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

[Patrick Shriwise]

Evan,

Spot on. We got it working after adjusting the cubit flag to 
TORUS_SURFACE_TYPE.

Seems like this is a problem from 13.1 on as I had the same issue in 
Cubit 14....


Cheers,

Patrick

On 07/28/15 11:21, Vander Zee, Evan B. wrote:
>
> Andy,
>
> I reproduced your problem using a version of CGM that I built on 
> Cubit13.1.  After some experimentation, I think that the problem is 
> that the GeometryType is off by one in CGMA from what the Cubit 
> library expects.  I got successful RefFaces when passing arguments 
> CONE_SURFACE_TYPE (which I am guessing is interpreted as the one-later 
> enum value PLANE_SURFACE_TYPE) and TORUS_SURFACE_TYPE (which I am 
> guessing is interpreted as the one-later enum value 
> BEST_FIT_SURFACE_TYPE).
>
> We ought to fix the off-by-one error, but for now just the information 
> I’ve given will probably help you with whatever you are doing.
>
> I’m not sure which value would have to be removed/renumbered to get 
> CGMA to agree with Cubit.  Is anyone else familiar with the 
> GeometryType enumeration?  I’m just making my best guess here . . .
>
> -Evan
>
> *From:*Vander Zee, Evan B.
> *Sent:* Monday, July 27, 2015 4:48 PM
> *To:* cgma-dev at mcs.anl.gov
> *Cc:* Patrick Shriwise; 'Andrew Davis'
> *Subject:* RE: [cgma-dev] Why can't I create surfaces from curves
>
> It is a little hard to tell exactly what you are trying to do, but it 
> looks like you are trying to create a circular patch in the y-z 
> plane.  I tried running the code you provided with OCC geometry 
> engine, and I got no errors.
>
> Some things you could try would be giving more than two edges and 
> linking edges better in a loop, i.e., making sure that the end vertex 
> of one edge is the beginning vertex of the next. I planned to try 
> these, but my only successful build of CGM with acis so far is a cmake 
> build, and I’m still a novice in the cmake build system, so I didn’t 
> get far enough to reproduce the problem.  What version are you using?
>
> -Evan
>
> *From:*cgma-dev-bounces at mcs.anl.gov 
> <mailto:cgma-dev-bounces at mcs.anl.gov> 
> [mailto:cgma-dev-bounces at mcs.anl.gov] *On Behalf Of *Andrew Davis
> *Sent:* Monday, July 27, 2015 10:01 AM
> *To:* Patrick Shriwise
> *Cc:* Andrew Davis; cgma-dev at mcs.anl.gov <mailto:cgma-dev at mcs.anl.gov>
> *Subject:* Re: [cgma-dev] Why can't I create surfaces from curves
>
> Hi Patrick
>
> Irrespective of whether or not I use planar, best fit, sphere, its the 
> same error message over and over again.
>
> Thanks
>
> Andy
>
> On Sat, Jul 25, 2015 at 8:00 AM, Patrick Shriwise <shriwise at wisc.edu 
> <mailto:shriwise at wisc.edu>> wrote:
>
> Hey Andy,
>
> The error message seems to indicate it's trying to make a surface 
> which isn't planar.. maybe thats a good starting point? Are there 
> other flags to hand that function by chance?
>
> Cheers,
>
> Patrick
>
> On 07/23/2015 02:34 PM, Andrew Davis wrote:
>
>     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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