I want to create a quick 'groove' in a trimmed surface. Something which is pretty common in ID work and simple to do in Poly modelers. I thought the right approach is Offset Inset with Groove, but alas all my tries have failed. Any help on how best to do this would be greatly appreciated!

Here's the file:
https://altuit.cloud/web/dbpub/3D/groove.3dm

Here's a video describing the issue:

http://www.youtube.com/watch?v=SHtipk_rML4

OK. I figured out one way to do this by Separating the solid and using a VERY SMALL OFFSET.
( see this video: http://www.youtube.com/watch?v=TFPxbec4M2I )

Is there a way to do this with a solid and/or without the very small offset?

Hi Chipp - so in your video when you're asking about the "extra piece" , what I think is happening there is that you were selecting through the hole in the front and getting the face on the back side of the solid to be selected. If you rotated around a bit at that point it would be easier to see that you had the back face selected and not a some duplicate of the front fragment... At least I think that's what's going on in your video there. That's in regard to your first video.

- Michael

Looks like you figured out you were getting the back face selected since now I see in your second video that you're hiding to avoid that happening again.

- Michael

Ok, so right now the Inset command is expecting to have a border area, it isn't possible right now to reduce the border size to 0 like I think you're asking about.

It seems to work ok over here if I leave your pieces all joined, do you have a version with it joined up that won't inset for you?

What you really want here is a way to cut a groove in an object just directly using the 2D profile curve for the cutting. I definitely want to pursue some more stuff related to that in the future but probably it will be initially focused on cutting indentations into a solid using a 2D profile curve where you'll be able to do "depth limited" cuts. Right now you can use 2D curves for doing a boolean but it cuts all the way through the object, not to some limited depth and that's what I would like to add. It would also be good to add some kind of similar groove cutting mechanism where it would be based off of cutting a solid with the profile curve rather than one based on face selections like how the current inset command works. I'm not exactly sure where that would go though, like whether it could go into the boolean commands like a depth limited indentation cut or whether it needs a separate command.

Anyway the current one being based on face selections does not allow for border to go down to zero in width - that would not work work in many other cases like for example if you tried to do a zero border width indentation on one face of a box that would be weird. That's basically why it does not try to do it currently.

- Michael

Thanks again for your help, Michael. Yeah, I went back and did try it with joined surfaces, so I suspect I was doing something wrong in the first video. In fact, I suspect I was SELECTING the back face and had deleted the 'trimmed' face, so the offset was taking place on the back. I'm sorta used to not being able to 'see' surfaces (polys) with normals pointing away, so that probably explains my confusion. Might be something to add in the future (hide back faces).

And FWIW, I think it might just be best in the future to create a cutting object for the groove, that way I think I can get even more detail in my path (not have to worry about radius offsets not working out)