Here is a list of possible constraints we may want to try to support in dyna3. Those labeled with a (?) might be tricky or impossible express as a polynomial equation in the coordinates of the entities.

• A point lies on an entity
• One entity is contained in another
  • (?) For some entities, like a point and a ball (as opposed to a sphere), this may be an inequality constraint.
• Two entities are tangent
• Two entities coincide
• Two entities are at a fixed distance
• Two entities make a specific angle
• Two entities intersect
  • (?) Or do not intersect—although this would be an inequality constraint.
• The position of an entity is fixed at a specific value
• The measure of an entity is fixed at a specific value
  • For different entities, measure might mean length, area, volume, angle, dihedral angle, solid angle...
• Two entities are congruent
  • Is this just a conjunction of some automatically-generated conjunction of some of the above?
• Some polynomial equation in the measures or positions of an entity or entities holds
  • That is, we may want to allow direct entry of an arbitrary polynomial constraint.
  • For example, dist(a,b) + dist(b,c) = k would constrain b to lie on an ellipsoid with foci a and c.

Definitely feel free to add items!