Reducing 3D component / step file complexity

[joe.burks]

Is there a way to reduce the poly count or otherwise improve the performance of a mechanical design using a 3D PCB?

I've received feedback from my colleague who does the mechanical design that my 3D PCB causes a significant performance hit when he imports my 3D PCB. I think this is because of the high poly count / complexity of the 3D component models on the board. I'm wondering if there is an option that can reduce the overhead without going all the way down to a block with 6 faces.

E.g. this gorgeous rendering which apparently has too much detail and causes the workstation doing the mechanical design to chug much more slowly:

[matt.berggren]

A few comments on this which I hope help with the issue your ME is experiencing.  Firstly though, let me ask if you are using STEP because the engineer is using a tool other than Fusion?  If this is the Fusion native model, there is a lot you can do but that is a good thing to know up front.

Assuming you are both using Fusion, the approach I would suggest is to try a few things:

1)  Reduce the amount of geometry you are sending to them by unchecking the option to include Soldermask or Copper in the 3D PCB (for now).  You can always add this back later but it very likely doesn't help them with their work.

2). The next thing I would do is perhaps be a bit more selective about the components you send them.  If they aren't critical to mechanical design (eg connectors), uncheck them in the list of components when you send the board.  Some times we (me included) feel that all of the detail is the only valid version of the design and we want that amazing render, but truly, the ME is likely to grow frustrated with any 3D PCB (especially one in STEP format!) if they load that much detail into the tool they use.

3). If they still want to see performance pick up, then I would actually suggest they disable parts of the PCB in the Browser in MCAD.  If the items aren't visible then the hit test doesn't have to deal with them, the rendering doesn't have to deal with them, and then the highlighting of them doesn't need to occur back in the Browser tree.  If you consider the overhead of each of these, they can add up, depending on the complexity of the board.  The one's I would look at are specific components that may have come in faceted (some sites you download from might use mesh models which create a lot of overhead), solder mask, copper and usually I can find one or two offending objects that were simply created with a brilliant level of detail but not really considering performance.  

We see this especially with text that is printed on the top of models and any text etched into the body of a part (eg. those nice looking TI logos are great and all, but the more text you include, the harder this is for any modeler to contend with).

Hope this helps!

Best regards,

Matt

[matt.berggren]

Sorry, I should add that the models we create with our Package Generator and the PCB are all Surface Solids.  They are not faceted mesh.  There is no polygon faceting and though the first reaction is generally:  'how can surface solids be fast?' the reality is that by controlling the nodes in the tree and bundling things under a few high level nodes you can turn on / off, ensures we have FAR more information for things like selection, snap, Project to Plane, move to point, etc.  This is the key benefit that we did which is completely unique to the Fusion implementation. We are constantly working to provide the tools to keep the speed up, but there is a lot of information we would be throwing away that the ME will invariably want, if those things were managed properly (ie in proper, mechanical / timeline-oriented solid geometry).  So the short answer to the polygons is you can't just dial down the drawing from a mesh standpoint but there are options for detail and in-canvas rendering in the Preferences (see below).  I would stress however, that just dialing back the rendering will not necessarily improve performance because the rendering is only one component of the editing experience.  See below for the in-canvas performance options.

Best regards,

Matt - Autodesk

[joe.burks]

I'm using STEP files because nearly all manufacturers I source components from provide their 3D models as STEP files. I'm concerned to see your comments on Fusion 360 and STEP files since I believed this would not be a problem for Fusion 360 since Autodesk has published a video on exactly this workflow: https://www.youtube.com/watch?v=w7GFaCYed30. Is there some other workflow this video should have directed me to?

Both my colleague and I are working in Fusion 360. As shown in the image I provided, I had stripped nearly everything off the board except the ports that were needed to fit the board on the mechanical part.

[joe.burks · Accepted solution]

I traced the bulk of the issue down to the 12401832E402A USB-C connector from the "Fusion Electronics" folder on Library.io. That component has 75 bodies:

Only about 4 are necessary to get an accurate 3D model of the part:

Creating a new component with only those parts significantly sped things up. I have no idea what mechanical 3D format library.io uses nor the specifics of the "Fusion Electronics" folder. They seemed to be available by default so I had assumed that they were safe.