Group.volume

morci429

Guys did anyone try using group.volume function?? i've been trying to use it but it doesn't seem to work. any body came across the same thing before??

Dan Rathbun

@unknownuser said:

](http://code.google.com/apis/sketchup/docs/ourdoc/group.html#volume)":3osf11lz]

Sketchup 8.0+

The volume method is used to compute the volume of this group if and only if this group is manifold.

... If the group represents a manifold volume, volume will be a positive value. If volume is negative, the group is not manifold.

See Also: Group.manifold?

Dan Rathbun

Mike, are you using Free or Pro edition ?

Can you provide an example of when it "doesn't work" ?

Didier Bur

Hi,

If you're in trouble with group.volume, try this: (assumed g parameter is a group entity)

def vol(g)
	v=0.0
	for face in g.entities
		next unless face.kind_of? Sketchup;;Face
		v +=(2*face.area*face.vertices[rand(2).to_i].position.to_a.dot(face.normal))/6
	end
	# if needed, convert cubic Inches to m3
	return (v * 0.000016387064)
end

morci429

Hi Didier, Great code thank u very much it did the job for me but its always worth to learn another way so Dan here's what i was trying to do with group.volume


pt = []
pt[0] = [0,0,0];pt[1] = [100,0,0];pt[2] = [100,100,0];pt[3] = [0,100,0]
face = Sketchup.active_model.entities.add_face pt
face.pushpull -100

then i had to find out how many entities i had in the model and which of them is faces so i can add them to the group using selection.clear and selection.add

and then i add all the faces to a group and i made a few copies of it.
and i tried to use the function but it never worked.
could you demonstrate a good practice of the function?
thanks you

TIG

Why not add the face directly into the group in the first place?

model=Sketchup.active_model
group=model.active_entities.add_group()
face=group.entities.add_face(pt)
face.pushpull(-100)
faces=[]
group.entities.each{|e|faces << e if e.class==Sketchup;;Face}

now faces is an array of all of the new faces inside group ?
You can use new_group=group.copy etc...
Then

new_faces=[]
new_group.entities.each{|e|new_faces << e if e.class==Sketchup;;Face}

etc etc...

morci429

that is certainly a better way thank you.
but still group.volume still not working.
did you use it before? what would be the way to use it?
thanks

TIG

The group.volume in v8 [ http://code.google.com/apis/sketchup/docs/ourdoc/group.html#volume ] and Didier's way otherwise should both work... for 'manifold' / 'solid' forms...
What is the output/error in the Ruby Console ?

thomthom

@morci429 said:

but still group.volume still not working.

Exactly what isn't working?
Unexpected result?
Errors?

morci429

Didier's way is working with no proplems.
and this is the error message when i try to use group.volume
group.volume
Error: #<NoMethodError: (eval):41: undefined method `volume' for #Sketchup::Group:0x4d28ba0>
(eval):41

morci429

i think i know where the problem is.. it only works in SketchUp 8. i just tried it
really sorry about that.
i was using 7 before that