How to draw a bubble in SketchUp

I need to draw this skylight using the Ruby API. I have no idea how to draw the bubble. Does anyone have a suggestion?


It looks like a shape that you could just import and scale.

That shape looks like it could be well represented with a bezier patch. If you use a 4x4 set of control points where you raise the top two ones and the generate a mesh using bezier interpolation you should get that shape.

You can poke at my Bezier Surface extension if you need some reference implementation:

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Here is a GIF demo:



The way my extension works I redraw everything from scratch when the user changes options, rather than importing a component. It’s a magnitude faster that way.

Nice! I’ll have a look. Thanks.

Ooh that looks complicated. It’ll take a bit for me to check it out.

The profile Looks like half a cos curve - maybe you can cheat and use the Face.followme method.

Don’t think that’ll work - since the curvature is longer from the corners than from the sides.

I’m working on creating my own mesh based off the bezier tool.

Also do to the fact that my skylight could be rectangular rather than square, for say a 2’ X 4’ skylight,

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I did end up using the follow me tool for my concave cupola roof.

Mr. Burkholder, I enjoy a good challenge. Here is my dashed up solution to drawing this complex shape.

Start by (programmatically) creating a grid one inch by one inch on a side. I have already made one for you in the attached grid.skp file. Then manipulate the grid with the grid_by_faces.rb code below. Lastly texture, scale and rotate! Enjoy




module DemoSpace
  model = Sketchup.active_model
  entities = model.active_entities
  model.start_operation('bubble', true)

  # grab the entities collection for your grid
  my_grid = {|e| e.is_a?(Sketchup::ComponentInstance) && = 'grid'}
  p 'name =' + my_grid[0].name
  ents = my_grid[0].definition.entities

  # cache the face outer_loops
  faces  = []
  ents.each { |f|
    next unless f.is_a?(Sketchup::Face)
    faces << {|v| v.position.to_a}
  puts 'number of faces = ' + faces.size.to_s

  #erase the original grid 
  #calculate new value for z for each vertex.
  # by iterating through the outer_loops, and loop vertices
  faces.each {|l|
    l.each {|v|
    v[2] = 0.3 * Math.sqrt(Math.sin(v[0] * Math::PI)) * Math.sqrt(Math.sin(v[1] * Math::PI)) if v[2] == 0.0
  # Add the calculated faces loops
  faces.each {|l| ents.add_face(l) } 

  # orient all of the faces in the up direction
  ents.each {|f| 
    next unless f.is_a?(Sketchup::Face)
    f.reverse! if f.normal.z < 0

grid.skp (147.6 KB)

grid_by_faces.rb (1.0 KB)


Nice! … and straight forward!

Yeah pretty good. I suggest using a PolygonMesh to create the geometry before adding anything to the model. That way you can create the finished mesh with smoothed lines in one go. Plus it’s faster.

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