How to make precise filets (grooves) on non-equilateral shapes?

The title says it all. Is there a mathematically precise way to make filets (grooves) on complex shapes in Blender? In other words, how do I make a groove around a window that has 12 edges that are not equilateral? The groove created for the filet must have the same width no matter where it’s measured…

For those who don’t understand what I’m talking about, I’ve included a very simple example below. I’ve got a sneaky feeling someone is going to remind me that Blender is not a CAD program, but that’s OK. :wink:


I think Bevel Center script in Mesh Scripts may be what you’re looking for.


Blender is not CAD true but it does have a grid, loop cut, extrude and so on
and with grab you should be able to make what you want.
We will need to see exactly what your modeling I think.

There are a lot of tools in blender that allow you to model things to a precise size, Most are covered in theEngineers Guide and tutorials.

Thanks for your answer, Syziph. I hadn’t played with that script yet. However, it doesn’t seem to produce a result that is mathematically precise with complex shapes. If you consider the test below, you can tell that the bevel created isn’t the same width all around. Nevertheless, it’s still an interesting tool though…


Thanks for your answers, guys.

@JDA: I need to make a filet around car window. If you look at the example above, it will give you an idea of what I’m looking to do. Up to now I have used grab and reference points using other edges that I placed at right-angles respectively to each edge of the bevelled groove. It works, but it’s… rather tedious (and that’s an understatement).

@robbur: Thanks for the tip. The tut looks great. I’m definitely going to dig into it tomorrow (it’s getting a bit latish now).

It sounds like you’re needing the “inset” function found in other apps. Blender doesn’t have it built-in yet. Macouno wrote this script which is not perfect, but comes close.

Thanks CD38, great tip. I’ve tested the script a bit, and yes it’s what I was looking for, so you’ve solved my problem. :slight_smile:

JohnV1960, I am glad you’ve found sollution to your problem!

However, as robbur said - Blender is fully capable of creating models with precision. I strongly recomend you to visit his website and go through the tutorials there.

This is what I made based on your second image and using Snap tool, Normal Orientation and Geom script for cutting the edges at desired locations.


Thanks Syizph. I’ve been digging into robbur’s tut and I must say it’s a goldmine of information. For my current project, I don’t think I need that much precision so I’ve decided to go with the inset because it uses less verts. But in the future I want to make the inner workings of a watch and I’ll need the pieces to be extremely precise, so I’ll definitely be using robbur’s tut a great deal.

Thanks for taking the time to show me how to make the bevel center script work properly. I wasn’t aware of the geom tools and there are some interesting utilities in there. I’ll be looking into those too…

Thanks for the comments on my tutorials. Hope you find them useful. I am currently half way through my next one, which is how to build a casting around an assembly of components. It might help with your watch project.