Usage#

The user can then import the DGN file into Omniverse via two workflows: via File Menu Window or via the Content Window.

How to Import and Convert Files#

File -> Import#

  1. To import a CAD file into Omniverse, choose Import in the File menu.

  2. The user should now see a window similar to a file manager. The user needs to then select a DGN file for conversion from this window.

  3. Refer to Converter Options section for more information on conversion settings.

CAD Converter File Import

Import through the Content Window#

  1. By default the Content window is located at the bottom of the Omniverse App. To convert a CAD file to USD, select the file in the Content window and choose Convert to USD in the context menu with right mouse button.

  2. Browse to the location of your file or files, select them, and right-click, and select Convert to USD in the Context menu.

  3. The Converter Options dialog window will appear, modify any options as needed, and click Convert.

CAD Converter Convert to USD

Note: The Content Window tab provides a file browser interface for navigating and managing files. If it is not shown, go to the Menu toolbar, select “Window”, and then select “Content”.

Converter Options#

Convert Options

The DGN converter provides several options to control how files are converted:

Conversion Options#

Option

Description

Convert Visible Only

If enabled, skips hidden elements. If disabled, converts hidden elements but sets them to invisible.

Generate Projection UVs

When UV texture coordinates are missing, uses Scene Optimizer Kit Extension to generate texture coordinates for meshes. Uses default values as described in the Generate Projection UVs documentation.

Enable Instancing

Controls whether instancing is used in the USD output.

Merge Meshes

When enabled, meshes sharing the same level, color, and element type are merged for optimization. When disabled, mesh merging is skipped.

Stage Metrics Options#

These options modify the stage’s metersPerUnit and upAxis settings, applying relevant transformations to maintain proper world space units.

Option

Description

Override Up-Axis

Override the stage’s up-axis to Y-up, Z-up, or use converter default

Meters Per Unit

Set the stage’s meters per unit metric (0.0 retains original conversion value)

Material Options#

Material Type

Description

None

No materials generated

USD Preview Surface

Default option, compatible with Universal renderer contexts

OmniPBR (+ USD Preview Surface)

Compatible with both RTX and Universal renderer contexts

Tessellation Control#

The surface tolerance setting controls mesh accuracy versus performance:

Tolerance Range

Use Case

Result

Low (0.001 - 0.01)

High precision needs

More detailed mesh, larger files, slower processing

High (0.1 - 1.0)

Visualization (recommended)

Less detailed mesh, smaller files, faster processing

Default value is 0.2 for balanced performance and quality. Setting to 0 automatically uses 2.5% of model’s bounding box diagonal.

Note: For detailed information about tessellation, see Open Design Alliance’s blog post

Output Options#

Option

Description

Path

Destination folder for converted USD (defaults to source location)

Scene Optimizer Config

Path to Scene Optimizer JSON config file or JSON string for predefined optimization stack. See Scene Optimizer Service documentation.

Getting Help#