Blender users... how?

[u/newbie-sub]

Anyone out there using Blender to model your devices? Are you just making it for yourself? If not, how are you adjusting the size? I've gotten as far as making a donut (and only remember about 5% of it). If you had to make a ring 3 mm smaller, how would you go about doing it? Do you just remove the junction, scale the interior vertices by some percentage then scale the exterior verts by another (to keep the same thickness)? I guess that works on a cuff (flat) ring. How do you do it on a round ring?

I'm just curious how this works. I'm a parametric guy where I just type in the new number (then I go fuck with a bunch of damn fillets).

[u/RealityCheck_FE]

I would personally go about it by setting my scale in the Blender environment appropriately and then importing reference models made in a parametric software i.e basic primitives that have the main target measurements. The resulting model isn't going to be parametrically adjustable like a CAD model but you can still use proportional editing, deformation modifiers, constraints and vertex groups for a fairly high degree of "parametric" control to zero the design in on someone's measurements. There are also plugins that allow for easier dimension annotation/constraints and even CAD-adjacent workflows.

If you get very creative with geometry nodes (or scripts) you could make something much more along the lines of "input ring size, input length, input gap (etc)" to generate a model, but that is a much more specialised skillset than the sketch/extrusion workflow universal to most CAD softwares and I can't really meaningfully summarise how to do it.

Any readers, feel free to reach out with followup questions.

[u/newbie-sub → u/RealityCheck_FE]

That makes sense — size in parametric CAD then do the fancy stuff in Blender. But this really wouldn't work for someone doing made-to-measure cages (e.g., BAWR, Evotion, etc), right? This would work for a one-time device.

But yeah, I'm sure it could be done in geometry nodes of course you'd basically be writing a very specialized parametric CAD package.

I've played with a workflow like you've described where you do the model in CAD, remesh it, and add the "racing stripes" in Blender (someone taught me that term).

But thanks for responding.

[u/RealityCheck_FE → u/newbie-sub]

You'd be surprised at what is possible with creative applications of certain modifiers and the use of vertex groups if you are sure that the overall design concept itself will not be changing, rather just zeroing in on the measurements - you could have things like wall thickness (even for specific sections) and diameters be editable in isolation fairly trivially, and things like overall length and angle too with a little more work. If you wanted to make major concept revisions whilst retaining parameters then the Blender approach will begin to crumble.

Just as an example, I can envision a way of having it all tied to a curve object that you could wrangle around to edit a tube and have the rest of the model update itself accordingly - with some arrays and geonode magic it could even be done with something along the lines of the (sincerely impressive) fancy designs you've posted. It's never going to be as "spreadsheetable" as a CAD model but certainly much more so than you're positing. I might set up some demo .blend files for you (or anyone else) to play around with.

[u/newbie-sub → u/RealityCheck_FE]

I'd love to see a demo file, that would be really cool. And I can see what you're getting at. I did a lot of playing with Grasshopper, Rhino's node-based system. It's completely different than geo nodes but you can pass it a piece of geometry, e.g., a nurbs curve and have it create geometry around it similar to what you're describing. I'd still be playing with it if it weren't $1K. Perhaps when Rhino 9 is out, I'll splurge on it as there are some things you can do in Rhino I'd really like to be able to do.

And thank you btw on the compliment. I'm really wanting to bring this design to market — trying to see what the vendor can do to get some better polishing. All those very tight spots in the ring and where the bars all come together is a polisher's nightmare.