Ruby script to output outer face loop?

emptyvessel

I guess I am confused about straight lines.
From the API documentation I was under the impression that an Edge could be
A line, curve, or arccurve.

How do I determine which is which in an if statement.
Won't All three be true for "if edge.is_a? Sketchup::Edge"?

tt_su

An Edge can be part of an ArcCurve or Curve.

Use Edge.curve to check this, it will return the curve instance if it is and nil if it't not.
http://www.sketchup.com/intl/en/developer/docs/ourdoc/edge.php#curve

slbaumgartner

@tt_su said:

An Edge can be part of an ArcCurve or Curve.

Use Edge.curve to check this, it will return the curve instance if it is and nil if it't not.
http://www.sketchup.com/intl/en/developer/docs/ourdoc/edge.php#curve

The tricky part for Ruby developers is that ArcCurve and Curve do not appear in the Entities collection. That is, you can't detect that they exist by scanning the Entities. You have to test Edges to find them.

Steve

tt_su

True that - they are meta-entities.

emptyvessel

Okay I have a test script that iterates over the outer loop of a simple rectangle with
a radius at each corner. What I cannot figure out is how to return just the four lines and four arcs.

What I get with the following code is four lines and a hit for every facet in each arc.

What am I doing wrong?


require 'sketchup'
 
model = Sketchup.active_model
face = model.selection[0]

if (face) 
  loop = face.outer_loop
  edgeuses = loop.edgeuses 
  
  edgeuses.each do|edgeuse|

    edge = edgeuse.edge
    curve = edge.curve
    if (curve)
      if curve.is_a? Sketchup;;ArcCurve
        UI.messagebox "Edge is an Arc Curve"
      else
        UI.messagebox "Edge is a Curve"
      end
    else
        UI.messagebox "Edge is a Line"
    end
  
  end  # end edgeuses each
  
end

slbaumgartner

You find the same curve again and again for each Edge associated with it. When you find a curve, you need to use its edges method to get the other Edges in the same Curve and remove them from further consideration. For instance,


require 'sketchup'
 
model = Sketchup.active_model
face = model.selection[0]
used_edges = []
if (face) 
  loop = face.outer_loop
  edgeuses = loop.edgeuses 
  
  edgeuses.each do|edgeuse|
    edge = edgeuse.edge
    next if used_edges.index edge 
    curve = edge.curve
    if (curve)
      used_edges = used_edges | curve.edges
      if curve.is_a? Sketchup;;ArcCurve
        UI.messagebox "Edge is an Arc Curve"
      else
        UI.messagebox "Edge is a Curve"
      end
    else
        UI.messagebox "Edge is a Line"
    end
  
  end  # end edgeuses each
  
end

emptyvessel

I think you gentlemen may be giving me too much credit for my knowledge of ruby.
I am a rank beginner and do not get everything your are saying or showing in your snippets.

slbaumgartner: your code still displays a arccurve message for all facets of the arc.
How is "next if used_edges.index edge" suppose to remove edges from consideration?

tt_su: Your code fails to run at all. "EdgeUses not found"
Would you be so kind as to explain how each line of your snippet works.

Regards,

emptyvessel

Okay, Looked up the 'Uniq' method Now I am even more puzzled.
The following code is a modified version of tt_su's.
Uniq appears to be returning the wrong number of array elements.


model = Sketchup.active_model
face = model.selection[0]

if face
  count = 0
  edges_and_curves = []
  edges_filtered = []
  
  loop = face.outer_loop
  edgeuses = loop.edgeuses  

  edgeuses.each do|edgeuse|
    count += 1
    edge = edgeuse.edge
    edges_and_curves << edge.curve || edge
  end
  
  edges_filtered = edges_and_curves.uniq

  UI.messagebox(edges_filtered.length)  # Reports 5 Should be 8
  UI.messagebox(count) # Correctly reports 52. (4 sides and 4 arcs * 12 facets)  Correct.
end

slbaumgartner

@emptyvessel said:

I think you gentlemen may be giving me too much credit for my knowledge of ruby.
I am a rank beginner and do not get everything your are saying or showing in your snippets.

slbaumgartner: your code still displays a arccurve message for all facets of the arc.
How is "next if used_edges.index edge" suppose to remove edges from consideration?

tt_su: Your code fails to run at all. "EdgeUses not found"
Would you be so kind as to explain how each line of your snippet works.

Regards,

Hmm. I edited my post after I found errors (typed too fast) - did you try the latest version? I drew a rectangle, changed all the corners to arcs, and ran this and it report four Edges and four ArcCurves... When it completes it dumps a whole Array of stuff on the Console, but that is just because Ruby always returns the last thing it evaluated and I didn't bother to stop it.

If you have a specific example skp, please post it and I'll try to see what went astray.

Also, it looks to me like TT also typed in haste. I don't think his code is right...for instance edgeuses is undefined!

Steve

tt_su

<span class="syntaxdefault"><br />model </span><span class="syntaxkeyword">=</span><span class="syntaxdefault"> Sketchup</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">active_model<br />face </span><span class="syntaxkeyword">=</span><span class="syntaxdefault"> model</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">selection</span><span class="syntaxkeyword">[</span><span class="syntaxdefault">0</span><span class="syntaxkeyword">]<br /><br /></span><span class="syntaxdefault">if face<br />  edges_and_curves </span><span class="syntaxkeyword">=</span><span class="syntaxdefault"> </span><span class="syntaxkeyword">[]<br /></span><span class="syntaxdefault">  face</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">outer_loop</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">edgeuses</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">each </span><span class="syntaxkeyword">{</span><span class="syntaxdefault"> </span><span class="syntaxkeyword">|</span><span class="syntaxdefault">edgeuse</span><span class="syntaxkeyword">|<br /></span><span class="syntaxdefault">    edge </span><span class="syntaxkeyword">=</span><span class="syntaxdefault"> edgeuse</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">edge<br />    edges_and_curves </span><span class="syntaxkeyword"><<</span><span class="syntaxdefault"> edge</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">curve </span><span class="syntaxkeyword">||</span><span class="syntaxdefault"> edge<br />  </span><span class="syntaxkeyword">}<br /></span><span class="syntaxdefault">  </span><span class="syntaxcomment"># Because we will have added the Curve entities for each edge segment.<br /></span><span class="syntaxdefault">  edges_and_curves</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">uniq</span><span class="syntaxkeyword">!<br /></span><span class="syntaxdefault">end<br /></span>

tt_su

In deed - I typed in a hurry and made a mess out of it. I made changes in a hurry now as well, but I still haven't checked it properly. Sorry. I'll get back to this next week. Now I need to get to bed as I'm catching a plane early in the morning.

emptyvessel

Okay I worked on this this weekend and I am ALMOST getting the output I want...


'VB.NET Code output
gp.AddLine(0.000,10.000,0.000,2.000)
gp.AddArc(0.000,8.000,4.000,4.000,0.000,90.000)
gp.AddLine(10.000,12.000,2.000,12.000)
gp.AddArc(8.000,8.000,4.000,4.000,0.000,90.000)
gp.AddLine(12.000,2.000,12.000,10.000)
gp.AddArc(8.000,-0.000,4.000,4.000,0.000,90.000)
gp.AddLine(2.000,0.000,10.000,-0.000)
gp.AddArc(0.000,0.000,4.000,4.000,0.000,90.000)

The start and end arc angles all appear to be 0 and 90.
The x,y center point is different for each so I know I am getting each arc in the loop.

How does this work?

My latest conversion code.


require 'sketchup'

# Task; Convert sketchup face outer loop to VB.NET graphicpath code

def ConvertToDotNetLine(edge)
  # Convert to VB.NET code graphicpath line definition
  startpt = edge.start.position
  endpt = edge.end.position
    
  s = "gp.AddLine("
  s += "%.3f" % startpt.x.to_f + ","
  s += "%.3f" % startpt.y.to_f + ","
  s += "%.3f" % endpt.x.to_f + ","
  s += "%.3f" % endpt.y.to_f + ")\n" 
  return s
end

def ConvertToDotNetArc(arc)
  # Convert to VB.NET code graphicpath arc definition

  x = arc.center[0]-arc.radius # Left of arc circle's bounding box.
  y = arc.center[1]-arc.radius # Top  of arc circle's bounding box.
  wt = arc.radius * 2          # width of arc circle's bounding box.
  ht = wt                      # height of arc circle's bounding box.
  startang = arc.start_angle
  endang = arc.end_angle

  s = "gp.AddArc("
  s += "%.3f" % x.to_f + ","
  s += "%.3f" % y.to_f + ","
  s += "%.3f" % wt.to_f + ","
  s += "%.3f" % ht.to_f + ","
  s += "%.3f" % startang.radians + ","
  s += "%.3f" % endang.radians + ")\n"  
  return s
end

model = Sketchup.active_model
face = model.selection[0] 

if (face) 
  sout = ""
  used_edges = []
  loop = face.outer_loop
  edgeuses = loop.edgeuses 

  edgeuses.each do|edgeuse|
    edge = edgeuse.edge
    next if used_edges.index edge 
    curve = edge.curve
    if (curve)
      used_edges = used_edges | curve.edges
      if curve.is_a? Sketchup;;ArcCurve        
        sout += ConvertToDotNetArc(curve)
        # UI.messagebox "Edge is an Arc Curve"        
      else
        UI.messagebox "Edge is a Curve"
      end
    else
        sout += ConvertToDotNetLine(edge)
        # UI.messagebox "Edge is a Line"
    end    
  end  # end edgeuses each 
  
  f = File.open("C;\\aaapath.txt", "w")
  f.write(sout)  
  f.close  
  
  UI.messagebox(sout)
end

emptyvessel

Discovered the Angle_Between() method and I am now calculating the start angle.

Things are looking better...
Except now I see that an outer loop in Sketchup is not a true path.
Endpoints of edges are not necessarily coincident with the start point of the next edge.

Is there some method or setting that will force this situation?
Otherwise I am looking at recreating every edge and curve in the correct order.

This is turning into a much bigger project than I had originally hoped.

tt_su

Use the Loop and EdgeUse objects that a face will give you:
http://www.sketchup.com/intl/en/developer/docs/ourdoc/face.php#loops

That will let you traverse the edges and vertices of a face in correct order.

emptyvessel

Thank you Thomas for the reply.

So to verify you are saying that the Loops object returns edges in order, but the outer_loop does not. Correct?

[Edit]
Nope doesn't seem to matter. It is still creating lines flipped around.
(see attachment)
[/Edit]

Output from my ruby. Drawn in Top view.

tt_su

face.outer_loop returns a Loop object. Loop object will return vertices in order and it will return EdgeUse objects in order.

If you have an Edge and want to figure out it's direction in relationship with a face you must use edge.reversed_in?(face).