[Gmsh] OpenCASCADE boolean operation with compound volume

[Lionel Wilhelm]

Dear Gmsher's,

I have a problem making boolean operations on compound volumes. I 
attached a small example that illustrate the problem. I have two boxes 
sharing a face and a sphere intersecting both boxes. I would like to 
substract the sphere from both boxes.

My idea was first to assemble/merge the boxes with the Compound Volume 
command and then use the BooleanDifference operation.

At the step of the boolean operation, GMSH complain telling  : "Error   
: Unknown OpenCASCADE entity of dimension 3 with tag 28" but if I have a 
look in Tools->Visibility the entity with tag 28 is the volume I want...

Does any of you have a hint ?

Kinldy,

Lionel Wilhelm

-------------- next part --------------
// Gmsh project created on Tue Dec 12 13:24:46 2017
SetFactory("OpenCASCADE");

// Create an empty list to store the individual boxes id.
boxes = {};

//create a new box
boxes += newv;
Box(boxes[0]) = {0,0,0,2,2,1};

//create another box
boxes += newv;
Box(boxes[1]) = {0,0,0,-2,2,3};

// create a sphere
sphere = newv;
Sphere(sphere) = {0,1,1,0.5};

// assemble the two boxes
twoboxes = newv;
Compound Volume(twoboxes) = {boxes[]};

// substract the sphere from the boxes
BooleanDifference{Volume{twoboxes};}{Volume{sphere}; Delete;}