HB-Aperture Plane-XY Axes Varies with Surface Orientation?

edpmay · May 20, 2024, 9:16pm

Hi all,

I am running into a weird issue, and not sure if its a bug, or the intended behavior?

When creating Honeybee Apertures in Rhino, the XY Axis of the Aperture geometry’s Plane seems to flip, depending on the ‘direction’ of the face in Rhino? That is very surprising to me? I would assume that the Aperture XY would match the Rhino XY?

If I just visualize the XYZ-Axes of the original Rhino geometry, and the Aperture Geometry (note: the aperture is offset for clarity) note that the X and Y Axes flip as I rotate the rhino-geometry about the world-Y:

That seems really odd to me - isn’t it? Or is there some reason that the XY axis flips like that depending on the surface’s original normal direction?

This uncertainty/variability in the geometry’s XY-Axes is causing issues with some later uses where I’m sorting, labeling, and ordering aperture elements.

Is there a known way to manage this variability and get the Plane of the Aperture to match the Plane of the input geometry consistently? Example attached for reference.

thanks!!
@edpmay

aperture_example.gh (20.9 KB)

chris · May 24, 2024, 5:06am

Hey @edpmay ,

The XY axis of the Aperture plane in the honeybee object originates from the UV plane of the Rhino surface. You can see that this happens on this line of the source code:

github.com

ladybug-tools/ladybug-rhino/blob/master/ladybug_rhino/togeometry.py#L241


      
                      lb_face = Face3D(all_verts)
                      if lb_face.area != 0:
                          faces.append(lb_face)
          else:  # convert each Brep Face to a Face3D
              meshing_parameters = meshing_parameters or rg.MeshingParameters.Default
              if not isinstance(geo, rg.Brep):  # it's likely an extrusion object
                  geo = geo.ToBrep()  # extrusion objects must be cast to Brep in Rhino 8
              for b_face in geo.Faces:
                  if b_face.IsPlanar(tolerance):
                      try:
                          bf_plane = to_plane(b_face.FrameAt(0, 0)[-1])
                      except Exception:  # failed to extract the plane from the geometry
                          bf_plane = None  # auto-calculate the plane from the vertices
                      all_verts = []
                      for count in range(b_face.Loops.Count):  # Each loop is a boundary/hole
                          success, loop_pline = \
                              b_face.Loops.Item[count].To3dCurve().TryGetPolyline()
                          if not success:  # Failed to get a polyline; there's a curved edge
                              loop_verts = _planar.planar_face_curved_edge_vertices(
                                  b_face, count, meshing_parameters)
                          else:  # we have a polyline representing the loop

Translating the Aperture geometry back into Rhino breps will erase the original plane since we do not pass this to the Rhino breps that is created on this line of code:

github.com

ladybug-tools/ladybug-rhino/blob/master/ladybug_rhino/fromgeometry.py#L134


      
          
          def from_mesh3d(mesh):
              """Rhino Mesh from ladybug Mesh3D."""
              return _translate_mesh(mesh, from_point3d)
          
          
          def from_face3d(face):
              """Rhino Brep from ladybug Face3D."""
              segs = [from_linesegment3d(seg) for seg in face.boundary_segments]
              try:
                  brep = rg.Brep.CreatePlanarBreps(segs, tolerance)[0]
              except TypeError:  # not planar in Rhino model tolerance; maybe from another model
                  print('Brep not planar in Rhino model tolerance. Ignoring tolerance.')
                  try:
                      brep = rg.Brep.CreatePlanarBreps(segs, 1e6)[0]
                  except TypeError:  # it must be a zero-area geometry
                      return None
              if face.has_holes:
                  for hole in face.hole_segments:
                      trim_crvs = [from_linesegment3d(seg) for seg in hole]
                      brep.Loops.AddPlanarFaceLoop(0, rg.BrepLoopType.Inner, trim_crvs)

So the reason why the XY axis might not make sense is because it is being regenerated from the vertices.

Use Aperture.geometry.plane if you want something with an XY plane that follows the original UV grid of the Rhino surface.

edpmay · May 24, 2024, 1:55pm

ah! I see. Thanks @chris !

best
@edpmay