USDZ File Exported from Fusion 360 Cannot Be Loaded in Isaac Sim

Isaac Sim Version

4.5.0
4.2.0
4.1.0
4.0.0
4.5.0
2023.1.1
2023.1.0-hotfix.1
Other (please specify):

Operating System

Ubuntu 22.04
Ubuntu 20.04
Windows 11
Windows 10
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GPU Information

  • Model:
  • Driver Version:

Topic Description

Hi everyone,

I tried to export my robot model from Fusion 360 as a USDZ file and import it into Isaac Sim, but I encountered the following error. About six months ago, this method worked without any issues.
What could be causing this error? I am currently in contact with Fusion 360 support for assistance.

Thank you!

Error Messages

2025-02-20 05:56:15  [Error] [omni.usd] Runtime Error (secondary thread): in _ReadSpecs at line 3527 of /builds/omniverse/usd-ci/USD/pxr/usd/usd/crateFile.cpp -- Corrupt asset @/home/robot/hisamichi/3Dcad/rollopod_b_simplification_rolling_v20.usdz[rollopod_b_simplification_rolling_v20.usdc]@ - ignoring invalid specs: spec </.extent> repeated, spec </.normals> repeated, spec </.points> repeated, spec </.subdivisionScheme> repeated, spec </.verticalAperture> repeated, spec </.xformOp:transform> repeated, spec </.xformOpOrder> repeated, spec </> repeated, spec at index 2 has empty path, spec at index 4 has empty path, spec at index 6 has empty path, spec at index 8 has empty path, spec at index 10 has empty path, spec at index 12 has empty path, spec at index 14 has empty path, spec at index 16 has empty path, spec at index 18 has empty path, spec at index 20 has empty path, spec at index 22 has empty path, spec at index 29 has empty path, spec at index 31 has empty path, spec at index 33 has empty path, spec at index 35 has empty path, spec at index 37 has empty path, spec at index 39 has empty path, spec at index 41 has empty path, spec at index 43 has empty path, spec at index 45 has empty path, spec at index 47 has empty path, spec at index 49 has empty path, spec at index 51 has empty path, spec at index 53 has empty path, spec at index 55 has empty path, spec at index 57 has empty path, spec at index 59 has empty path, spec at index 61 has empty path, spec at index 63 has empty path, spec at index 65 has empty path, spec at index 67 has empty path, spec at index 69 has empty path, spec at index 71 has empty path, spec at index 73 has empty path, spec at index 75 has empty path, spec at index 77 has empty path, spec at index 79 has empty path, spec at index 81 has empty path, spec at index 83 has empty path, spec at index 85 has empty path, spec at index 87 has empty path, spec at index 89 has empty path, spec at index 90 has empty path, spec at index 91 has empty path, spec at index 92 has empty path, spec at index 93 has empty path, spec at index 105 has empty path, spec at index 116 has empty path, spec at index 117 has empty path, spec at index 118 has empty path, spec at index 119 has empty path, spec at index 120 has empty path, spec at index 121 has empty path, spec at index 122 has empty path, spec at index 123 has empty path, spec at index 124 has empty path, spec at index 125 has empty path, spec at index 126 has empty path, spec at index 127 has empty path, spec at index 128 has empty path, spec at index 129 has empty path, spec at index 130 has empty path, spec at index 131 has empty path, spec at index 132 has empty path, spec at index 133 has empty path, spec at index 134 has empty path, spec at index 135 has empty path, spec at index 136 has empty path, spec at index 137 has empty path, spec at index 142 has empty path, spec at index 143 has empty path, spec at index 144 has empty path, spec at index 145 has empty path, spec at index 203 has empty path, spec at index 214 has empty path, spec at index 215 has empty path, spec at index 216 has empty path, spec at index 217 has empty path, spec at index 218 has empty path, spec at index 219 has empty path, spec at index 220 has empty path, spec at index 221 has empty path, spec at index 222 has empty path, spec at index 223 has empty path, spec at index 224 has empty path, spec at index 229 has empty path, spec at index 240 has empty path, spec at index 241 has empty path, spec at index 242 has empty path, spec at index 243 has empty path, spec at index 244 has empty path, spec at index 245 has empty path, spec at index 246 has empty path, spec at index 247 has empty path, spec at index 248 has empty path, spec at index 249 has empty path, spec at index 250 has empty path, spec at index 251 has empty path, spec at index 252 has empty path, spec at index 253 has empty path, spec at index 254 has empty path, spec at index 255 has empty path, spec at index 267 has empty path, spec at index 270 has empty path, spec at index 271 has empty path, spec at index 272 has empty path, spec at index 273 has empty path, spec at index 274 has empty path, spec at index 275 has empty path, spec at index 276 has empty path, spec at index 277 has empty path, spec at index 278 has empty path, spec at index 279 has empty path, spec at index 280 has empty path, spec at index 311 has empty path, spec at index 314 has empty path, spec at index 315 has empty path.
2025-02-20 05:56:15  [Error] [omni.usd] 
2025-02-20 05:56:15  [Error] [omni.usd] Failed to open : /home/robot/hisamichi/3Dcad/rollopod_b_simplification_rolling_v20.usdz
2025-02-20 05:56:15  [Error] [omni.kit.window.file.file_window] Failed to open stage /home/robot/hisamichi/3Dcad/rollopod_b_simplification_rolling_v20.usdz: Failed to open:/home/robot/hisamichi/3Dcad/rollopod_b_simplification_rolling_v20.usdz

Hi All,

I have tried various things since then.
I checked using OpenUSD and found that non-English characters were used in object names, so I fixed them. I also flattened it using the usdview tool.
However, I still cannot import the original robot’s USD in Isaac Sim. I share the new error code.
Does anyone know what kind of issue we are facing?
Thanks!

Errer code:

2025-03-13 04:07:55 [Error] [omni.usd] Failed to open : /home/robot/hisamichi/3Dcad/rollopod_b_simplification_rolling_v25_flattened.usd
2025-03-13 04:07:55 [Error] [omni.kit.window.file.file_window] Failed to open stage /home/robot/hisamichi/3Dcad/rollopod_b_simplification_rolling_v25_flattened.usd: Failed to open:/home/robot/hisamichi/3Dcad/rollopod_b_simplification_rolling_v25_flattened.usd

hi @Hisamichi , the error log provided is quite limited. If direct USD export seems to be an issue, maybe try using the CAD importer to get the robot/assets into Isaac Sim?

Hi @rchadha,

Thanks for the advice!
I was able to import USDZ by flattening it with OpenUSD’s usdview and converting it to .usda with usdcat.
I will also try the method you suggested me.