Component Instance glued to face within a group

The API implies that Components can only be glued to faces.
However, a component instance that is not in a group can be glued to a face inside that group.
(Also a component instance can be glued to a face inside a different component instance.)
So the method: componentInstance.glued_to can return either a face, a group, or another component.
What’s the easiest way to find the actual face inside the group (or other instance) that the instance is actually glued to?

Actually all I need is the face normal, so I could create a vertical vector, use it to create a vertical cline, transform the cline using the instance transform, then find the resulting cline direction. I think I answered my own question.

Not sure what you really want, but an illustration might help:


Great. That’s much better. I knew that method but didn’t connect the dots.
But I also need the plane of the face. I don’t see a straightforward way to get that.
Do you?

Geom module said:

A plane can be represented as either an Array of a point and a vector, or as an Array of 4 numbers that give the coefficients of a plane equation.

normal = inst.transformation.zaxis
point  = inst.transformation.origin
plane  = [ point, normal ]

I’m not sure if I understand the question, but the “Face” class includes methods for “normal” and “plane”. Instead of “[point, normal]”, the plane value is the OTHER kind (an array with four values). The return values will be relative to the local coordinate system.

Dan’s answer is what I need. (I must have had some stupid pills this morning.)

Bruce: I cannot access the face methods because componentInstance.glued_to doesn’t return a face if the face is inside a group.and the instance is not in that group.

… of course my example makes bug assumptins, that the instance’s origin will be ON the face’s plane.

Try using a pickhelper (untested).

  # Get the glued_to face's plane

  view = Sketchup::active_model.view
  inpt = inst.transformation.origin
  x, y = view.screen_coords(inpt)
  ph   = view.pick_helper

  ph.do_pick(x, y)
  ents = ph.all_picked
  target = inst.glued_to
  if target.is_a?(Sketchup::Group)
    ents.delete_if{|e| e.parent != target }
    ents.delete_if{|e| e.parent != target.definition }
  # now ents should just have what is glued_to

  face = ents.find{|e|
    e.is_a?(Sketchup::Face) &&
    e.classify_point(inpt) != Sketchup::Face::PointUnknown &&
    e.classify_point(inpt) != Sketchup::Face::PointNotOnPlane 
  if face # nil if not found
    # use the face
    plane = face.plane