Stitch cavities in meshes in SketchUp

Stitcher.rb

class DynameshTool
  def initialize
	end

	def sort_vertices(v1,v2,orientation,direction,view)
		coords = [v1,v2].collect{|v|
			pos = view.screen_coords(v.position)
			case orientation
			when :horizontal 	then pos[0]
			when :vertical		then pos[1]
			end
		}
		if (coords[0] > coords[1])
			v1, v2 = v2, v1
		end
		if direction == :more
			return v2, v1
		else
			return v1, v2
		end
	end

	def onKeyUp(key, repeat, flags, view)
		selection = Sketchup.active_model.selection
		edge = selection[0]
		case key
		when VK_LEFT	then orientation, direction = :horizontal, :less
		when VK_RIGHT	then orientation, direction = :horizontal, :more
		when VK_DOWN	then orientation, direction = :vertical,	 :more
		when VK_UP		then orientation, direction = :vertical,	 :less
		end

		v1, v3 = sort_vertices(	edge.start,
														edge.end, 
														orientation, 
														direction, 
														view)
		
		next_edge = v1.edges.find{|e|
			e != edge && e.faces.length == 1
		}
		v2 = next_edge.other_vertex(v1)
		face = Sketchup.active_model.entities.add_face([v1,v2,v3].collect{|v|v.position})
		new_edge = (face.edges - [edge,next_edge]).first
		selection.clear
		selection.add new_edge
	end
end