Rotating faces to create a u-shape

j_jones

Hello, I am just learning the Ruby API and have a hopefully simple question.

My goal is to draw a face in an arbitrary point in space (not at the origin). Then I want to copy the face and rotate it 90 degrees to create a corner shape. Then copy the second face and rotate it 90 degrees to create a u-shape

This is some example code I came up with to do this, however, I'm running into a problem in that I can't seem to access the points of the rotated face. The positions of the points are identical the ones in the original face for some reason and do not reflect the transformed shape.

Here is the script.



model = Sketcup.active_model
active_entities = model.active_entities

# draw first face

#     p3         p2 
#      +---------+
#      |         |
#      |         |
#      |         |
#      |         |
#      +---------+
#     p0         p1

model.start_operation("first face",true,false,true)

pts = [[10,10,0], [20,10,0], [20,10,10], [10,10,10]]
pt0, pt1, pt2, pt3 = pts
group1 = active_entities.add_group
g1_entities = group1.entities
face1 = g1_entities.add_face(pts)

# print out the vertexes of the first face
puts("first group")
group1.entities.each do |thing|
   if thing.is_a?(Sketchup;;Edge)
     puts "#{thing.start.position} #{thing.end.position}"
   end
end

# end of first face
model.commit_operation

So far so good, here is the face, ready to go

first face

Now on to the second face



model.start_operation("second face",true,false,true)

# make a copy of the first face
# then rotate it to create a corner shape

#            pt0 
#             +---------+
#            /|         |
#           / |         |
#          /  |         |
#         +   |         |
#         |   +---------+
#         |  /pt3
#         | /
#         |/
#         +  

group2 = group1.copy
g2_entities = group2.entities

axis = pt0.vector_to(pt3)
angle = -90.degrees
xform = Geom;;Transformation.rotation(pt0, axis, angle)
group2.transform!(xform)

# notice that the points of the group2 face have not been rotated
#   they still reflect the points of the first face
puts("second group")
group2.entities.each do |thing|
   puts thing
   if thing.is_a?(Sketchup;;Edge)
     puts "#{thing.start.position} #{thing.end.position}"
   end
end
# end of second face

model.commit_operation

Second face rotated, looks good except if I query the second face for the positions of its vertices, it just reports the same positions as the first face.

second face

By the way, I must be doing something really weird because when I run this script in Ruby Console Plus, it freezes and then goes blank. I haven't had any trouble with the console until I ran this script! I guess it's because I really should put all this logic into a module or class instead of just in the global namespace.

Now I would like to rotate the second face to create a u-shape, but I don't know what points to pick because the points given don't reflect the rotation



model.start_operation("third face",true,false,true)

# make a copy of the second face
# then rotate it to create a u-shape
group3 = group2.copy
g3_entities = group3.entities

#         goal 
#             +---------+
#            /|         |
#           / |         |
#          /  |         |
#         +---------+   |
#         |   +-----|---+
#         |  /      |
#         | /       |
#         |/        |
#         +---------+  

# at this point I don't really know which points to choose to create
# the axis for rotating the third face as I don't seem to be able
# to access the rotated shape's actual points?

puts("third group")
group3.entities.each do |thing|
   puts thing
   if thing.is_a?(Sketchup;;Edge)
     puts "#{thing.start.position} #{thing.end.position}"
   end
end
# end of third face

# model.commit_operation

Thanks for any clues
j_jones

j_jones

After some struggles, I came up with this script which "solves" it, however I the ruby console plus crashes about 20 seconds after running this script, I have yet to figure out how to trap that error, whatever it is

link to animated gif demonstration:

https://drive.google.com/file/d/16QQNpN4UhxjZRFghHKzPZY_zYuAYbiHz/view?usp=drive_link

Here is the revised script that at least does what I was trying to do.

The difference is that I used transform_entities instead of transform!
that seemed to have the desired effect on the resulting face so that I could extract it's vertices after the xform. An idea I got from here: https://forums.sketchup.com/t/move-a-group-api-ruby/130338/5


module RotateFaces

  def self.get_face_from_entities(things)
    face = nil
    things.each do |thing|
       if thing.is_a?(Sketchup;;Face)
         face = thing
         break
       end
    end
    return face
  end

  def self.rotate_face(entz, face, axis_pt1, axis_pt2, angle)
    axis = axis_pt1.vector_to(axis_pt2)
    xform = Geom;;Transformation.rotation(axis_pt1, axis, angle)
    entz.transform_entities(xform, face)
    return face
  end
  
  def self.get_face_vertices(face)
    verts = []
    face.outer_loop.vertices.each{|v| verts << v.position}
    return verts
  end

  def self.create_rotated_face(entz, pts, axis_pt1, axis_pt2, angle)
    model = Sketchup.active_model
    active_entities = model.active_entities
    model.start_operation("create rotated face",true,false,true)

    face = self.get_face_from_entities(entz)
    face_xformed = self.rotate_face(entz, face, axis_pt1, axis_pt2, angle)
    verts = self.get_face_vertices(face_xformed)

    model.commit_operation
    return [verts, face_xformed]
  end
end

model = Sketchup.active_model
active_entities = model.active_entities

begin 
  things1 = []
  group1 = active_entities.add_group
  pts1 = [[10,10,0], [20,10,0], [20,10,10], [10,10,10]]
  pt0, pt1, pt2, pt3 = pts1
  g1_entities = group1.entities
  face1 = g1_entities.add_face(pts1)
  puts "face1; ", face1
  puts "group1;", group1

  group2 = group1.copy()
  things2 = RotateFaces.create_rotated_face(group2.entities, pts1, pts1[0], pts1[3], -90.degrees)
  puts "create_rotated_face returned; ", things2
  pts2 = things2[0]
  face2 = things2[1]
  puts "group2;", group2
  # (10", 10", 0")
  # (10", 0", 0")
  # (10", 0", 10")
  # (10", 10", 10")

  group3 = group2.copy()
  things3 = RotateFaces.create_rotated_face(group3.entities, pts2, pts2[1], pts2[2], -90.degrees)
  puts "create_rotated_face returned; ", things3
  pts3 = things3[0]
  fac3 = things3[1]
  # (20", -0", 0")
  # (10", 0", 0")
  # (10", 0", 10")
  # (20", -0", 10")
  puts "group3;", group3

  group4 = group3.copy()
  things4 = RotateFaces.create_rotated_face(group4.entities, pts3, pts3[0], pts3[3], -90.degrees)
  puts "create_rotated_face returned; ", things3
  pts4 = things4[0]
  fac4 = things4[1]
  puts "group4;", group4

  puts "made it this far"

rescue StandardError => e 
  puts "error last global outer try;", e
end