Geometric Constraint Solver

Revision as of 18:52, 2 March 2014 by Starseeker (talk | contribs) (Rework constraint solver task)

BRL-CAD supports many primitives, including a 2D sketch primitive, but we do 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 or (in the 2D case) that a line segment must remain at a fixed angle relative to another line segment.

This task would focus on implementing basic support for this feature in the BRL-CAD geometry format. Past work has focused on a full, generic constraint system for 2D and 3D modeling. For this year's task, we are proposing a slightly different approach to the problem, with more "incremental" steps towards the final goal:

In particular, psketcher offers some Qt visualizations of sketch editing - a good "first step" would be to make a "Qt sketch editor" for BRL-CAD's sketch objects.

  • If Gecode proves viable, begin expressing 3D constraints.



  • Familiarity with C/C++

Note: Previous GSoC projects have made some progress towards a parametrics/constraint library. Please check libpc Developer Doc as well as the libpc source. While it is certainly a viable route to pick up where those efforts left off, the above approaches are likely to require less "up front" work for visible results.