# Geometric Constraint Solver

Previous GSoC projects have made progress towards a parametrics/constraint library. Please check libpc Developer Doc as well as the libpc source. For this year's project, we're suggesting a specific direction as outlined below.

BRL-CAD does not presently provide the means to specify values that are undetermined or otherwise dependent calculations. That is to say that there is no support for constraints and parametrics such that a modeler can define a sphere such that the sphere's radius necessarily maintains tangency with a given planar surface. This task would focus on implementing basic support for this feature in the BRL-CAD geometry format. Parametric representation of Geometry (and constraints) provides a good foundation for various aspects of Design computation, Geometry Generative Algorithms, and A more logically connected model not to mention significant reduction in Modeling time (since the process of modeling during an actual design cycle is inherently iterative).

Since the initial work on libpc began, the open source gecode constraint solver has released version 4.0 with support for floating point data types. The work to be done is to put gecode's constraint solver "underneath" the libpc API in place of the existing solver and demonstrate successful soltions to primitive constraint equation systems. (Discuss these with the BRL-CAD developers.)

# References

- http://www.gecode.org/
- http://www.gecode.org/doc-latest/reference/classCartesianHeart.html
- src/libpc
- include/pc.h
- src/librt/primitives/table.c
- contains primitive callback definitions

- src/librt/primitives/**
- each primitive needs to implement a routine that returns available parameters, rt_*_param().

Requirements:

- Familiarity with C/C++
- General understanding of constraint solving