- Any object cannot lie upon each other
- Multiple points cannot be defined at the same location. Initial and final points of a closed curve must be defined using the same point. Picture 1 below.
- A point cannot lie on a curve without being its definition point (except the parametric point).
- A point where two curves intersect (or touch) must be a definition point of both curves (must be a part of the Geometry). *) Picture 2.
- Surface can lie inside of the other Surface. **) Picture 3.
- Surfaces cannot partially cover each other Picture 4 and Picture 5.
- Surfaces can touch each other (in a point or on a boundary line) only if both surface lie in the same plane Picture 6.
- Solid cannot touch another Solid in a point or line (edge) Picture 7.
- Solid can touch another solid only in a common surface. ***)
- Solid cannot intersect another Solid or be partially inside another one as long as the common Surfaces are not definition Surfaces of both Solids.
- Solid can be inside another solid only if it is defined as Integrated object of the bigger one.
- All above mentioned errors in definition of the non-manifold Geometry can be automatically solved using the command Repair Geometry (Tools->Repair Geometry).
*). This point can be found automatically using commands Intersect Lines (Tools->Intersect Lines or Intersect Lines from the Edit Bar) or Repair Geometry (Tools->Repair Geometry).
**). In this case one needs to first create an internal Hole in the first bigger Surface and then insert the second Surface into this hole. This process can be recursive, i.e., it is possible to crease a Hole in the internal Surface and insert an additional Surface there). When defining a new Surface graphically (e.g., using a rectangle), HYDRUS recognizes when the new Surface is located inside of the existing Surface and automatically offers their integration.
***) One should use the technique described in 2)
