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    [solved] taking points at intervals from a line

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    • TIGT Offline
      TIG Moderator
      last edited by

      Let's call them p0 and p1
      The distance between them...
      dis=p0.distance(p1)
      Let's assume we want to find a set of points at 1/n steps
      step=dis/n
      Then process and increment
      vec=p0.vector_to(p1) pts=[p0] p=p0.clone (n-1).times{ pt=p.offset(vec, step) pts << pt p=pt.clone } pts << p1
      You now have an array 'pts' of all points including the start and end ones and all intermediate ones as required...

      TIG

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      • K Offline
        kdasilva
        last edited by

        @dan rathbun said:

        @kdasilva said:

        how can I get 10 Point3d's evenly spread out along this line that I can use as anchors for my text....

        Divide the line by 9

        <span class="syntaxdefault">arr</span><span class="syntaxkeyword">=[]<br /></span><span class="syntaxcomment"># load array with the txt values in order<br /></span><span class="syntaxdefault">pt  </span><span class="syntaxkeyword">=</span><span class="syntaxdefault"> edge</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">start</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">position<br />vec </span><span class="syntaxkeyword">=</span><span class="syntaxdefault"> edge</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">line<br />num </span><span class="syntaxkeyword">=</span><span class="syntaxdefault"> dict</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">size</span><span class="syntaxkeyword">-</span><span class="syntaxdefault">1<br />seg </span><span class="syntaxkeyword">=</span><span class="syntaxdefault"> vec</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">length </span><span class="syntaxkeyword">/</span><span class="syntaxdefault"> num<br />vec</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">length </span><span class="syntaxkeyword">=</span><span class="syntaxdefault"> seg<br />arr</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">each_with_index </span><span class="syntaxkeyword">{|</span><span class="syntaxdefault">e</span><span class="syntaxkeyword">,</span><span class="syntaxdefault">i</span><span class="syntaxkeyword">|<br /></span><span class="syntaxdefault">  pt</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">offset</span><span class="syntaxkeyword">!(</span><span class="syntaxdefault">vec</span><span class="syntaxkeyword">)</span><span class="syntaxdefault"> if i</span><span class="syntaxkeyword">></span><span class="syntaxdefault">0<br />  entities</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">add_text</span><span class="syntaxkeyword">(</span><span class="syntaxdefault"> arr</span><span class="syntaxkeyword">[</span><span class="syntaxdefault">i</span><span class="syntaxkeyword">],</span><span class="syntaxdefault"> pt </span><span class="syntaxkeyword">)<br />}</span><span class="syntaxdefault"> </span>
        

        I am trying my hardest to get this to work, unfortunately I have been unsuccessful thus far.....i put in:

        def draw_vision_field
          vision_field = ["test1", "test2", "test3", "test4", "test5"]
          pt = $line.start.position
          puts pt
          vec = $line.line
          puts vec
          num = vision_field.size - 1
          puts num
          seg = vec.length / num
          puts seg
          vec.length = seg
          vision_field.each_with_index {|e,i|
            pt.offset!(vec) if i > 0
            $ents.add_text( vision_field[i], pt )
          } 
        end
        

        I just put a test array to print for now. I added the puts in order to try and debug, I am getting this error message regarding the length= function on a vector...also the last number before the word error (the vec.length /num ), weirdly enough is always 0, i removed the /num and it always prints as 2, no matter how long the line is i make)

        
        (-350507.397831", 21906.712364", 0")
        (-350507.397831", 21906.712364", 0")
        (0.131501105216966, 0.991316023943281, 0.0)
        4
        0
        Error; #<NoMethodError; undefined method `length=' for [Point3d(-350507, 21906.7, 0), Vector3d(0.131501, 0.991316, 0)];Array>
        (eval);70;in `draw_vision_field'
        (eval);55;in `draw_the_line'
        (eval);28;in `onLButtonDown'
        (eval);73
        

        also... where does the method each_with_index come from? I can't find it in the sketchup api, and I could only find each_index in the ruby-doc http://www.ruby-doc.org/core/classes/Array.html#M000232

        thanks for the help

        korbin

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        • K Offline
          kyyu
          last edited by

          @kdasilva said:

          <snip>
          i removed the /num and it always prints as 2, no matter how long the line is i make)
          <snip>

          You don't want to use a line. A line would have infinite length. Anyways, it's just seen as an array ( type "edge.line.class"). So the length of that array is always 2 elements in that array, which defines a line.

          You want to use the vector from the edge:

          pt1 = edge.start.position
          pt2 = edge.end.position
          vec = Geom;;Vector3d.new [(pt2.x-pt1.x), (pt2.y-pt1.y), (pt2.z-pt1.z)]
          edge_length = vec.length
          

          @kdasilva said:

          <snip>
          also... where does the method each_with_index come from? I can't find it in the sketchup api, and I could only find each_index in the ruby-doc http://www.ruby-doc.org/core/classes/Array.html#M000232

          thanks for the help

          korbin

          The sketchup api just documents, extra ruby Modules/Classes/methods for sketchup. It doesn't document the entire ruby language.

          -Kwok

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          • fredo6F Offline
            fredo6
            last edited by

            In general, interpolating points should be done with Geom.linear_combination
            in your case, to create nb intermediate segments ( so nb+1 points, including first and last one)

            
            def intermediate_points(pt1, pt2, nb)
               lpt = []
               for i in 0..nb
                  ratio = 1.0 * i / nb
                  lpt.push Geom.linear_combination(1 - ratio, pt1, ratio, pt2)
               end
               lpt
            end
            
            

            which you can write in a single line as well

            
            (0..nb).to_a.collect { |i| r = 1.0 * i /nb ; Geom.linear_combination(1-r, pt1, r, pt2) }
            
            

            Fredo

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            • Dan RathbunD Offline
              Dan Rathbun
              last edited by

              @kyyu said:

              You don't want to use a line. A line would have infinite length. Anyways, it's just seen as an array ( type "edge.line.class"). So the length of that array is always 2 elements in that array, which defines a line.

              Yes. I am sorry Korbin, meant to use the second element from the line method (got rushed.)

              I should have written:
              vec = edge.line[1] not vec = edge.line

              Also within a method, you dont need to use a global variable. Pass a reference to the line into the method as an argument. The argument name becomes a local reference (var) inside the method. (Do not get in the habit of using global vars. Its poor and lazy programming.)

              <span class="syntaxdefault">def draw_vision_field</span><span class="syntaxkeyword">(</span><span class="syntaxdefault"> edge </span><span class="syntaxkeyword">)<br /></span><span class="syntaxdefault">  ents </span><span class="syntaxkeyword">=</span><span class="syntaxdefault"> Sketchup</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">active_model</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">active_entities<br />  vision_field </span><span class="syntaxkeyword">=</span><span class="syntaxdefault"> </span><span class="syntaxkeyword">[</span><span class="syntaxstring">"test1"</span><span class="syntaxkeyword">,</span><span class="syntaxdefault"> </span><span class="syntaxstring">"test2"</span><span class="syntaxkeyword">,</span><span class="syntaxdefault"> </span><span class="syntaxstring">"test3"</span><span class="syntaxkeyword">,</span><span class="syntaxdefault"> </span><span class="syntaxstring">"test4"</span><span class="syntaxkeyword">,</span><span class="syntaxdefault"> </span><span class="syntaxstring">"test5"</span><span class="syntaxkeyword">]<br /></span><span class="syntaxdefault">  pt </span><span class="syntaxkeyword">=</span><span class="syntaxdefault"> edge</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">start</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">position<br />  puts pt<br />  vec </span><span class="syntaxkeyword">=</span><span class="syntaxdefault"> edge</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">line</span><span class="syntaxkeyword">[</span><span class="syntaxdefault">1</span><span class="syntaxkeyword">]</span><span class="syntaxdefault">       </span><span class="syntaxcomment"># fixed this <br /></span><span class="syntaxdefault">  vec</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">length </span><span class="syntaxkeyword">=</span><span class="syntaxdefault"> edge</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">length </span><span class="syntaxcomment"># added this<br /></span><span class="syntaxdefault">  puts vec<br />  num </span><span class="syntaxkeyword">=</span><span class="syntaxdefault"> vision_field</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">size </span><span class="syntaxkeyword">-</span><span class="syntaxdefault"> 1<br />  puts num<br />  seg </span><span class="syntaxkeyword">=</span><span class="syntaxdefault"> vec</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">length </span><span class="syntaxkeyword">/</span><span class="syntaxdefault"> num<br />  puts seg<br />  vec</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">length </span><span class="syntaxkeyword">=</span><span class="syntaxdefault"> seg<br />  vision_field</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">each_with_index </span><span class="syntaxkeyword">{|</span><span class="syntaxdefault">e</span><span class="syntaxkeyword">,</span><span class="syntaxdefault">i</span><span class="syntaxkeyword">|<br /></span><span class="syntaxdefault">    pt</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">offset</span><span class="syntaxkeyword">!(</span><span class="syntaxdefault">vec</span><span class="syntaxkeyword">)</span><span class="syntaxdefault"> if i </span><span class="syntaxkeyword">></span><span class="syntaxdefault"> 0<br />    ents</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">add_text</span><span class="syntaxkeyword">(</span><span class="syntaxdefault"> vision_field</span><span class="syntaxkeyword">[</span><span class="syntaxdefault">i</span><span class="syntaxkeyword">],</span><span class="syntaxdefault"> pt </span><span class="syntaxkeyword">)<br /></span><span class="syntaxdefault">  </span><span class="syntaxkeyword">}</span><span class="syntaxdefault"> <br />end<br /></span>
              

              EDIT: edge.line[1] returns a unit vector, so we must add a statement to make vec the length of edge.

              I'm not here much anymore.

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              • Dan RathbunD Offline
                Dan Rathbun
                last edited by

                @kdasilva said:

                how can I get 10 Point3d's evenly spread out along this line that I can use as anchors for my text....

                Divide the line by 9

                <span class="syntaxdefault">arr</span><span class="syntaxkeyword">=[]<br /></span><span class="syntaxcomment"># load array with the txt values in order<br /></span><span class="syntaxdefault">pt  </span><span class="syntaxkeyword">=</span><span class="syntaxdefault"> edge</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">start</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">position<br />vec </span><span class="syntaxkeyword">=</span><span class="syntaxdefault"> edge</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">line</span><span class="syntaxkeyword">[</span><span class="syntaxdefault">1</span><span class="syntaxkeyword">]<br /></span><span class="syntaxdefault">vec</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">length </span><span class="syntaxkeyword">=</span><span class="syntaxdefault"> edge</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">length <br />num </span><span class="syntaxkeyword">=</span><span class="syntaxdefault"> dict</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">size</span><span class="syntaxkeyword">-</span><span class="syntaxdefault">1<br />seg </span><span class="syntaxkeyword">=</span><span class="syntaxdefault"> vec</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">length </span><span class="syntaxkeyword">/</span><span class="syntaxdefault"> num<br />vec</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">length </span><span class="syntaxkeyword">=</span><span class="syntaxdefault"> seg<br />arr</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">each_with_index </span><span class="syntaxkeyword">{|</span><span class="syntaxdefault">e</span><span class="syntaxkeyword">,</span><span class="syntaxdefault">i</span><span class="syntaxkeyword">|<br /></span><span class="syntaxdefault">  pt</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">offset</span><span class="syntaxkeyword">!(</span><span class="syntaxdefault">vec</span><span class="syntaxkeyword">)</span><span class="syntaxdefault"> if i</span><span class="syntaxkeyword">></span><span class="syntaxdefault">0<br />  entities</span><span class="syntaxkeyword">.</span><span class="syntaxdefault">add_text</span><span class="syntaxkeyword">(</span><span class="syntaxdefault"> arr</span><span class="syntaxkeyword">[</span><span class="syntaxdefault">i</span><span class="syntaxkeyword">],</span><span class="syntaxdefault"> pt </span><span class="syntaxkeyword">)<br />}</span><span class="syntaxdefault"> </span>
                

                EDIT: vec = edge.line[1] was vec = edge.line
                Added: vec.length = edge.length as edge.line[1] returns a unit vector.

                I'm not here much anymore.

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                • Dan RathbunD Offline
                  Dan Rathbun
                  last edited by

                  @kyyu said:

                  You want to use the vector from the edge:

                  pt1 = edge.start.position
                  > pt2 = edge.end.position
                  > vec = Geom;;Vector3d.new [(pt2.x-pt1.x), (pt2.y-pt1.y), (pt2.z-pt1.z)]
                  > edge_length = vec.length
                  

                  This is what I intended, but left off the index to the 2nd element.
                  edge.line[1] returns the unit vector for the edge, so:

                  vec = edge.line[1] vec.length = edge.length

                  I'm not here much anymore.

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                  • K Offline
                    kdasilva
                    last edited by

                    Wow, thanks for all the help, and that fixed it up no problem.

                    Dan - I also got rid of all of the global variables...in some cases I used class variables I hope thats not bad coding...changes to a variable in one method needed to be consistent in other methods for some parts in the tool

                    (your all definitely getting a thank you foot note in my thesis!)

                    Cheers,
                    Korbin

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                    • Dan RathbunD Offline
                      Dan Rathbun
                      last edited by

                      @kdasilva said:

                      also... where does the method each_with_index come from?

                      The method each_with_index() comes from the special mixin-module Enumerable, which is mixed into many other classes like String, Hash and Array.

                      On the Docs page for each class, it lists what other modules are "mixed-in" using the include() method, so therefore the caption Included.
                      Array_included.png

                      And for Sketchup use the v 1.8.6 docs:
                      Core: http://www.ruby-doc.org/core-1.8.6/index.html

                      The Keywords apply to all branches and versions.
                      Keywords: http://www.ruby-doc.org/docs/keywords/1.9/

                      I'm not here much anymore.

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                      • Dan RathbunD Offline
                        Dan Rathbun
                        last edited by

                        @kdasilva said:

                        ...in some cases I used class variables I hope thats not bad coding...changes to a variable in one method needed to be consistent in other methods for some parts in the tool

                        No that's proper programing.. (and what I do,) if the tool instance is a singleton instance (the only instance of the tool class that will be instantiated, which is usually the case,) ... then using class variables is fine.

                        If it's an instance of a class that will have more than one instance "live" at a time, then instance variables (beginning with only 1 @,) would be what you want to use. (That way each instance has it's own set of the variables.)

                        You can also use class constants (is place of global constants,) and local variables (in place of global variables.)

                        I'm not here much anymore.

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                        • B Offline
                          bilianb
                          last edited by

                          @tig said:

                          pt=p.offset(vec, step)

                          Some help about the second argument \in API there is only one - vector\

                          Thanks

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                          • Dan RathbunD Offline
                            Dan Rathbun
                            last edited by

                            @bilianb said:

                            @tig said:

                            pt=p.offset(vec, step)

                            Some help about the second argument \in API there is only one - vector\

                            Take another look, at offset() not offset!()

                            Point3d.offset

                            I'm not here much anymore.

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                            • TIGT Offline
                              TIG Moderator
                              last edited by

                              point.offset() returns a new point from 'point', offset as specified BUT
                              point.offset**!**() offsets the original 'point', as specified.

                              TIG

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                              • K Offline
                                kyyu
                                last edited by

                                Ah, thanks for all the tips, guys! The line[1] vector will be useful, as long you are after the forward edge direction. I tried to use it yesterday, but couldn't because the polyline direction did matter in my case. And the second argument in .offset(). I didn't realize there was a second argument and was scaling my vector, instead. Actually, I only recently realized you could scale a vector by vector.length= and had been doing it a harder way, before.

                                -Kwok

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