Triangulate triangles ?

jolran

I Think you could use the circumcentre as well, for skewed triangles.. Maybe that's what Pilou is trying to Point out.

Here's some code I'm using for that. You might have to rewrite it to fit your needs..
I just ripped it out from a plugin I'm working on..

# Arguments need 3 point3D objects from triangle.
def points3_circumC(p1,p2,p3) #(Only 2 lines is actually needed for calculation)
	
	#Init Vectors for calculation.
	vec1  = p1.vector_to(p2) 
	vec2  = p1.vector_to(p3) 
	fakeZ = vec1.cross(vec2) #cross Plane...
	#midpoints
	mp1 = p1.offset(vec1, vec1.length/2)
	mp2 = p1.offset(vec2, vec2.length/2)
	#cross vectors..
	vec1 = vec1.cross(fakeZ)
	vec2 = vec2.cross(fakeZ)
	#lines
	line1 = [mp1, vec1]
	line2 = [mp2, vec2]
	return c = Geom.intersect_line_line(line1, line2) #point3D
end

edit: Ehh.. looks like TIG already bashed out a working plugin for this.

renderiza

It works!

Here is the code...


model = Sketchup.active_model
ents = model.active_entities
sel = model.selection
faces = sel.grep(Sketchup;;Face)

model.start_operation('csplit')
  faces.each do |face|
    v = face.vertices

    cx = v[0].position.x + v[1].position.x + v[2].position.x
    cy = v[0].position.y + v[1].position.y + v[2].position.y   
    cz = v[0].position.z + v[1].position.z + v[2].position.z 

    px = cx / 3
    py = cy / 3 
    pz = cz / 3 

    v.each do |vertex|
      p1 = [px, py, pz]
      p2 = vertex
      line = ents.add_line p1,p2
    end
  end
  sel.clear
model.commit_operation

Note: At the moment the above code works with triangles only.

For squares we can use the code bellow...


model = Sketchup.active_model
ents = model.active_entities
sel = model.selection
faces = sel.grep(Sketchup;;Face)

model.start_operation('csplit')
  faces.each do |face|
    v = face.vertices

    cx = v[0].position.x + v[1].position.x + v[2].position.x + v[3].position.x
    cy = v[0].position.y + v[1].position.y + v[2].position.y + v[3].position.y  
    cz = v[0].position.z + v[1].position.z + v[2].position.z + v[3].position.z 

    px = cx / 4
    py = cy / 4 
    pz = cz / 4 

    v.each do |vertex|
      p1 = [px, py, pz]
      p2 = vertex
      line = ents.add_line p1,p2
    end
  end
  sel.clear
model.commit_operation

renderiza

The following code will work on all geometry types like triangle, square, ect...

model = Sketchup.active_model
ents = model.active_entities
sel = model.selection
faces = sel.grep(Sketchup;;Face)
@addx = []
@addy = []
@addz = []

model.start_operation('csplit')
  faces.each do |face|
    @addx.clear
    @addy.clear
    @addz.clear

    v = face.vertices
    num = v.length

    v.each_with_index {|vert,i|
      @addx << " + v[#{i}].position.x"
      @addy << " + v[#{i}].position.y"
      @addz << " + v[#{i}].position.z"
    }

    ax = @addx * ","
    sumx = ax.delete ","

    ay = @addy * ","
    sumy = ay.delete ","

    az = @addz * ","
    sumz = az.delete ","

    cx = eval("#{sumx}")
    cy = eval("#{sumy}")
    cz = eval("#{sumz}")

    px = cx / num
    py = cy / num
    pz = cz / num

    v.each do |vertex|
      p1 = [px, py, pz]
      p2 = vertex
      line = ents.add_line p1,p2
    end

  end
  sel.clear
model.commit_operation

Note: To test code above you can copy & paste it to one of this ruby consoles...
http://renderizastudio.blogspot.com/2013/06/top-ruby-consoles-for-sketchup.html

renderiza

With the help of Dan Rathbun the code was improved! Because string manipulation in Ruby can be slow he figured a way to do it without strings.

Here is the new code...

  def csplit()
    #
    model = Sketchup.active_model
    ents = model.active_entities
    sel = model.selection
    faces = sel.grep(Sketchup;;Face)
    #
    model.start_operation('csplit')
      #
      faces.each do |face|
        #
        sum = Geom;;Point3d.new(0,0,0)
        #
        verts = face.vertices
        n = verts.size.to_f
        # use API Geom;;Point3d.+ instance method;
        verts.each {|v| sum += ORIGIN.vector_to(v.position) }
        #
        avg = Geom;;Point3d.new( sum.x/n, sum.y/n, sum.z/n )
        #
        verts.each {|v| ents.add_line( avg, v ) }
        #
      end # each face
      #
    model.commit_operation
    #
  rescue => e
    #
    puts "Error <#{e.class.name}; #{e.message} >"
    puts e.backtrace if $VERBOSE
    #
    model.abort_operation
    #
  else # when no errors;
    #
    sel.clear
    #
  end # csplit()

  csplit()

If you have the time make sure to thank Dan...Cheers!