Interrogating each group to find Cylinders & Cubes

[nkclarke]

I'm new to script writing but I'm trying to write a Ruby script to complete a task I've been given at work. I have a skp file containing only separate groups (several hundred). Each group consists of EITHER a CYLINDER or a CUBOID. I'm trying to come up with a script that examines each group in turn and can judge whether the shape is a cylinder or a cuboid. If the shape turns out to be a cylinder, I need to extract the co-ordinates of the face centre, the diameter of the circle and the length of the cylinder. If the group meets the criteria of a cuboid, I need the co-ords of the lower corner/vertex and the dimensions of the cuboid.

Also, I need to be able to export the above information into a text file.

Any tips or help would be gratefully appreciated. Or, a view on the achievability of what I'm trying to do would also be useful.

Thanks

[TIG]

@nkclarke said:

I'm new to script writing but I'm trying to write a Ruby script to complete a task I've been given at work. I have a skp file containing only separate groups (several hundred). Each group consists of EITHER a CYLINDER or a CUBOID. I'm trying to come up with a script that examines each group in turn and can judge whether the shape is a cylinder or a cuboid. If the shape turns out to be a cylinder, I need to extract the co-ordinates of the face centre, the diameter of the circle and the length of the cylinder. If the group meets the criteria of a cuboid, I need the co-ords of the lower corner/vertex and the dimensions of the cuboid.
Also, I need to be able to export the above information into a text file.
Any tips or help would be gratefully appreciated. Or, a view on the achievability of what I'm trying to do would also be useful.
Thanks

If you have groups then you can of course give them names like group.name='cuboid' and group.name='cylinder' - then NO tests are needed just compare the names !!!

If that simple trick won't do...
To see if a 'face' belongs to a cuboid test it for number of edges and connected faces...

face=nil
group.entities.each{|e|
  if e.class==Sketchup;;Face
    face=e
    break
  end
}
not_cuboid=false
not_cuboid=true if face.edges.length!=4
faces=[]; face.all_connected.each{|e|faces << e if e.class==Sketchup;;Face}
not_cuboid=true if faces.length!=6
faces.each{|f|
  if f.edges.length!=4
    not_cuboid=true
    break
  end
}

'face' is a cuboid 'if not not_cuboid'
This doesn't trap a cylinder made with 4 sided circles which would look 'cuboid' too...
If the cylinder is truly made from a 'circle' then you can test further for 'curve' and 'smooth' edges

faces.each{|f|
  f.edges.each{|e|
    if e.curve and e.curve.class==Sketchup;;ArcCurve
    end
    if e.smooth?
      not_cuboid=true
      break 
    end
  }
  break if not_cuboid
}

It also doesn't trap for non-right-angled corner cuboids... to check for that

faces.each{|f|
  verts=f.vertices
  vertsp=verts+verts[0]+verts[1]
  (verts.length).each{|i|
    veca=vertsp[i+1].vector_to(vertsp[i])
    vecb=vertsp[i+1].vector_to(vertsp[i+2])
    ang=veca.angle_between(vecb)
    if ang!=90.degrees
      not_cuboid=true
      break
    end
  }
}

...

If it's a cuboid then get bb=group.bounds and then
x=bb.min.x y=bb.min.y z=bb.min.z
If it's a cylinder find the 'circle' face

circle=nil
len=nil
group.entities.each{|e|
  if e.class==Sketchup;;Edge
    if e.curve and e.curve.class==ArcCurve
      circle=e
      len=e.length
      break
    end
  end
}
center=circle.center
diameter=circle.radius*2
height=nil
group.entities.each{|e|
  if e.class==Sketchup;;Edge
    if not e.curve
      height=e
      break
    end
  end
}

You now have center, diameter and height for the cylinder...

[nkclarke]

Thank you so much for that. You went to a lot of trouble for me and I appreciate it. I think it'll take me some time to get my head around it but for me it's a good introduction to Ruby.

[nkclarke]

Once I've been able to extract all of the data I need during my interrogation of all the groups, is it possible to export these variables into a separate text file? Or does the Ruby environment within SketchUp prefer the user to stay within SketchUp?

[TIG]

It's easy enough to export data to a file.
Find ComponentReporter++.rb for an example...
Export and Import are relatively straightforward, it how you manipulate the data before/afterwards that's more tricky...

[peterjohnson84]

I am also working on this problem and though I follow the logic behind the code you wrote - I am struggling to implement it.

How do you get sketchup to recognise the group.(...) method? i.e. stop it returning the error:

undefined local variable or method `group' for JF::WebConsole:Module

when I type:

    face=nil
    group.entities.each{|e|
      if e.class==Sketchup;;Face
        face=e
        break
      end
    }
    not_cuboid=false
    not_cuboid=true if face.edges.length!=4
    faces=[]; face.all_connected.each{|e|faces << e if e.class==Sketchup;;Face}
    not_cuboid=true if faces.length!=6
    faces.each{|f|
      if f.edges.length!=4
        not_cuboid=true
        break
      end
    }

Its as if sketchup doesn't know what group I'm referring to - doesn't know what 'group' even is. After searching I have noticed some talk about 'active_entities' and suspect the answer may be invlved with this somehow.

Apologies if this sounds like nonsense - I think I'm missing something big, but can't work out what it is.

Cheers, Pete

[thomthom]

@peterjohnson84 said:

Its as if sketchup doesn't know what group I'm referring to

Because it doesn't. group is just another variable - you need to make a it reference the group you want.

For instance, if you want group to reference the selected object:
group = Sketchup.active_model.selection[0]

[peterjohnson84]

That's the badger! Though as is the way with these things, it seems so simple once I know the solution.

Thankyou very much anyway...that has helped me a great deal.