An Interactive Three-Dimensional Volume Visualization Pipeline for Fusion Simulation Data in Unreal Engine and Omniverse

We present an end-to-end pipeline that delivers gyrokinetic scalar fields into Unreal Engine and NVIDIA Omniverse, with three key advances. The first is the render time, native coordinate sampling of curvilinear structured grid fields, as exemplified by gKPSP on (r,θ,φ), in both real-time engines, removing the intermediate Cartesian resampling pass. The second is the joint use of OpenVDB and OpenUSD as an engine-neutral intermediate representation between the solver output and the two engine front ends. The third is an interactive in-engine inspection through threshold window filtering, clip box dissolution, transfer function tuning, and arbitrary cross-section planes, with the native coordinate scene sustaining interactive rendering on a single graphics processing unit workstation.The enabling mechanism is an inverse engine XYZ–to-toroidal map evaluated at every ray sample, returning each sample to the simulation frame before the structured grid lookup. The same map was implemented independently in the material, scientific renderer, and compute kernel layers of the two engines. A quantitative comparison against the Cartesian bounding box baselines showed that the native coordinate representation preserves the structured grid resolution and fine-scale turbulence content, which Cartesian resampling discards, at the cost of a bounded per-sample coordinate conversion overhead. The rendering of fields defined on unstructured high-order meshes is left to future work.