Fusion360 slow and crashes while merging faces.

[gaston.bougie]

I'm a new user since half a year and have been experimenting with Fusion 360.

Since a few weeks I notice a very slow performance and crashes.

When selecting a face, it takes around 5 seconds to turn blue.

The simplest function of merging 2 faces crashes the application.
The CPU load is around 15%, of which is all related to Fusion's main process (not responding)
The GPU has the latest AMD driver version, and has 2% load.

How can I troubleshoot best, to get to the root cause?

imported stl, converted

[jeff_strater · Accepted solution]

A couple of things, just from your description and the image:

1. This model is from a mesh.  Importing a mesh of this type and converting to BRep is not a great workflow.  You'd be better off using the mesh as a reference and re-modeling the geometry natively, in this case
2. Merge Faces is not intended for merging faces in this kind of a mesh-to-BRep workflow.  It was really meant for usages such as replacing a patch on a complex fillet.  Merge Faces will replace selected faces with a Boundary Patch, which can tend to be very heavy, and imprecise.  No guarantee that you will get planar faces when merging planar faces, and you will never get cylinders, cones, etc.
3. Regarding performance.  If you have been doing lots of Merge Faces so far, that can definitely affect performance, as each one of those adds lots of weight to the model
4. Regarding selection performance:  I'd recommend turning off "Show Default Measure", because, for face selections, this causes Fusion to try to compute the surface area of the selected face:

[gaston.bougie]

Thank you for pointing me in the right direction.
Up until now I could get away with importing .stl's and merge faces.

Sometimes I need a face to get a correct print for extruding, or cutting elsewhere in a design.

I've changed my workflow now, and am able to download/import parts through the gallery.

That is, if they're not available as manufacturer part.

I've also looked deeper into the "default measure" option.

I appreciate your feedback very much.