Imported STEP file USD losing reference path in XForm subtree after saving to different location

Omniverse Isaac Sim
1

Hello,
This bug appears when importing STEP file, finishing import to some location and then “Save as” as another usd, top tree components have path correction, but subtree no.

Selection_119
Selection_119407×567 156 KB
Selection_120
Selection_120407×567 142 KB

Version of isaac-sim-headless is 2020.2.28133

2

would you be able to provide a step by step reproduction of what you are experiencing?

One thing to consider is that the reference paths are based on their parent’s path, so for example if your dependency tree looks something like this:

-a/b/c.usd
  -../d/e.usd
   -f.usd

the search paths for each item will be:

a/b/c.usd
a/d/e.usd
a/d/f.usd

You can use the USD Paths (Window->USD Paths) Extension to verify the search paths.

In the reference step file example from the documentation, notice how the reference to the materials asset used by the meshes USDs contains an elipse back to the parent folder:
image

You can also use the USD paths extension to mass update the reference paths if you move the usd assets after exporting.

3

Sure, here’s the steps:

  1. Take step file with complex tree structure, like You can see in my example ( i.e. Main usd consist of many small usds, which are combined to represent some bigger component ). I think any STEP file exported from Inventor with enough details will suite.
  2. Import it through step importer from Window->Isaac->Step Importer.
  3. Finish import to some folder
  4. After window refresh → “Save as” to same folder you have picked to save import ( Not one created after “Finish import” process )

This steps should produce result above.

4

Thank you. I can reproduce what you are seeing.

This is indeed expected behavior, as mentioned above, the reference paths are always with respect to the direct parent of the assets, therefore a sub-item reference will be resolved according to the parent’s path. your item will still load correctly.

I recognize, however that this makes the path unclear from the details pane, and breaks the “Show in content” shortcut button. The next release has reworked the Details UI and we will make sure to take notes on the references pane and ask for a UI that is more intuitive.