CGAL users discussion list

[Bryn Lloyd <>]

Dear CGAL/Mesh_3 users and developers

I have an implicit domain oracle (derived from Labeled_mesh_domain_3) 
with 1D features.
When I add features to my domain, make_mesh_3 sometimes does not 
discover my domain at all. Without the features the domain is discovered 
(usually).


Digging into the code of make_mesh_3 I noticed the strategy to add 
initial points seems very different for a mesh with features 
(init_c3t3_with_features) compared to one without features (init_c3t3).
This is how I understand it:

No features:
 - segments between random points on sphere and "center" are 
intersected with domain - intersection points are added to C3T3

With features:
   - features (0D,1D) are sampled and points added to C3T3 with 
"protecting balls"

Conclusions:
- So it seems the code for domains with features might oversee (partial) 
regions with no features.
- Also, I guess, if a point on a feature is considered "outside" by the 
oracle, instead of on a surface patch, regions/domains will be missed.


How to solve this?
- Would it make sense to run the initialization code to add feature 
points and the add my own internal (dimension=3) points?
- How should I add these points? Can I add the points via 
C3T3::insert(Point), or should I add them via the 
C3T3::insert(Weighted_point)
- What weight/ball radius should I use? I don't really want to enforce 
these points, but want to help the oracle discover the domains.

Thanks for any suggestions/help
Bryn