Grenzwert

Grenzwert is a cross-platform medical volume rendering application for visualizing CT scans and other volumetric datasets. It renders volumes with real-time GPU path tracing (Monte Carlo delta tracking with physically based lighting), producing cinematic-rendering-style images, and complements the 3D view with a multiplanar reconstruction (MPR) mode featuring axial, coronal, sagittal and oblique slice planes, a synchronized crosshair, window/level controls, and distance and angle measurements.

The application loads DICOM studies through a Patient/Study/Series browser with a built-in DICOM tag inspector, supports common transfer syntaxes (JPEG, JPEG-LS, JPEG 2000, RLE), and streams large volumes progressively, including over HTTP. Rendering features include an interactive BRDF-based transfer function editor, region-of-interest cropping with 3D gizmo handles, HDR tone mapping, auto-exposure and bloom.

Grenzwert runs natively on Windows (Direct3D 11/12), macOS (Metal) and Linux (Vulkan), and in the browser as a WebAssembly + WebGPU build that can be tried without installation. It is intended for research, education and visualization purposes and is not certified for clinical diagnostic use.