Overview#
omni.kit.converter.hoops_core converts CAD files to USD using the HOOPS Exchange SDK. This is a core extension without a GUI that provides the fundamental CAD conversion functionality. It can be used directly through its Python API, or accessed through the GUI extension omni.kit.converter.hoops which provides a user interface for the conversion process.
Upon loading, it registers with the CAD Converter service (omni.services.convert.cad) if available, allowing other extensions to utilize its conversion capabilities.
CAD CONVERTER CONFIG FILE INPUTS:#
JSON Converter Settings:#
NOTE: Some converter options have been updated with new keys to replace legacy ones (often in Hungarian notation, e.g. bInstancing). Legacy keys are supported for backward compatibility but will be deprecated. This documentation uses the new keys and provides information about legacy keys in the description of each option.
Format: “setting name” : default value
Converter Option: Instancing#
Description: If true the USD model uses instancing by creating USD References. If false, then there is no instancing at all. The legacy key for this option is bInstancing.
Default Value: true Value Ranges: true, false Data Format: bool
Config File Example:
"instancing" : true
Converter Option: Global Xforms#
Description: When bInstancing is set to false, this flag controls whether globalXforms are composited. If false local transforms are applied. The legacy key for this option is bGlobalXforms.
Default Value: false Value Ranges: true, false Data Format: bool
"globalXforms" : false
Converter Option: Tessellation Level of Detail (LOD)#
Description: Tessellation levels of detail presets provide values to define ChordHeightRatio and AngleToleranceDeg; 0 is the lowest level (ExtraLow) while 4 is the highest level (ExtraHigh). The legacy key for this option is iTessLOD.
Default Value: 2 Value Ranges: [0, 4]
0:
tessLOD0= ExtraLow, ChordHeightRatio=50, AngleToleranceDeg=40,1:
tessLOD1= Low, ChordHeightRatio=600, AngleToleranceDeg=40,2:
tessLOD2= Medium, ChordHeightRatio=2000, AngleToleranceDeg=40,3:
tessLOD3= High, ChordHeightRatio=5000, AngleToleranceDeg=30,4:
tessLOD4= ExtraHigh, ChordHeightRatio=10000, AngleToleranceDeg=20. Data Format: integer
"tessLOD" : 2
Converter Option: Accurate Surface Curvatures#
Description: If true, respect surface curvature to control triangles elongation directions. The legacy key for this option is bAccurateSurfaceCurvatures.
Default Value: true Value Ranges: true, false Data Format: bool
"accurateSurfaceCurvatures" : true
Converter Option: Accurate Tessellation#
Description: If false, tessellate for visualization. If true, tessellate for analysis.
Default Value: false Value Ranges: true, false Data Format: bool
"accurateTessellation": false
Converter Option: Generate UVs#
Description: If true, calls Scene Optimizer Service Kit extension to generate UVs if missing in source data.
See Scene Optimizer Service documentation for details.
Default Value: true Value Ranges: true, false Data Format: bool
Config File Example:
"bOptimize" : true
Converter Option: Dedup Mesh Vertices#
Description: If true, weld mesh elements in appropriate groups. The legacy key for this option is bDedup.
Default Value: true Value Ranges: true, false Data Format: bool
Config File Example:
"dedup" : true
Converter Option: Use Materials#
Description: If true converter creates materials with the color set as an attribute. If false converter will convert colors to USD displayColor primvars. The legacy key for this option is bUseMaterials.
Default Value: true Value Ranges: true, false Data Format: bool
Config File Example:
"useMaterials" : true
Converter Option: Material Select#
Description: If useMaterials is true, sets the material type for target renderer.
Default Value: 1 Value Ranges: [0, 2]
0: No materials
1: USD Preview Surface; default and compatible with Universal renderers
2: OmniPBR + USD Preview Surface; compatible with RTX and Universal renderers Data Format: Integer
Config File Example:
"materialType" : 1
Converter Option: Use Normals#
Description: If true then we pass normals to USD. if false, then we do not. The legacy key for this option is bUseNormals.
Default Value: true Value Ranges: true, false Data Format: bool
Config File Example:
"useNormals" : true
Converter Option: Report Progress#
Description: If true then we report import/export progress. The legacy key for this option is bReportProgress.
Default Value: true Value Ranges: true, false Data Format: bool
Config File Example:
"reportProgress" : true
Converter Option: Report Progress Frequency#
Description: When progress reporting is enabled, this option controls how frequently (in Hz) progress updates are reported during conversion.
Default Value: 4.0 Value Ranges: [1.0, 10.0] Data Format: double
"reportProgressFreq": 4.0
Converter Option: Convert Curves#
Description: If true, convert curve elements into USD Basis Curves; else, ignore these elements. The legacy key for this option is bConvertCurves.
Default Value: false Value Ranges: true, false Data Format: bool
"convertCurves" : false
Converter Option: Convert Metadata#
Description: If true then metadata, including PMI, are imported as USD Attributes; else, metadata are ignored. The legacy key for this option is bConvertMetadata.
Default Value: false Value Ranges: true, false Data Format: bool
"convertMetadata" : false
Converter Option: Override Up-Axis#
Description: Override the up-axis of the converted USD’s stage to Y-up, Z-up, or default to the converter’s up-axis setting.
Default Value: 0 Value Ranges: [0, 2]
0 to default to converter’s up-axis
1 to override to Y-up
2 to override to Z-up Data Format: integer
Config File Example:
"iUpAxis" : 0
Converter Option: Meters Per Unit#
Description: Set the meters per unit converted USD’s stage metric. If set to 0.0, the converted USD will retain the meters per unit from conversion.
Default Value: 1.0 Value Ranges: Positive numbers Data Format: double
Config File Example:
"dMetersPerUnit" : 1.0
Converter Option: Scene Optimizer Config#
Description: (Experimental feature) Provide a path to a saved Scene Optimizer JSON configuration file or a JSON formatted string for executing a predefined optimization process stack.
See Scene Optimizer Service documentation for details.
Default Value: “” Data Format: string
Config File Example:
"sOptimizeConfig" : "converter_config_example.json"
Full converter_config_example.json:#
{
"accurateSurfaceCurvatures": true,
"accurateTessellation": false,
"convertCurves": false,
"convertHidden": false,
"convertMetadata": false,
"dedup": true,
"globalXforms": false,
"instancing": true,
"materialType": 1,
"reportProgress": true,
"reportProgressFreq": 4,
"tessLOD": 2,
"useMaterials": true,
"useNormals": true,
"sOptimizeConfig": "",
"bOptimize": true,
"iUpAxis": 0,
"dMetersPerUnit": 0.0
}
Known Issues#
Please refer to Known Issues for more information.
Licensing Terms of Use and Third-Party Notices#
The omni.kit.converter.hoops_core and related CAD converter Extensions are Omniverse Core Extensions.
Do not redistribute or sublicense without express permission or agreement.
Please read the Omniverse License Agreements and the Third_Party_Notices.md for detailed license information.