[cgma-dev] Why can't I create surfaces from curves

[Andrew Davis]

Hi Guys

I have the following function that I've added to my version of iGeom,

ITAPS_API void
iGeom_createSurface2(iGeom_Instance instance,
    /*in*/ iBase_EntityHandle *input_curves,
    /*in*/ int num_curves,
    /*out*/ iBase_EntityHandle *geom_entity,
                    int* err)
{
  CubitVector p1(0, 0, 5);
  RefVertex* v1 = gmt->make_RefVertex(p1);

  CubitVector p2(0, 0, -5);
  RefVertex* v2 = gmt->make_RefVertex(p2);

  CubitVector p3(0, 5, 0);
  RefVertex* v3 = gmt->make_RefVertex(p3);

  CubitVector p4(0, -5, 0);
  RefVertex* v4 = gmt->make_RefVertex(p4);

  RefEdge* e1 = gmt->make_RefEdge(ARC_CURVE_TYPE,v1,v2,&p3);
  RefEdge* e2 = gmt->make_RefEdge(ARC_CURVE_TYPE,v1,v2,&p4);

  DLIList<RefEdge*> curves;
  curves.insert(e1);
  curves.insert(e2);

  RefFace* tmp_surface =  gmt->make_RefFace(PLANE_SURFACE_TYPE,
    curves,
    false);

  *geom_entity = reinterpret_cast<iBase_EntityHandle>(tmp_surface);
  RETURN ((tmp_surface ? iBase_SUCCESS : iBase_FAILURE));
}

When I run this, I can sucessfully create the vertices, and create curves
from those verts using make_RefEdge. When I try to create a surface from
those two ref edges I get the following error.

WARNING: In AcisGeometryEngine::make_FACE
         At this time, cannot make a FACE that isn't planar or best fit.
ERROR: In AcisModifyEngine::make_Surface
       Cannot make Surface object.
ERROR: Couldn't make new RefFace.

If I save the file as acis and examine the results in Cubit, they appear as
they should (minus the surface). I can, in Cubit, make surface then, sweep
and do all the operations that I want to.

Is there something that I', just misunderstanding about CGM / gmt that
means I'm using this wrong?

Thanks

Andy
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