Weekly Challenge Group

its good one ..thx for that

Nice challenge! 6 features, 10 minutes. I think it would be harder to draw with surfaces.

Can you show your sketches?

I´m a bit confused about creating the radius between the big hole and the outer concave.

Use sweep cut with circle which diameter is equal to the inner diameter of the ring.

That was the breaking point. Thanks a lot.

inventor. A fun one.

This is a deeply fascinating object. If you misinterpret the design intent, you'll end up with something that looks correct, but the large fillets won't work. It is essential to include cuts made with a revolved circle (= boolean subtraction of a torus).

The original Behance post states: 'The Infinite 8 is modeled with intersecting spheres with toruses subtracted'. This is wrong. It should be:

'The Infinite 8 is modeled with intersecting circular discs with toruses subtracted'.

For the heck of it, I designed the Infinite 8 in Designspark Mechanical, which is a FREE CAD software available from https://www.rs-online.com/

This one was a little tough for me, until I saw Strong Dinosaur's hint. Then it was easy!

Finally I got this.

Thank you Jack K.

I have made a parametric model in Solidworks 2014 where you can generate different versions on the fly:

Grabcad model

Parametric Infinite 8

I am fascinated by the model in this challenge: https://grabcad.com/groups/weekly-challenge-group/discussions/challenge-infinite-8 so I did a parametric Solidworks 2014 model. Use Tools -> Equations to show the Global Variables and change these to generate new versions of the model on the fly.

Nice work. I did this challenge on reddit and thought parametric would be fun but never materialized it. :D

Thank you :-)

This one is tougher than it first appeared to me.

What technique are you guys using to get the surfaces in the circle #1 to flow together? That is not filet. The surfaces seem to be tangent with no harsh corners.

Also, is surface 2 angled? It appears to be to me in the drawing from the original challenge posted.

I can get here with a few revolves, but I really don't think I am on the right track to make the surfaces like on the yellow one pictured above.

The hole is too small relative to the thickness of the disks. This produces a knife edge on the edge of the disk that probably makes it impossible to resolve the fillet.

It isn’t just a couple of revolves. It is two flat disks at 90 degrees to each other with no holes in the disks. Then a separate revolve that simultaneously cuts the hole in one disk and cuts the radius in the edge of the other disk. Do this twice. The revolved cut uses a circle sketch that must be larger than the thickness of the disks. The resulting hole in each disk is not a straight hole. It is a section of a torus.

To answer your original question, yes that is a simple fillet. If the two disks are cut properly by the two revolutions, then it all blends perfectly together.

Thanks. I will try adjusting those sizes

Another thing to consider. For the fillet to work, the hole diameter must be at least as big as the disk thickness plus twice the fillet radius. Start with a hole diameter about twice the disk thickness.

The way you have it with the hole diameter about equal to the disk thickness leaves zero room for the fillet.

on AutoCAD

done

how about this?

@steenwinther @bobwiley

It took a few attempts, but the final result is satisfying