[Plugin] FaceSplit v1.0.3

cotty

Discussion which leads to this nice plugin...

Nice! Thank you.

renderiza

Thank you for giving a link to the Discussion that started it all. Also here is another that played a big part in optimizing the code.

Apart from dividing the face like in the second row of the image, was thinking to add additional options like the ones below that. The trick here is to provide an easy to understand user interface where you can change the options.

mitcorb

Something like: split by angles to centroid, split by medians to centroid, split by angles to medians, split by angles, medians through centroid?
Or, split by bisect angles, bisect edges, ??

renderiza

@mitcorb said:

Something like: split by angles to centroid, split by medians to centroid, split by angles to medians, split by angles, medians through centroid?

Correct!

@mitcorb said:

Or, split by bisect angles, bisect edges, ??

Was not thinking of this option but, if I am not mistaken TIG's TriangulateAllFaces is accomplished this way.

glro

The purpose of such a plugin may be purely graphical, and all the options mentioned are interesting

There is another purpose possible
http://www.spatial.com/products/3d-mesh

"3D Mesh provides automatic mesh generation for curves, surfaces (triangle and quadrilateral) and volumes (tetrahedral)"

sketchup is not a real 3d software, since a volume is only a space closed by surfaces

Would it be possible to write a plugin that would do something similar to what 3d mesh does, by drawing lines on the surfaces and between the surfaces

3d mesh may follow different patterns
http://www.ansys.stuba.sk/html/guide_55/g-mod/GMOD7.htm

This mesh could be exported to a structural analysis software

Might be related to Voxelize
http://sketchucation.com/forums/viewtopic.php?t=36063

a lot of work, though...

iichiversii

excellent, ill be using that
Thanks for sharing

tomot

very nice!
I was thinking of an added option also: We now have split from vertex, can we add split from midpoint?

renderiza

Warning!
The examples shown below are not features the current version support. These are ideas for possible future updates so please don't be confused by it.

From vertices to centeroid (Current function of plugin)

Currently the plugin has no problem when dealing with multiple faces because the existing edges are no sliced. We only add new vertex in center of geometry and reuse the existing face vertices after that.

From medians to centeroid

In this case we do split the existing edges in half and that cause effect we see in the 3rd row of the image. Each face will exponentially increase the number of edges in which the script will divide causing different results each time.

The example in the 2nd row of the image was able to maintain the same amount of edges per face because each color represent a group. Notice none of the same color groups can touch each other.

Conclusion
Will have to figure out a way to reproduce the results in the 2nd row of image without having to make multiple groups. Not sure how at the moment but maybe if I open this to discussion in the development forum it can get solved quickly.

When I saw the results on row number 3 of image I sort of like what I saw. Maybe this effect is what someone might want who knows.

glro: That would be ideal for the plugin to reach to that level but first I need to figure out simple stuff like the ones mentioned above. Thanks for your input really appreciate it!

iichiversii: Hey long time no see!!! Glad you found a use for it.

tomot: Yes above I tried demonstrated some of the issues to solve before adding the feature of splitting from medians to centroid.

TIG

No need to group ?
Collect all of the faces.
Then collect points for each of the faces - i.e. the 'center' point and the all of the perimeter points needed.
Iterate the points collection - get the 'center' point, then add the new edges from the other points...

### pseudo-code...
faces=[face1, face2, etc]
points=[[face1_points_array], [face2_points_array], etc]
### NOW add edges from each fixed set of points
points.each{|pts|
  cpt=pts.shift ### gets/removes 1st point
  pts.each{|pt| ents.add_line(cpt, pt) }
}

renderiza

Look what happens if you test the code above with object similar to the one in image below. If the face has a hole in the middle and is not triangulated or quadrangular like in the 2nd row the result can be messy.

The second row show much better result because the first object had quad face before applying script.

Hope this helps.

renderiza

Thank you TIG will try that ASAP!!!

...TIG's suggestion works! Here is a code sample that you can copy & paste for testing...

The only function the code does is to split faces from medians to centroid.

def csplit()
			
model = Sketchup.active_model
ents = model.active_entities
sel = model.selection
faces = sel.grep(Sketchup;;Face)
edges = []
avg = []
cl = []

model.start_operation('csplit')

	faces.each do |face|
		edges << face.edges
		###########
		# Medians #
		###########
		lines = face.edges
		lines.each {|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
		cl << Geom;;Point3d.new( x, y, z )
		}
		############
		# Centroid #
		############
		sum = Geom;;Point3d.new(0,0,0)
		verts = face.vertices
		n = verts.size.to_f
		verts.each {|v| sum += ORIGIN.vector_to(v.position) }
		avg << Geom;;Point3d.new( sum.x/n, sum.y/n, sum.z/n ) #/
	end # each face

	############################
	# From Centroid to Medians #
	############################
	faces.each do |face|
		centroid = avg.shift			
		edges.shift.each {|e| 
			lc = cl.shift
			ents.add_line( centroid, lc ) 
		}
	end

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()

#######
# Run #
#######
csplit()

Always welcome suggestion to make code better...cheers!

TIG

I was about to tell you of the issue with faces with holes or L shapes having a centroid 'off-face', but you have displayed it already...
Here is the 'fix'...
As you iterate each face check
face.classify point(cpt)
If it is not on the face, on a face-edge or on a face-vertex then do this:
tr=Geom::Transformation.new() es=ents.intersect_with(false, tr, ents, tr, true, ents.to_a)
You could reduce the intersected array to say face.edges provided you have a reference to the face ?
Then if some edges collected into 'es' remain 'unfaced' use this to erase them? :
es.grep(Sketchup::Edge).each{|e|e.erase! unless e.faces[0]}

pilou

Bravo!
Some testings in view and some track the bugs!

Ps you are very friendly to have put my name but take attention that I have not made any code just a little moment of inspiration (given by a French guy anar!

anar

@unknownuser said:

Bravo!
Some testings in view and some track the bugs!

Ps you are very friendly to have put my name but take attention that I have not made any code just a little moment of inspiration (given by a French guy anar!

Thanks Pilou for mentioning that I started that discussion with you here : http://www.polyloop.net/showthread.php/9854-Topmod-De-la-maille-topologique%21/page7#133

And thanks also because without you that plugin would have never been made !

Anar
http://www.reppersdelight.spacymen.com

glro

@renderiza said:

Look what happens if you test the code above with object similar to the one in image below. If the face has a hole in the middle and is not triangulated or quadrangular like in the 2nd row the result can be messy.

The second row show much better result because the first object had quad face before applying script.

Hope this helps.

i thought it was only for surfaces, but i see that it works on volumes also...

would it be possible to split the volume following the liness making like a 3d puzzle?

this would mean adding surfaces following the lines to make independant volumes

like "voxelize.rb", but not only cubes

pilou

Seems working fine

pilou

And all medians are present!
I don't want imagine the possibilities in 3D!

renderiza

TIG: Thank you TIG will test that out effective immediately!

Pilou & Anar: People that bring ideas to the table deserve recognition as well.

glro: That would be very cool indeed! I think there is a plugin that does something like this but don't remember it just now. If I find it will let you know.

Pilou: Very cool!

Pixero

Hi!

May I suggest an addition.
For people working in 3ds Max a imported SketchUp model is sometimes hard to work with because it doesn't consist of evenly sized quad faces. I have this idea to be able to split a face with inner loops like windows by projecting lines in the direction of the edges to the outer loop.
See this quick sketch.

glro

@renderiza said:

..
[b]glro: That would be very cool indeed! I think there is a plugin that does something like this but don't remember it just now. If I find it will let you know.

:

Maybe you think also to voxelize.rb
http://sketchucation.com/forums/viewtopic.php?t=36063

but voxelize makes cubes only; it would be funny to split the volume in exact sub-volumes, and try to build the whole volume back again, using sketchup

i have a 3d connexion mouse, and there is a game like this, to learn how to use it

and in addition, splitting a volume in sub-volumes is equivalent to building a 3d mesh, for structural analysis...