Merging (combine) multiple bodies, computer hangs for 5 minutes

[remiBB5EP]

Hello everyone,

I have a model with few bodies that I need to merge before 3D printing (slicer complains and for some reasons has bad interpretations of surfaces orientation).

Selecting all bodies takes few seconds. OK I can live with that. However, when I click "combine" it takes about 5 minutes to display the popup with the bodies selected. Then another 5 minutes when I click OK.

I am using a MacBook Pro M1. During those minutes, I get the Apple rainbow hanging mouse pointer. CPU sounds not high and fan does not even start. It's like hanging doing almost nothing.

Doing the same operation on a VM with Windows version of Meshmixer (Mac version still not available since security issue) takes about 5 seconds.

Is there something I am missing here? Any other way to quickly merge bodies?

I have attached the f3d so you can see. In the timeline, it's the last operation.

Thank you for any pointer in the right direction.

Torpi

[g-andresen]

Hi,

rightclick design > save as mesh (STL or 3MF) > select option „one file).

günther

[remiBB5EP]

When I do this, slicers like Prusa accept it but other such as Simplify3D complains and see errors like hundred of thousands of non-manifold edges, self-intersections and flipped triangles. The only way is to combine bodies.

[jeff_strater]

You are combining a lot of bodies here.  69 by my count.  That is going to take some time. 

Why does Fusion do it twice?  That is a good question.  The first is for the command "preview", and the second is when you hit OK.  The second time actually does a bit more work, so it is necessary, but this is a valid question.

"Doing the same operation on a VM with Windows version of Meshmixer (Mac version still not available since security issue) takes about 5 seconds."   Mesh combine is not the same operation as BRep combine.  The mesh combine is much simpler, and does not require lots of computation to determine where these fairly complex surfaces intersect.

"During those minutes, I get the Apple rainbow hanging mouse pointer. CPU sounds not high and fan does not even start. It's like hanging doing almost nothing"  Not true.  You almost certainly have a multi-core computer.  During combine, only one of those CPUs is doing any work, because the basic nature of the Combine algorithm is inherently single-threaded.  Which is why the overall performance looks like it is not high - computer performance is represented as a single percentage, which includes what all the other processors are doing, and they are all idle.

The moral is:  Hard things with lots of precise geometry take time.  If you are happy with the output from doing the combine in Meshmixer, then that is a workaround you can use.  If not, then you will just have to live with that 5 minutes for now.

[remiBB5EP]

Thank you for this response, it makes a lot of sense.

My only wish would be that this is done in a background task that does not freeze the UI (so at least I can minimize Fusion and work on something else while I wait). There is no way to cancel the operation. So you don't really know if the operation has crashed or not (the overall progress bar freezes as well). 

Rendering work this way and is perfect. You can cancel it and you know it's working.

P.S. You can do the operation 3 times if you click on "create new component". 

[g-andresen · Accepted solution]

Hi,

I first combined 2 solids and then created the pattern from faces.
The screencast shows the process (about 2'15'') in real time.

günther

[remiBB5EP]

Ho, thanks, that is probably a better way to work it! Thank you @g-andresen 

Still, I think it's scary because it "hangs" / "freeze" and has a lot of UI glitches and hourglass. Would be better to have it decoupled from the UI thread, running in the background, with a way to cancel it or even better, to see the progress !