How to change transformation origin from Global to local (set origin)

Developers Ruby API
1

Hi all,

I am a bit stumped and any help would be appreciated.

I have a group which I want to copy/transform multiple times to various distances on the Z axis. The first three groups move only, the remaining groups move and rotate. (code below)

  1. How do I change the rotation origin from global to a set position? Global = [0,0,0] new origin = [0,0,2327.mm]

  2. Does being in a loop have an impact on changing the origin?

transformation example
transformation example1174×615 52.8 KB 

    mod = Sketchup.active_model 
    ent = mod.active_entities 
    sel = mod.selection 
    
    # THE Z DIST FOR EACH GROUP FROM GLOBAL ORGIN [0,0,0]
    z_dist = [0.mm, 50.mm, 147.mm, 
    2327.mm, 2339.mm, 2364.mm, 
    2402.mm, 2499.mm, 2500.mm]
    
    # THE NUMBER OF GROUPS
    num_copies = levels.length-1

    # VERTICES FROM SELECTION 
    pts_arr= sel.grep(Sketchup::Face) {|f| f.vertices.map{|v| v.position } }

    # VERTICES TO GROUP 
    group = ent.add_group(sel.to_a)
    ent = group.entities
    pts = ent.add_face (pts_arr)

    # LOOP THE NUMBER OF GROUPS 
    for i in 1..num_copies
    
      # Z DISTANCE NUM IS = TO NUM OF GROUPS
      zed = z_dist[i]
      orgin = [0,0,0]
      
      # IF Z DIST > 2 THE ANGLE = 5 DEGREES ELSE ANGLE = 0 
      if i >2 then d = -5 
      # orgin = [0,0,2327] ???????????? 
      # HOW TO CHNAGE THE TRANSFORMATION ORIGIN 
          else
            d = 0
      end
    
     z_pos = Geom::Vector3d.new(0,0,zed.to_i)
     tr_rot = Geom::Transformation.rotation(orgin, X_AXIS, d.degrees)
     tr_mov = Geom::Transformation.translation(z_pos)

      transform = tr_rot * tr_mov

      t = group.transformation
      t = transform
      new_group = group.parent.entities.add_instance(group.entities.parent,t)
      new_group.name = "group#{i+1}"
  
  end
2

Here is an old example showing the repeated use of a rotational transformation.

1 Like
3

This looks helpful. Many thanks