OFFtoVRLM v0.2 released

After a couple of changes, this prototype is now able to generate VRML code with explicit edges and showing both vertex and face normal for models with a large number of triangles. For instance, the Stanford Bunny with 70K polygons is processed in less then ten seconds, generating a 16.5MB VRML file containing the mesh and showing its convex hull, bounding box and sphere, polygon edges and normals at faces and vertices. A larger file, the 345K polygons Armadillo, is processed in around fifty seconds, generating a 70MB VRML file.

For illustration purposes we processed the 'Dino' model from AIM@SHAPE shape repository. It has around 50K polygons and below I show a couple of snapshots of the resulting VRLM model, containing normals and explicit edges.

The current stable version of the prototype is available for download [ZIP 118KB].

VRML model of 'Dino'

Close-up illustrating the normals and polygon edges

Computing the 3D convex hull

As a new optional functionality of the OFF to VRML converter, I coded the extraction of the convex hull of a 3D shape based on the implementation of the incremental algorithm proposed by O'Rourke in "Computational Geometry in C". Despite the clear explanation of the algorithm and included code, it took me some time to adapt it to the data structure I am using. However, the expected result were achieved.

3D model and corresponding convex hull.