Error in ShapeGeometryMeshOf() method about xbimgeometry

[martin1cerny]

Have a look at source code for IfcStore.SaveAsWexBim() function. That uses triangulated geometry to create data for a web presentation.

[jv112602]

I had the same issue and used some code I posted in https://github.com/xBimTeam/XbimGeometry/issues/34
if you need more just let me know but I was able to get all the vertices and faces with that technique

Jay

[ani-rudh]

Hi Jay,

Yes please. I infact tried your method first from the code in issue 34.

This is what I am doing..

var context = new Xbim3DModelContext(model);
              context.CreateContext();
             

              var item = model.Instances.FirstOrDefault<IIfcWall>();
              var productshape = context.ShapeInstancesOf((IIfcProduct)item);
                  
              var _productShape = productshape.Where(s => s.RepresentationType != XbimGeometryRepresentationType.OpeningsAndAdditionsExcluded).ToList();

              XbimShapeTriangulation mesh = null;
              foreach (var shapeInstance in _productShape)
              {
                  var geometry = context.ShapeGeometry(shapeInstance.ShapeGeometryLabel);
                  Console.WriteLine(geometry.Format);
                  Console.WriteLine(context.ShapeGeometry(shapeInstance.ShapeGeometryLabel));
                  var ms = new MemoryStream(((IXbimShapeGeometryData)geometry).ShapeData);
                  var br = new BinaryReader(ms);
                  mesh = br.ReadShapeTriangulation();
                  mesh = mesh.Transform(((XbimShapeInstance)shapeInstance).Transformation);
                  Console.WriteLine (mesh.Faces.Count());

                  
              }

I get 6 faces returned on the wall. The wall is a simple cubiod. From what I understand, after triangulation, each face is split to 2 triangles, which implies that the triangulate shape will have 12 faces on a cuboid instead of 6.

I want to extract the data of each geometry in such a way that i have reference to TriangleIndices, Vertices of the triangle and Face indices for all the faces of the geometry.

If you are familiar with Unity, these are the inputs to compile a mesh. I need to recreate the IFC file in Unity with the hierarchy intact.

I await your suggestions if there is a better way to do this.

On a side note, I have tried the read() method in XbimWindowsUI/Xbim.Presentation/MeshGeometry3DExtensions.cs, which I couldn't manage as well.

Thanks in advance Jay!

[martin1cerny]

If you tried little bit more you would find that every of these faces has triangles as normals and indices inside.

var triangleCount = mesh.Faces.Aggregate(face => face.TriangleCount);

[ani-rudh]

Oh yes. Thank you so much :). Found it now.

…

On Mar 15, 2017 5:02 PM, "Martin Černý" ***@***.***> wrote: If you tried little bit more you would find that every of these faces has triangles as normals and indices inside. var triangleCount = mesh.Faces.Aggregate(face => face.TriangleCount); — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#44 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AOnwR8kx8vMlb7Hj0DQhxe8uMNJE2RuUks5rmAuIgaJpZM4MdQjQ> .

[jv112602]

I tried your same cube example and got the following:

• 6 faces which are all the sides of the cube
• inside each cube side (face) you have 2 triangles
• then there are 6 indices inside each cube face representing the 6 indices for the sides of the 2 triangles
• I think you can group the indices into 3's and you have your triangle indices ?
  triangle 1 has indices[0, indices[1], indices[2]
  triangle 2 has indices[3, indices[4], indices[5]

make sense ?

jay

[ani-rudh]

Yes Jay, I was quiet dumb not try one step further! Thanks, it works. On Mar 17, 2017 19:25, "jay vose" <[email protected]> wrote: I tried your same cube example and got the following: - 6 faces which are all the sides of the cube - inside each cube side (face) you have 2 triangles - then there are 6 indices inside each cube face representing the 6 indices for the sides of the 2 triangles - I think you can group the indices into 3's and you have your triangle indices ? triangle 1 has indices[0, indices[1], indices[2] triangle 2 has indices[3, indices[4], indices[5] make sense ? jay — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#44 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AOnwR4PLRg4wvEsX8TksR-iBqQorqb-nks5rmtANgaJpZM4MdQjQ> .