topic Re: trapezoid patch corner failure in Fusion Support Forum

trapezoid patch corner failure

kevinwilcox46 — Mon, 27 Sep 2021 10:30:51 GMT

Hi, can anyone explain why this happens, and better still, how to fix it? 'This' being that when I patch a trapezoid (which has a very slight twist, hence patching rather than extruding), it sometimes fails to pick up all four corners. All four lines in this sketch are straight, they are not splines.

Re: trapezoid patch corner failure

piotr.kornafel — Mon, 27 Sep 2021 10:38:57 GMT

Hellow @kevinwilcox46

I would like to ask you to share with us this Fusion 360 design where you observe this odd behavior. I will try to reproduce your issue and report it to our developers.

Below you will find a link to the article:
How to share files in Fusion 360.

Re: trapezoid patch corner failure

kevinwilcox46 — Mon, 27 Sep 2021 11:20:46 GMT

Here you go. It will open at the point where I am aiming to create the next patch.

You'll get a warning that it's using cached geometry, as this is an exported component of a much bigger project and therefore loses it's reference geometry but hopefully it'll still allows you to see what's happening.

The reason I'm extruding from the patches is because using 'ruled' almost always causes filleting of the edges to fail. I had more success with extruding but, as I work along the series of bannisters the twist and curve increases and I have more problems.

Re: trapezoid patch corner failure

kevinwilcox46 — Mon, 27 Sep 2021 11:32:56 GMT

ps. I'm also finding that the 'dropped' corner varies i.e. if I delete the patch and try again, the 'drop' can be on the diagonally opposite corner.

Re: trapezoid patch corner failure

TrippyLighting — Mon, 27 Sep 2021 12:01:21 GMT

A Loft is almost always the better choice to create this geometry.

Re: trapezoid patch corner failure

kevinwilcox46 — Mon, 27 Sep 2021 12:18:15 GMT

Thanks Peter, I think that might be worth a look. It may even reduce the ridiculously large number of steps needed via patching.

Re: trapezoid patch corner failure

kevinwilcox46 — Mon, 27 Sep 2021 19:32:39 GMT

Lofting was indeed a better approach. Although I'm no wiser with respect to the patch issue, I got the job done with far less hassle than would otherwise have been the case.