User:Barche/STEP importer

From K-3D

STEP is a common file format used in CAD applications. A prototype STEpMeshReader is currently commited to modules/opencascade, and uses the OpenCascade toolkit to parse the files and convert all geometry to trimmed NURBS. Below are some renders and screenshots from the sample files that come with OpenCascade.

Status

The OpenCascade importer mostly works, except on certain surfaces of revolution that do not have parameters in the interval (0, 2pi). It relies on the OpenCascade BREP-to-NURBS conversion routines, which unfortunately do not produce a very clean result. For cleaner STEP importing, a better solution would be to directly parse the STEP file, and convert everything to NURBS using K-3D.

Building

If you are bold enough to try building this plugin at this time, note that it is untested on win32. On linux, OpenCascade 6.3 should work, provided you point CMake to the correct header and library dirs (after enabling the OpenCascade plugin).

Results

Screw preview: The simplest example included in OpenCascade appears to work.	Screw render: Aqsis render.
Linked rods preview: A more complicated example, with some badly behaved surfaces. Some problems become apparent, and orbiting causes random crashes.	Linked rods render: The Aqsis render looks fine, on the other hand.
Linked rods preview: IGES formula 1 car, from the OpenCascade website. Some holes appear in the preview, but otherwise it behaves fine.	Linked rods render: The Aqsis render.