[Bf-committers] Implicit Surface Nodes

[joe]

Hi all.  I've been working on a pynode proof-of-concept for an
implicit surface node system (basically, node-based metaball
surfaces).

This network:
http://www.pasteall.org/pic/91966

Produced this surface:
http://www.pasteall.org/pic/91967

It's a little hard to read the network since I've not finished group
nodes yet (which I plan on using to implement higher-level, more
artist-friendly nodes).  Basically, all it's doing is calculating a
(crude) metaball cube, using perlin noise to warp the domain space.
The nodes are designed to form extremely simple symbolic expression
trees, the idea being to generate code for a GPU marching cubes
tessellator.  These trees are designed to be symbolically
differentiated; you can see a 'Scalar Derivative' node in that
network, it does not use finite differences.

I'll be publishing the code soon (everything is done in python as an
add-on).  I still need to work out the details of how these nodes will
be tied to scene objects, and I don't have a working implementation
yet of the fancy marching cubes algorithm (dual grid) you use for
hard-edged objects ( :( ).  Anyway, I just thought I'd share.

Best,
Joe