this particular cpu/setup?

Rhino Version 7 (7.19.22180.09002, 2022-06-29) [Mac]
Evaluation copy (no plugins added, no updates)

Mac OS Monterey 12.5
MacBook Air (Retina, 13-inch, 2019)
1.6 GHz Dual Core Intel i5
Intel UHD graphics 617 1536 MB

thanks again! -jc

Hi John - check the projection direction of the decal - (forward, backward, both).


Hi Pascal,
I appreciate the suggestion.
It looks like I am projecting in the right direction (I tried backwards and both and back to forward to see if it would change, but to no avail)

the widget is extremely helpful (kudos to mcneel on this).

thanks for the suggestion Pascal!

Hi jc - maybe I am being dense about what question you are asking - what you show there looks correct, right? Not black?


lol, no you are not dense… the rendered view is good, its the raytrace view shows all black.

I Was being dense - -ok- checking. Yep, OK, I get the raytrace black on Mac, OK on Windows.


no worries!
I was experimenting with UV mapping vs decal and it seems to be no issue as a UV map.

would the software possibly drop out the decal due to memory issues? I’m using an older MacBook Air
just trying to learn how to best use resources!

Hi John - I have a newish M1 mac and it does not look correct here either.
I can add your image as a decal in a new file and it works and I can bring that object into your file and it works… still digging.