Ahh beautiful and simple solution.

Thank you.

Hi GuyLuke,

When I try boolean union in v5 it works well. All the edges of the red piece disappear. In v4 it works pretty well, but leaves a small malformed edge on the bottom plane that I fixed by deleting that plane, selecting the naked edges, and doing Construct > Planar.

- Peer

Hi GuyLuke,

I'm not sure I understand the result you're looking for.

See attached images (01 and 02 with text)

...or with the very useful "tangentStyler" script from pressure (PEER) :
https://moi3d.com/forum/index.php?webtag=MOI&msg=10937.1

Moi Bueno
MindSet

or maybe this old one...
https://moi3d.com/forum/index.php?webtag=MOI&msg=7912.4

Hi Mindset,

Of course, I'd forgotten about it!
In some cases, I'm not completely satisfied with it for the presentation that I want to achieve and I prefer to deactivate the edges;
I also sometimes create an object that I call 'Hidden' in which I group the edges that I want to hide. But 'tangentStyler' script from pressure (PEER) is a very useful script.