Ok I find the way, it works with local_bounds
model = Sketchup.active_model
sel = model.selection
bbox = Geom::BoundingBox.new
sel.each {|grp|
bbox=grp.local_bounds
get_entities(grp).find_all{|e| is_kind(e,"Face") }.each{|fc2|
pl2 = fc2.plane
if fc2.normal.parallel?( vec3d(0,0,1) ) and ( bbox.max.on_plane?(pl2))
fc2.layer = "K-Masque"
edges = fc2.edges
edges.each {|edg| edg.layer = "K-Masque"}
end
} }
I try to put the highest faces of a selection of groups in a specific layer. It works well if the group is on the origin, but can't find the way to make it work if the group is not on the origin.
model = Sketchup.active_model
sel = model.selection
bbox = Geom::BoundingBox.new
sel.each {|grp|
bbox.add(grp.bounds)
zgrp_max = bbox.max
get_entities(grp).find_all{|e| is_kind(e,"Face") }.each{|fc2|
pl2 = fc2.plane
if fc2.normal.parallel?( vec3d(0,0,1) ) and ( zgrp_max.on_plane?(pl2))
fc2.layer = "K-Masque"
edges = fc2.edges
edges.each {|edg| edg.layer = "K-Masque"}
end
} }
En fait le guide point sert à modifier l'ancien composant a cause d'un bug sur model.definitions.load(path) qui refuse de lire un composant dans le même répertoire qu'un composant enregistrer si celui ci n'est pas modifier.
Je suis donc obliger de mettre la partie guide point avant model.définitions.load(path).
cf : https://sketchucation.com/forums/viewtopic.php?f=180&t=60568
Bon c'est pas le top, mais ça marche:
J'ai placer la ligne problématique (ligne 72) entre deux start_operation.
Au bah oui pourquoi j'n y es pas penser 
when i use the "model start opération" the line -> new_definition = model.definitions.load(path) doesn't work at all and new_definition goes to the same definition of the old_definition.
but the reload() method works good if i don't use "model start opération" i got a new_definition and can remove the old one.
really strange.
On peut parler français remarque non?
Thanks for the answers, but still not working... 
I try to do a new plugin to save open and reload component inside a model and creat xref directory, it works well.
But i got trouble when I try to add "Model.start_operation" the plugin no longer works (refuse to load the new component). Any idea?
The attach file is functional for the trouble one you can erase the "#" on line 62 and line 83.
Thanks
I've done a Plugin with the core of section Cut Face withe some of new things:
A Layer organisation : Section is only done in few layer and keep the layer organisation
All face done with section Cut face'll go to the correct layer
A Automatic view creation : it create multiple view with specific layer and Style
The first view is for heavy line (Structure of Building)
The second is for middle line (2nd Oeuvre of Building)
The third view is for fine line (Object, doors, etc...) large scale
The fourth view is for fine line (Object, doors, etc...) small scale
The fifth view is for Hatch (with the layer color)
I've done some Scrapbook for layout to bring this view in a simple way...
The plugin : Vico-Section.rb
A Skp example with the layer organisation Orga.skp
You can access to the plugin with the right click on a Sketchup section (Plan is for top view / coupe is for section...)
You can update all the section with "Mise à jour des sections" in the extension menu...
Some exemple of drawing in layout : http://www.vico.lautre.net/portfolio/plan-sur-sketchup/
I've planed to do it more customized, but i need more time for that, and it 'll not be done soon 
Wow Faster API!
I work on a small plugin http://sketchucation.com/forums/viewtopic.php?f=80%26amp;t=66103
For Big Model SU2016 just can't do it (to much component definition...)
And SU2017 just do it in few seconds...
The 0.9.4 still working well on OS 10.11.6 SU2016
It was working with The 2016 on OS X
Pour cela il fallait juste copier l'ancienne installation sur /Bibliothèque/Application Support/Sketchup 2016/
(Pas dans User/Biblithéque/Application Support/Sketchup 2016/ mais à la racine du disque)
Cela ne marche pas pour Sketchup 2017
The old way still work for me (drop stuff in plugin folder)
Visualizer not working for me too
The extension manager is really better...
Same for me, I got this in the Ruby Consol :
Error: #<NoMethodError: undefined method length' for nil:NilClass> /Users/vico/Library/Application Support/SketchUp 2016/SketchUp/Plugins/tt_cc.rb:182:in get_transformation_difference'
/Users/vico/Library/Application Support/SketchUp 2016/SketchUp/Plugins/tt_cc.rb:117:in block in replace' /Users/vico/Library/Application Support/SketchUp 2016/SketchUp/Plugins/tt_cc.rb:107:in each'
/Users/vico/Library/Application Support/SketchUp 2016/SketchUp/Plugins/tt_cc.rb:107:in replace' /Users/vico/Library/Application Support/SketchUp 2016/SketchUp/Plugins/tt_cc.rb:29:in block in module:TT_CompComp'
SketchUp:1:in `call'
But with a simple model it works...
don't find why...
Hello this is one of my first plugin for Sketchup,
V1.2 add speed improvement for large model
Work very fast on SU2017 / in SU2016 can't do it for very big model ...
Acces:
Extension->VICO IFC
It does two things:
The next step 'll be to inspect the identical component and give them the same définition (like the tom-tom plugin : http://sketchucation.com/forums/viewtopic.php?p=264517#p264517)
I use my own Layer name, It's base on IFC format :
sorry i'm french
Building
A-BatA
A-BatB
...
Floor
B-N0
B-N1
...
Construction Parts
C-Murs
C-Dalle
C-Cloison
C-Men extérieure
...
tak2hata,
Thank for this plugin,
Do you think its possible to add a depth option like TIG punch hole tool?