topic Fusion 360 hangs when adding a line in specific sketch in Fusion Support Forum

Fusion 360 hangs when adding a line in specific sketch

01168997 — Wed, 15 Jun 2022 22:07:01 GMT

Hi everyone,
I've come across a weird bug. I'm working on a sketch in a component and whenever I'm trying to add a line, Fusion 360 freezes and I have to restart it. I tried adding a circle in the same sketch and Fusion had no problem with that. If I add a line in a new sketch in the same component Fusion has no problem either. Has anyone come across problem like that?
It's the first time posting for me here so please tell me if I need to write something more or attach any more information.

Re: Fusion 360 hangs when adding a line in specific sketch

jhackney1972 — Wed, 15 Jun 2022 22:30:01 GMT

It will be a real help to attach your model. If you do not know how to attach your Fusion 360 model follow these easy steps. Open the model in Fusion 360, select the File menu, then Export and save as a F3D or F3Z file to your hard drive. Then use the Attachments section, of a forum post, to attach it.

Re: Fusion 360 hangs when adding a line in specific sketch

01168997 — Wed, 15 Jun 2022 23:21:26 GMT

Okay, it should be attached now. Issue occurs in the only sketch in Component2:1.

Re: Fusion 360 hangs when adding a line in specific sketch

jhackney1972 — Thu, 16 Jun 2022 00:32:56 GMT

I am sorry to say, I see no issue with sketching a line or multiple lines in the sketch you started in Component 2:1. You can see this in the Screencast.

Re: Fusion 360 hangs when adding a line in specific sketch

jeff_strater — Thu, 16 Jun 2022 01:16:50 GMT

I do see the problem. If the lines connect with existing sketch geometry, it will "hang". (I suspect it is not really hung, just REALLY busy, and eventually it would finish). I suspect it would hang with a circle, too, if that circle had constraints to the rest of the sketch. This is something for our sketch team to look at. The problem is all the symmetry constraints. It looks like you have mirrored geometry, and then mirrored the mirror. This is not a complex sketch, so that should be OK, but it clearly is not. If you remove the symmetry constraints, it works fine. So, until this issue is addressed, either:

do your mirroring in the solid world. Any kind of sketch pattern is slow, and mirror seems to be the slowest
achieve your mirror by other means (dimensions, primarily)

[edit] I created bug FUS-106868 for this issue. Thank you for sharing the design with us.

Re: Fusion 360 hangs when adding a line in specific sketch

01168997 — Thu, 16 Jun 2022 11:37:21 GMT

Thank you for your help. Unfortunately even when I try to draw a line that is not constrained to anything in the sketch Fusion still freezes. I don't think it would finish eventually. I tried waiting a few minutes and nothing changed. CPU utilization is also quite low (although there are spikes every few seconds on two cores, but I don't know whether it's Fusion that's causing them). I also checked whether it hangs when I draw a circle constrained to existing parts of a sketch and it does. I guess I'll try reinstalling Fusion.

Re: Fusion 360 hangs when adding a line in specific sketch

paunboli — Thu, 16 Jun 2022 12:56:34 GMT

my pc also hangs sometimes

Re: Fusion 360 hangs when adding a line in specific sketch

jeff_strater — Thu, 16 Jun 2022 21:19:37 GMT

OK, @01168997 you are correct on the hang, I think. I had an extra machine (pretty powerful one), and let it run for 3 hours, and it never finished. So, yeah, I think you are right, it is stuck in an infinite loop, most likely. I will add that info to the bug. "CPU utilization is also quite low". Yes, this is true, but that is likely due at least partly to the fact that the sketch solver is single-threaded, so one CPU might be quite busy, but the rest are idle. Anyway, it is an interesting case, and one that we will definitely look into.

Re: Fusion 360 hangs when adding a line in specific sketch

01168997 — Fri, 17 Jun 2022 08:42:12 GMT

Okay, thank you for looking into this. I also checked on another computer and it didn't freeze when I drew a line not constrained to existings parts of sketch (one machine has AMD CPU other Intel, no idea whether there's correlation).

As a quick fix I copied the sketch onto the same plane in the same spot. It works now if anyone has the same problem but all constraints are gone.