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Simulation Data in Context#

This example composes a steady-state thermal simulation with a detailed NVIDIA GB300 NVL72 server-rack model. The CGNS field data and Universal Scene Description (USD) geometry remain in their native files while OpenUSD presents them in one stage.

GB300 server rack with a thermal volume in the hot-aisle region

The thermal data is inspired by the type of analysis in the NVIDIA Omniverse™ Blueprint for AI Factory Digital Twins. It covers the region near one rack and retains the influence of the surrounding environment.

Note

This example requires the sample data described in Examples. If you have not built Kit-CAE, see Get Started first.

Dataset#

Use the files in:

{path to}/kit_cae_user_guide_data/examples/02_simulation-data-in-context

  • compute_thermal.cgns contains a cell-associated Temperature field on approximately 71,500 nodes and 57,100 hexahedral elements.

  • GB300.usd contains the GB300 NVL72 server-rack geometry.

Import the Data#

  1. Launch Kit-CAE.

    Linux:

    ./repo.sh launch -n omni.cae.kit

    Windows:

    repo.bat launch -n omni.cae.kit

  2. Select File > Open and open GB300.usd. The rack appears in the Viewport.

    GB300 rack visible in the Viewport after opening the USD file

  3. Select File > Import, select compute_thermal.cgns, enable Import to Stage, and select Import.

The imported CGNS hierarchy appears in the Stage panel. Nothing new is visible until you create an operator.

Stage panel containing the GB300 model and imported compute_thermal data

Create a Region of Interest#

  1. Expand the thermal data to Base > Zone > Elements.

  2. Right-click Elements and select Create > CAE Sources > Bounding Box.

    Bounding Box showing the full extent of the thermal dataset

  3. Duplicate the Bounding Box with Ctrl+D.

  4. Press R to scale the duplicate and W to translate it. Fit it around the hot-aisle region directly behind the rack.

    Smaller thermal region of interest from a perspective view
    Thermal region of interest aligned behind the rack from the front

The boxes are standalone USD prims after creation. The full box remains a reference for the simulation extent, and the smaller box becomes the region of interest.

Create the Thermal Volume#

  1. Right-click Elements and select Create > CAE Operators > Volume. Choose nanovdb.

    Volume type dialog with nanovdb and irregular choices

  2. Under Source [Dataset Voxelization], select Add Target for Region-of-interest (ROI) and choose the smaller Bounding Box.

    Volume voxelization properties targeting the smaller Bounding Box as the ROI

  3. Set Max Resolution to 256. Increase it later if the region needs more detail.

  4. Under Colors [Field Selection], use Add Field to select Temperature.

    The thermal field appears around the rack with the default coloring.

    Initial thermal volume overlaid on the GB300 rack

  5. Set the colors Rescale Mode to disable.

  6. Expand Material > Colormap and set the domain to approximately 31 through 37 to focus on the hotter air near the rack. Adjust the transfer function for the desired transparency.

    Thermal volume colormap with a domain of approximately 31 through 37

Toggle the rack visibility to inspect the field alone, then show it again to interpret the thermal result in context.

Adjusted thermal volume showing temperature gradients around the GB300 rack

Note

irregular volume mode preserves supported unstructured cells without voxelization. Use it when cell-level detail is more important than interactive resampling performance.