[Gmsh] opencascade: union, disregard seams

[Christophe Geuzaine]

> On 8 Dec 2017, at 16:24, Nico Schlömer <nico.schloemer at gmail.com> wrote:
> 
> Hi everyone,
> 
> When combining two domains using an opencascade union, the seams will still be respected by the mesher. As an example, check out the geometry of a union of two overlapping circles:
> ```
> SetFactory("OpenCASCADE");
> s0 = news;
> Disk(s0) = {-5.0, 0.0, 0.0, 10.0};
> s1 = news;
> Disk(s1) = {5.0, 0.0, 0.0, 10.0};
> bo1[] = BooleanUnion{Surface {s0}; Delete;} {Surface {s1}; Delete;};
> ```
> After the meshing process, the outlines of both circles are still recognizable.
> 
> Is it possible to give the mesher the freedom to disregard the outlines?
> 

With the latest snapshots, do:

SetFactory("OpenCASCADE");
s0 = news;
Disk(s0) = {-5.0, 0.0, 0.0, 10.0};
s1 = news;
Disk(s1) = {5.0, 0.0, 0.0, 10.0};
bo1() = BooleanUnion{Surface {s0}; Delete;} {Surface {s1}; Delete;};
Compound Surface{bo1()};

Note that this relies on the new Compound implementation, which will still undergo major changes until it is released in Gmsh 3.1 or Gmsh 4.0, hopefully early next year.

Christophe

PS: have a look at the new Python API (see demos/api/*.py), which you might find useful.


> Cheers,
> Nico
> _______________________________________________
> gmsh mailing list
> gmsh at onelab.info
> http://onelab.info/mailman/listinfo/gmsh


-- 
Prof. Christophe Geuzaine
University of Liege, Electrical Engineering and Computer Science 
http://www.montefiore.ulg.ac.be/~geuzaine

Free software: http://gmsh.info | http://getdp.info | http://onelab.info