Proposal: "Chamfillet" / Printable bottom edge treatment for 3D printing

[corefile]

I've been using "Chamfillet" for years on the bottom edges of my designs, adding a standard fillet to bottom edges touching the build plate causes steep horizontal overhangs (0°) that droop and print poorly without supports. A standard 45° chamfer solves printability and elephant's foot, but leaves a sharp, harsh transition ridge. That is where a Chamfillet comes in:

The Chamfillet Solution blends the best of both worlds:

• At the bed: Starts with a flat 45° (or ≤ 45°) chamfer directly off the plate so every layer is 100% self-supporting without supports.
• Transitioning up: Tangentially sweeps into a rounded fillet radius that blends smoothly into the vertical wall.
• The result: An edge that prints cleanly with zero drooping, resists elephant's foot, and feels soft and molded in your hand.

OnShape, for example, has a FeatureScript named Chamfillet

Given Layerling's focus on easy CAD for 3D printing, would you be open to adding Chamfillet support? We could either introduce it as a dedicated edge modifier kind or as a compound chamfer+blend workflow with a "Bottom edges" selection helper.

What would be your preferred UX and approach for this?

[prmod3d]

I like this idea! I also manually create chamfillets occasionally, and having it as an option would be a big time-saver. Plus, I suspect more people would use it if the option existed, while also learning about why and how it results in better quality printed models. It's the same as the teardrop holes (which layerling already offers), that a lot of people aren't aware of at first and then are really happy to have an easy way to use them once they understand the purpose.

[RobbieKnobbie]

Let me get this straight, you're chamfering a bottom edge, then applying a fillet to the transition from the fillet to the vertical face.

That's two steps, right? I don't think I understand.

[prmod3d]

Yes, two steps. I'm presuming you're implying that's not worth creating an option for?

The problem is you don't currently get to see how the two tools (chamfer and fillet) interact with each other to achieve a desired result. You set the chamfer, then the fillet, and then go back to edit the chamfer, which affects the fillet in a way that you have to then edit it as well. Two steps can easily turn into 10 steps or more, and you end up just saying it's good enough because it's too difficult to make precise.

A dedicated chamfillet option would (presumably) allow for a visually intuitive blend of the two features -- with different length and radius between the transitions that you could see and adjust before applying the action.

[RobbieKnobbie]

Yeah, I'm definitely not seeing it.

to my mind, you add your chamfer, adjust to meet your requirements, then round the edge, and move on. I guess I'm not understanding the 'going back' part maybe; I'm going to guess your workflow is different to mine? When I apply an edge treatment, I see in my mind pretty much what I'm going to get, unless I'm rounding a lot of complex curves or skew planes etc, but that's fairly rare (at least for the goofy stuff I do) and there's seldom much adjustment.

Anyway, and I expect you're going to assume I'm implying again here, but if you were looking for precision, then you'd be using a mechanical modeler like freeCAD or Fusion, rather than an entry-level package like this.

Again, I think I'm not seeing it, but hey, different strokes! Have a good rest of your weekend.

[corefile]

not exactly - what I think you are describing is just a regular full chamfer and then rounding off the top edge. That is not what a chamfillet is. Think of it more of a chamfer but about halfway up it transitions to a fillet (which is not the same as just rounding the top end of a chamfer) its a really nice effect. You can search youtube for chamfillet and there are a couple videos that illustrate it much better them my description. I'm working on the PR now

[prmod3d]

Thanks for the clarification @corefile. It's now obvious to me that without access to the proper tool I was just Tinker-hacking chamfillets!

[henmedia]

@corefile, @prmod3d the Chamfillet is out in 1.89.0: the Chamfer window has a choice at the top, Chamfer or Chamfillet, a chamfer at the plate that blends tangentially into a fillet toward the wall. With Bottom edges it takes the whole foot of a part in one click, and it is built in the CAD kernel, so the STEP export keeps it exact. Thank you corefile for building it. Reload the page to get it; the installed app needs a restart.

[corefile]

Doing some QA - but looks good - should it have its own modify button, or a toggle in the chamfer or fillet menu ? In this version it does not have a dedicated modify button, if you toggle it on the menu becomes a chamfillet menu (for just that one time)

[RobbieKnobbie]

Alright, the horse is dispatched, but I'm still kicking... I'm still trying to figure out the difference between the chamfillet you show in the screenshot above and a chamfer plus a (more or less) equal radius fillet.

This is a quickie attempt to mirror what you posted there...

I may have the proportions slightly off, but I seriously can't see the difference.

Forgive my naivety, be can you explain it to me like I'm a five year old?

[henmedia]

@RobbieKnobbie your picture is a fair test, and the shape is close to what the Chamfillet gives. A chamfer plus a fillet on the edge where the chamfer meets the wall is the same idea. What the tool adds is that the blend is tangent, so there is no ridge, and that the proportions are chosen for printing: a short 45° chamfer at the plate, so the first layers need no support, and the rest of the height curved. It makes that in one step, and with Bottom edges for the whole foot of a part at once. If your two steps already give you the shape you want, you lose nothing by keeping to them.

[corefile]

Actually a dedicated modify button seems like a better option - and I fixed the geometry of the chamfillet now its a proper chamfillet

[henmedia]

Thank you for the proposal and for the pictures, a bottom edge that prints without support and still ends soft is a good fit for what layerling is for, and the "Bottom edges" button that came in 1.87.0 is a good partner for it. Thanks also to everyone who joined the discussion.

On your question: I'd rather not add another button to the toolbar, as the bar is already tight in narrow windows. A third kind inside the Chamfer tool (next to the straight chamfer) would be my preference, but let me see your pull request first. When it is ready, please also make the edge exact in the CAD kernel like the other edge treatments, and add a test; I'll take care of the guide and the AI connection afterwards.