test line/volume intersection

demos/boolean/intersect_line_volume.geo

+
+SetFactory("OpenCASCADE");
+
+Geometry.LineNumbers = 1;
+
+xw_ = 0.1; yw_ = 0.1;
+s_wire = news;
+Rectangle(news) = {-xw_, -yw_, 0.,  xw_,  yw_, 0.};
+l_wire[] = Abs(Boundary{Surface{s_wire};});
+Delete{ Surface{s_wire}; } // Surface s_wire is deleted to keep only its boundary
+Printf("init: l_wire[] = ", l_wire[]);
+
+DefineConstant[
+  flag_Symmetry_X = { 0, Choices{0,1}, Name "Symmetry X0-plane" }
+  flag_Symmetry_Y = { 0, Choices{0,1}, Name "Symmetry Y0-plane" }
+  flag_Symmetry_Z = { 0, Choices{0,1}, Name "Symmetry Z0-plane" }
+];
+
+dx = 0.4; dy = 0.4; dz = 0.4;
+x_min_ = (flag_Symmetry_X)? 0. : -dx/2;
+y_min_ = (flag_Symmetry_Y)? 0. : -dy/2;
+z_min_ = (flag_Symmetry_Z)? 0. : -dz/2;
+
+v_box=newv;
+Block(newv) = {x_min_, y_min_, z_min_,  dx/2, dy/2, dz/2};
+
+
+l_wire[] = BooleanIntersection { Line{l_wire[]}; Delete; }{ Volume{v_box}; };
+SyncModel;
+Printf("after intersection: new l_wire[] = ", l_wire[]);