topic Re: Circular Twisted Torus - Is this shape possible? in Fusion Design, Validate & Document Forum

Circular Twisted Torus - Is this shape possible?

bradandersonjr — Sun, 12 Mar 2017 21:38:40 GMT

Hey everyone!

I've been working on a quick, little project (of course!) and while I've mostly achieved my goal I was wondering if I am able to push it further. The objective is a twisted 4-sized torus. I've been able to create the basic shape but my question is am I able to force it to have a perfectly circular profile? Here's an example of what I'm talking about.

The blue lines represent the circular profile I'd like to achieve, while the purple lines are the actual splines used to achieve the twist.

I drew the splines then lofted them one at a time in Patch mode, then stitched them together.

Here's a reference of my goal.

Thanks!

- Brad

Re: Circular Twisted Torus - Is this shape possible?

Anonymous — Mon, 13 Mar 2017 00:24:07 GMT

It looks like a simple loft with circular centerline. You need several construction planes along that circular path. Then first profile is a rectangle with side length, let's say, 10. Second profile is 45 degrees rotated rectangle with diagonal 10. Next profile if the same as the first. And so on. When loft - adjust its guidelines so the body twist.

Re: Circular Twisted Torus - Is this shape possible?

Anonymous — Mon, 13 Mar 2017 00:24:31 GMT

And just simple loft between 4 squares with 4 corners rails looks almost perfect.

Re: Circular Twisted Torus - Is this shape possible?

mroek — Mon, 13 Mar 2017 08:39:41 GMT

@Anonymous

Great solution, and as a learning exercise I tried to replicate what you did. However, getting the guide rails constrained to the corners of the sketch rectangles had me confused. First I tried just drawing a guide rail on a plane, then explicitly moving the guide rail with the move tool to force it to become a 3D sketch. After that I thought I'd be able to edit the sketch and apply the constraints, but that seems to not be possible.

Eventually I discovered that I had to snap to the corner points when initially creating the sketch. Is there really no way to apply constraints in 3D after a sketch has been created?

Re: Circular Twisted Torus - Is this shape possible?

Anonymous — Mon, 13 Mar 2017 10:59:25 GMT

You can apply constraints after.

2 necessary steps to do that:

1) Make your spline 3D first (by moving it from sketch plain using Move command.

2) Make 3D projection of the point to snap to the sketch where your spline is. Use "Project -> Include 3d geometry" for that.

After that you can make that point coincident to point of 3d spline.

Fusion loves to do auto-projection for you, so it does (2) when you snap spline initially while drawing.

Re: Circular Twisted Torus - Is this shape possible?

mroek — Mon, 13 Mar 2017 11:05:48 GMT

@Anonymous

Thanks. I actually discovered that myself, just before you posted the reply. It isn't all that intuitive, but when you know about it, it is at least workable.

Re: Circular Twisted Torus - Is this shape possible?

bradandersonjr — Fri, 17 Mar 2017 14:25:05 GMT

Thanks GrAndAG!

It appears your second solution is the same approach as my original attempt, just with the square profiles oriented correctly. I had mine at a 45 deg. rotation which would explain my silhouette being more narrow than yours. I figured it'd be a simple solution that was hiding in plain sight.

Thanks again!