A simple implicit modelling test system scriptable in Scheme.

It is based on my sample 3D framework, which uses Qt and OpenMesh, while tessellation is done with my dual contouring library. Alternative tessellation is done with my marching cubes library or a wrapper on Jules Bloomenthal's polygonizer. Scripting support is added via Guile.

Usage

The only extra commands are show, mc and bl. The original display function was show, which uses a kind of dual contouring:

(show <distance-function> <bounding-box> <resolution>)

Here distance-function is a function that takes a 3D point (a list of 3 numbers) and returns its signed distance to the implicit surface. The bounding box is given as a list of two points, representing the minimum and maximum corners, and resolution is an integer which corresponds to the number of quads on an edge when the bounding box is a cube (the actual resolution is always adjusted to the aspect ratio of the bounding box).

Alternatively, mc uses marching cubes:

(mc <distance-function> <bbox-center> <radius> '(<min-depth> <max-depth>))

This tessellates the surface in a regular axis-aligned box centered at bbox-center, and having edges of length 2*radius. Evaluation is adaptive, with the given minimum and maximum depth values.

Finally, Bloomenthal's polygonizer has a very similar API:

(bl <distance-function> <bbox-center> <radius> <resolution>)

See example.scm for an example.