Triangulate triangles ?

pilou

Alas I have deserted the Ruby language for a while!

If you can make a little plugin that will be wonderful

renderiza

Here is an example code for achieving what you want Pilou...


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

faces.each do |face|
  vertices = face.vertices
  bbox = face.bounds
  cpoint = bbox.center

  vertices.each do |vertex|
    p1 = cpoint
    p2 = vertex
    line = ents.add_line p1,p2 
   end
end

Note: Some very pretty geometry start appearing when you keep splitting!

renderiza

I will do that!

TIG

Beat me to it
You might want to change the
faces = ents.grep(Sketchup::Face)
to
faces = **sel**.grep(Sketchup::Face)
So then the user changes only selected faces ?
OR perhaps
faces = sel.grep(Sketchup::Face) faces = ents.grep(Sketchup::Face) **unless faces[0]**
so it works on a selection OR everything if there is no selection...

Also you want to make it undoable, so add
**model.start_operation('subtri')** faces.each... ...end **model.commit_operation**

renderiza

Hahaha!

TIG I would be very happy if you modify your existing plugin to add Pilou is feature request.

I am interested in making this for learning and I have some additional ideas I want to explore. I consider you my mentor TIG and there will never be competition between you and me I promise!

By the way thanks for the suggestion!

Here is updated 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|
    vertices = face.vertices
    bbox = face.bounds
    cpoint = bbox.center

    vertices.each do |vertex|
      p1 = cpoint
      p2 = vertex
      line = ents.add_line p1,p2
    end
  end
  sel.clear
model.commit_operation

TIG

OK
I'll make a simple script and publish it shortly...

renderiza

Thank you TIG!

anar

Thanks Pilou !
You convinced TIG...
And Thanks TIG, I think it's a must have !

TIG

Try this http://sketchucation.com/forums/viewtopic.php?p=495430#p495430
TriangulateAllFaces...

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.