VTK to USD Conversion

The physiotwin4d-convert-vtk-to-usd command converts VTK, VTP, or VTU mesh files to USD for Omniverse visualization. Multiple input files are treated as an ordered time series by default; pass --static-merge to instead merge unrelated static meshes into one scene with no time samples.

Basic Usage

physiotwin4d-convert-vtk-to-usd heart.vtp \
    --output heart.usd

Time Series

physiotwin4d-convert-vtk-to-usd heart_*.vtp \
    --output heart_animation.usd \
    --fps 30

Appearance Options

Solid color:

physiotwin4d-convert-vtk-to-usd heart.vtp \
    --output heart_red.usd \
    --appearance solid \
    --color 1 0 0

One anatomy material for every mesh:

physiotwin4d-convert-vtk-to-usd heart.vtp \
    --output heart_material.usd \
    --appearance anatomy \
    --anatomy-type heart

A material per structure. Omitting --anatomy-type picks each object’s material from its name, and with --static-merge the objects are named after the structures recorded in each file’s SegmentationLabelNames field data — as written by the image-to-VTK workflow:

physiotwin4d-convert-vtk-to-usd patient_highres_*.vtp \
    --output heart_structures.usd \
    --appearance anatomy \
    --static-merge

Colormap from a VTK point data array:

physiotwin4d-convert-vtk-to-usd frame_*.vtk \
    --output stress.usd \
    --appearance colormap \
    --primvar vtk_point_stress_c0 \
    --cmap viridis \
    --intensity-range 0 500

Splitting

By default, meshes are split by connected component. Use --no-split to keep one mesh, or --by-cell-type to split by cell type.

physiotwin4d-convert-vtk-to-usd mesh.vtu \
    --output mesh.usd \
    --by-cell-type

Python API

Use physiotwin4d.WorkflowConvertVTKToUSD for the workflow API (splitting and appearance built in) and physiotwin4d.ConvertVTKToUSD for lower-level control (e.g. anatomical label splitting via mask_ids). Both take in-memory PyVista/VTK meshes.