CAD (STEP) Importer

We provide a STEP (Standard for the Exchange of Product Data) file importer for loading objects that were designed in a CAD software. To enable the STEP file importer if not already enabled, go to Window -> Extensions and check omni.isaac.step_importer.

Import STEP files

Open the STEP Importer on the menu Isaac Utils -> Step Importer, select the desired file and click on Open. the imported asset will appear on screen with a default low resolution. You can get reference sample STEP files on https://www.cax-if.org/cax/cax_stepLib.php

Note

See Mount a Folder to the Container to mount data from the host to a container.

LOD Properties

To improve the import quality of the asset, change the LOD properties on the Step Importer tab. You can have multiple LOD settings, and can select the mesh quality according to the needs.

../_images/isaac_step_lod_0.png ../_images/isaac_step_lod_1.png

Linear Deflection

The linear deflection is a parameter that limits the maximum deviation a tesselation can have from the original surface, it is measured in the triangle normal direction at its center.

Limits the distance between a surface and its tesselation

Angular Deflection

The angular deflection limits the angle measured between subsequent tangents to the surface on the direction of measurement. The angle cannot be greater than the value provided.

Limits the angle between subsequent segments in the polyline

Min Poly Area

The minimum area each triangle on the tesselation can be. This parameter takes precedence over the other configurations and can be used to limit the tesselation convergence.

Use Relative Offset

Scales the Linear deflection by the segment lentgh.

Edit / Reimport Meshes

In this section the user can inspect the properties of each imported mesh, as well as rename the imports. Selecting an item on the list or on stage will select all instances of that item on screen, and double clicking on an item will open that item isolated from the assembly. The control buttons perform the following actions:

  • Show Full Part: Saves changes made to current open asset and reopens the full assembly.

  • Find Similar Meshes: Uses the Metadata (volume, inertia tensor) from the meshes to select all similar meshes on assembly.

    Note

    The meshes selected may not actually be identical, and not all similar meshes may end up being selected.

  • Toggle Visibility: Shows/Hide selected assets.

  • Edit Mesh Names / Done Editing Names: Enters / Exits name editing mode, allowing to change the mesh names.

  • Remove Selected Duplicates: Uses the first selected asset as base and replaces all other selected assets with it.

  • Re-Mesh All / Selected: Re-tesselates All/Selected meshes using the the LOD Properties configured above.

Example of all selected nuts on the imported assembly.

Assembly Description

The assembly Description section shows a tree view of the assembly structure, with sub-assemblies and individual parts. by double-clicking on an assembly, it will save current open asset and open an isolated ivew of the selected assembly.

Assembly tree visualized.

The list also contains an editable list of the materials used. To change the material shader properties, click on the color square to change the base color, or click on the + sign to open the Emissive, Metallic and Roughness properties. Emissive properties controls the color and intensity of light emission by the part. Metallic controls the intensity of metallic reflection, and Roughness controls the smoothness of the reflection surface, where 0 is mirror-like, and 1 is no reflection.

Materials with properties changed and how they look.

The button Edit Assembly Names toggles edit mode, that allows to rename assemblies and materials.

Finish Import

To finish an import click on the Finish Import button, and select the folder where the asset will be saved. All assemblies are stored on the base folder, materials on one usd in the folder materials, and Each solid becomes an individual usd on the folder meshes. If you desire to keep the whole assembly on a single file, check Save Flattened before import, and it will generate a single usd file with the main assembly name on the selected folder.

Folder of imported assets.