I can't Boolean Diff these two solids. I suspect it's because of the cross-over nature of the heart sweep. The black rail used for the sweep is a continuous curve.

Can anyone recommend a way to accomplish this design?

Will it Boolean Diff in Rhino or some other program?



I'm out of forum space to post a 3dm file, but happy to email. I think any swept "pretzel" shape will have the same issue.

Ed Ferguson

Email the file to me at burrmanator at gmail dot com

Also, with your permission here, i'll post the file, so you can get input from others too.

You right only one volume overlapped don't works even Unioned or Merged but...
Ok I found the trick! :)

Trim first the curve itself
Sweep each part of this curve in one time! (on the video it's one by one ...no need ;)
Union all parts
Kill the curves
Make the Boolean Diff! ;)
Et voilà! Joyeux Noël! :)

Pilou - Merci mon ami

Performing the Mutual Trim on my hearts curve and Sweeping each segment as you suggested got me moving forward. From there I Flowed the segments onto my ring and Boolean Diff to complete my ring model.

BurrMan - Thank you for the offer to help. I emailed the 3dm if you want to experiment. As you know, with MoI there are often multiple solutions.

Ed Ferguson

Awesome result Ed, and Frenchy touched on where I was going.

Basically, break it up into sections that can array to make your chain. As long as it is uniform... which is how I did this model.
The half solids booleaned together, then could boolean out of your block.

In case it's not though, I wanted to add one more part.

I swept only a half circle. This would allow me to remove the top surface of the half sweep, trim out the inner, unwanted walls (Separate and trim parts with parts), then I could have the half shell, essentially what a boolean diff would produce. Then I just have to build the boundry surface, with some type of shape and planar...

Then you could flow.

Anyway, thats one added point to Frenchy's point...




Ed's original file is Heart Boolean Diff.....

Thanks BurrMan - Good input!

Ed Ferguson

Hi ed, please try attached technique. Let me know if you're still stuck.

(started earlier and finished up, late to the party!)

- Michael

@ Michael Why trim the middle little part?
Seems that works without it! If each curve has no overlap itself... :)



@ Burr thx! :)

@ Ed : nice one!

Hi Pilou, I didn't trim there, that was a blend curve I put in since I sketched the pretzel instead of making it out of control points with alignment.

- Michael

Ok because that was writed "break" at these points! :)

Hi Pilou,

re:
> Ok because that was writed "break" at these points! :)

Yes, with the original description of it being one long unbroken curve, that case would need a break in that spot.

- Michael

Thanks Michael -

Yes, that does work and I remade my model as below.

I first performed a Mutual Trim on my curve, took a short section shown in green, Mirrored it, Copied, and Joined to make the longer green & red chain. Then I performed a Sweep on each colored section and Boolean Union into a solid. Then I Flowed the design around the ring and Boolean Diff.

I made no attempt to match up the ends, as they are on the bottom of the ring, and this model is for rendering, not mfg. When I make the ring on a rotary table on the milling machine, the ball-nose cutter follows long continuous curves to produce the grooves. These curves match up on the ends for a seamless design.

Thanks again Michael, BurrMan & Pilou. I'll be making similar designs in the future and now I have a process for making the models.

Ed Ferguson

that's an awesome design. someone is going to be a very happy ring owner.