topic Re: Better way to offset in Fusion Design, Validate & Document Forum

Better way to offset

smallfavor — Mon, 26 Dec 2016 23:29:34 GMT

I want a evenly offset curve to complete a profile for a bowl. The curve to be offset is a spline and creating a regular offset causes problems when I need to edit - despite deleting constraints. Here's two vids showing the problems. What is the best and least time-consuming way to get this done?

http://autode.sk/2hIp64j

Re: Better way to offset

jeff_strater — Tue, 27 Dec 2016 00:37:49 GMT

The offset of a spline is not a "regular" spline in Fusion. You can tell this by the fact that there are no fit points on it, and no tangent handles when you select it. Even if you break the offset, it is still not a regular spline. So, when you drag it, all you can do is translate the whole curve.

What I would do in this case is to either draw the offset manually using a separate spline command, either by eye, or by tracing the offset with a new spline. Or, leave the offset as an offset, and add other curves to join where needed.

If you can share the model, I can play around with it, and show you how I would do this.

Jeff

Re: Better way to offset

smallfavor — Tue, 27 Dec 2016 00:59:26 GMT

I've attached the model to another recent post that's in the same state as when the vid was made.

I'm pretty sure this is it.

The second one is what I managed by making a copy of the first spline and using some additional lines as you suggested.

It would be very cool if parallel worked on curving lines as well as the straight ones.

Re: Better way to offset

jeff_strater — Tue, 27 Dec 2016 01:44:31 GMT

Your example with the extra lines is exactly what I was thinking.

Here is a screencast that shows another approach. Leave the offset as an offset, make it a construction curve, then fit a spline to it such that the fit points are constrained to the offset, but extend it further so that it meets up with the other curve. Then, you can still edit the offset and the new spline will update along with it:

Jeff

Re: Better way to offset

smallfavor — Tue, 27 Dec 2016 17:04:19 GMT

I see you used more control points than I. I'm trying to keep it all as simple as possible but maybe I overdoing it. Any general approach to splines aside from keeping them asap?

Re: Better way to offset

Beyondforce — Tue, 27 Dec 2016 17:26:27 GMT

Hi @smallfavor,

I'm assuming you want to create an offset to control the thickness and shape of the bowl. Maybe this will help:

Cheers / Ben
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Re: Better way to offset

smallfavor — Tue, 27 Dec 2016 17:59:58 GMT

That was nice! It's like going back to Rhino. Thanks.

Re: Better way to offset

Beyondforce — Tue, 27 Dec 2016 18:07:37 GMT

Fusion 360 is packed with great tools, but in the end, it's all about the techniques!

I'm glad I could help.

Ben.