Triangulate triangles ?

cotty

I think the triangulation is not the same...

renderiza

Both of these are very useful so maybe add an option to choose between the two.

TIG

To do the former you need to first triangulate all faces, then find each triangle's center using the angles' bisectors' intersections...

renderiza

Not as easy as using the center of face.bounds.center is it.

If I find the best way to do it with code I'll let you know...Best of luck!

renderiza

I sure don't call the code below a success but its definitely interesting...


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

model.start_operation('csplit')
  faces.each do |face|
    vertices = face.vertices
    edges = face.edges
    bbox = face.bounds
    cpoint = bbox.center

   edges.each do |e|
      e1 = e.start.position
      e2 = e.end.position      

      x = (e2.x + e1.x) / 2
      y = (e2.y + e1.y) / 2 
      z = (e2.z + e1.z) / 2

      vertices.each do |vertex|
        p1 = [x, y, z]
        p2 = vertex
        line = ents.add_line p1,p2
      end
    end    
  end
  sel.clear
model.commit_operation

Note: I also find strange that new edges don't intersect with each othere making a new vertex...why is this?

renderiza

If the second time you apply script you do each face individually inside a group, then you get very pretty geometry.

JQL

Renderiza,

That's not success, that's brilliance!

I'll start designing tiles right away...

Thanks!

JQL

renderiza

Wish you success or better yet brilliance in your designs!

pilou

you make big progress and be near the success!

@unknownuser said:

Not as easy as using the center of face.bounds.center is it.

If I find the best way to do it with code I'll let you know.

Why not take the image of the first post as "pseudo code" ?

Calculate the point x,y,z crossing of 2 lines from 2 vertices to their middle opposite edge
(point can be also the calculate center of gravity of 3 points!
draw 3 lines from this point to the 3 vertices

Tig has finalized his "triangulate" method!
Medians stay in race!

Triangulate all faces by Tig (function was repeated for a sort of fractal system - only 3 triangles at start)

renderiza

Thanks guys! Will definitely study your suggestions.

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!