# Advanced Sketch Primitive Editor

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. So we don't have a way to constrain (for example) a line segment to remain at a fixed angle relative to another line segment during editing.

This task would focus on implementing basic support for this feature in the context of BRL-CAD's sketch primitive. Options include:

- Integrate existing BSD licensed 2D constraint solving functionality from exising projects:

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. This is likely to require refactoring psketcher and/or sketchsolve, but they do provide a starting point.

- Once a solving framework is in place and working with BRL-CAD sketch objects, test out the Gecode constraint solver by defining the 2D constraints from the above solvers in the Gecode framework - see how its solving speed compares to the dedicated 2D solutions, and how straightforward it is to use Gecode to solve such problems.

This task is related to the more general parametric constraint tasks, but it is more narrowly scoped and more focused on immediately user visible features.

# References[edit]

- https://code.google.com/p/psketcher/
- https://code.google.com/p/sketchsolve/
- http://www.gecode.org/
- http://www.gecode.org/doc-latest/reference/classCartesianHeart.html
- src/librt/primitives/sketch
- contains sources pertaining to BRL-CAD's 2D sketch primitive

Requirements:

- Familiarity with C/C++