GetEdgeCount() Bug?



  • THE POST BELOW IS MORE THAN 5 YEARS OLD. RELATED SUPPORT INFORMATION MIGHT BE OUTDATED OR DEPRECATED

    On 05/02/2012 at 11:49, xxxxxxxx wrote:

    User Information:
    Cinema 4D Version:   12 
    Platform:   Windows  ;   
    Language(s) :

    ---------
    I'm not getting the correct results from GetEdgeCount(). It's not returning the correct amount of edges in an object. It always comes up short.
    I'm testing this in Python. But since Python is just wrapping around the C++ API. It might be coming from C++.

    Here's an example:

    import c4d  
    from c4d import utils  
      
    def main() :  
      obj = doc.GetActiveObject()      #A cube object  
      nibr = utils.Neighbor()          #Assigns neighbor to a variable  
      nibr.Init(obj)                   #Instantiates the neighbor class using the "obj"  
      edgecount = nibr.GetEdgeCount()  #Get all the edges in the entire polygon object  
      print edgecount    #Prints 12!? <----This should be 16!!!                  
      
      edges = c4d.BaseSelect() #Create a BaseSelect object  
      
      mylist = [x for x in range(edgecount)] #Creates an array size based on GetEdgeCount()   
      print mylist  
      edges.SetAll(mylist)  
      
      edges.CopyTo(obj.GetEdgeS())  #Makes the edges selected in the scene from memory  
                                    #Only 12 edges are selected because GetEdgeCount() failed!?  
      
      c4d.EventAdd()  
      
    if __name__=='__main__':  
      main()
    

    When I use this on a more complex object. The number of missed edges climbs.
    Is this a bug?

    Update:
    I got a chance to try this is in C++ and got the same wrong edge count results:

        BaseDocument *doc = GetActiveDocument();  
      BaseObject *op = doc->GetActiveObject();  //A cube object  
      if (!op) return FALSE;  
      
      if (op->GetType() == Opolygon)  
      {  
       Neighbor n;  
       if (!n.Init(ToPoly(op)->GetPointCount(),ToPoly(op)->GetPolygonR(),ToPoly(op)->GetPolygonCount(),NULL)) return FALSE;  
      
       LONG ecount = n.GetEdgeCount();    // Count the edges in the object  
       GePrint(LongToString(ecount));     //<---Prints 12!?.......Should be 16!!!
    

    Could someone from Maxon please confirm this as either bug, or user error.
    I can't use it until I know what's really going on with it.

    -ScottA



  • THE POST BELOW IS MORE THAN 5 YEARS OLD. RELATED SUPPORT INFORMATION MIGHT BE OUTDATED OR DEPRECATED

    On 05/02/2012 at 14:59, xxxxxxxx wrote:

    This is very confusing.

    -There are 24 edges in a cube. If you count each polygon as a separate face
    -GetEdgeCount() returns 12 edges. So using that I end up with all but three edges selected
    -If I use an array with 16 elements in it as the source for SetAll(myarray). Every edge of the cube is selected as expected.

    All I want to do is use GetEdgeCount() to get the number of edges in an object. Like the name of the function implies. Then use that number to select them later on.
    But it looks like I can't do that because GetEdgeCount() does not count every single edge as the name implies.

    What it looks like I'm having trouble with. Is figuring out how these various functions determine what an edge is. And when they are/and are not, counting them.

    -If I use edgecount = nibr.GetEdgeCount()*2 it does select all the edges of a cube.
    -If I use edgecount = nibr.GetEdgeCount()*2 on a plane. It selects all but one edge.
    -If I use edgecount = nibr.GetEdgeCount()*2 on a  sphere. I get five unselected  edges at the poles.

    Is this the desired result for GetEdgeCount() ?
    The more I try to use it. The more confused I get. 😵

    -ScottA



  • THE POST BELOW IS MORE THAN 5 YEARS OLD. RELATED SUPPORT INFORMATION MIGHT BE OUTDATED OR DEPRECATED

    On 06/02/2012 at 09:33, xxxxxxxx wrote:

    If you look at PolygonObject.GetSelectedEdges() documentation, it's stated that: "The edges are indexed uniquely by a Neighbor object, so each edge has a single index."
    So there are only 12 edges in a cube. We can see that looking at the information returned by Neighbor.GetPolygonCount() :

    for i in xrange(op.GetPolygonCount()) :
        pli = nbr.GetPolyInfo(i)
        print pli
    

    There's some missing documentation for the information returned by Neighbor.GetPolygonCount() for the Python docs. You can take a look at the C++ docs for this method.
    'mark' indicates if an edge is new or was already built. There are 12 False 'mark' and 12 True 'mark'.

    BaseSelect.SetAll() accepts an array of selection states , 0 or 1 values, not indices. So you should build the edges selection array like this:

    mylist = [1 for x in range(edgecount)]
    

    And to select edges it works as expected calling PolygonObject.SetSelectedEdges().



  • THE POST BELOW IS MORE THAN 5 YEARS OLD. RELATED SUPPORT INFORMATION MIGHT BE OUTDATED OR DEPRECATED

    On 06/02/2012 at 10:51, xxxxxxxx wrote:

    Originally posted by xxxxxxxx

    And to select edges it works as expected calling PolygonObject.SetSelectedEdges().

    Thanks for the help Yannick.
    But I still can't select all edges of a polygon object using that information.
    Example:

    import c4d  
    from c4d import gui,utils  
      
    def main() :  
      
      obj = doc.GetActiveObject()       #A cube object  
      nbr = utils.Neighbor()            #Assigns neighbor to a variable  
      nbr.Init(obj)                     #Instantiates the neighbor class using the "obj"  
      edgecount = nbr.GetEdgeCount()    #Get all the edges in the entire polygon object  
      
      for i in xrange(op.GetPolygonCount()) :  
          pli = nbr.GetPolyInfo(i)  
          print pli  
      
      mylist = [1 for x in range(edgecount)] #Set all edges to True  
      
      obj.SetSelectedEdges(nbr,mylist,c4d.EDGESELECTIONTYPE_SELECTION)#<--Error:c4d.PolygonObject has no attribute 'SetSelectedEdges'  
      
    if __name__=='__main__':  
      main()
    

    Any chance of seeing a proper working example of this?

    Thanks,
    -ScottA



  • THE POST BELOW IS MORE THAN 5 YEARS OLD. RELATED SUPPORT INFORMATION MIGHT BE OUTDATED OR DEPRECATED

    On 06/02/2012 at 11:18, xxxxxxxx wrote:

    Ah... you may be using a pre-R13 version. SetSelectedEdges() was added to the Python SDK in version R13.

    Here's how to do without SetSelectedEdges() :

    import c4d
    from c4d import utils
      
    def main() :
        nbr = utils.Neighbor()
        nbr.Init(op)
        indices = [1 for i in range(nbr.GetEdgeCount()*2)]
        edges = c4d.BaseSelect()
        edges.SetAll(indices)
      
        edges.CopyTo(op.GetEdgeS())
        c4d.EventAdd()
      
    if __name__=='__main__':
        main()
    

    SetSelectedEdges() works with unique edges but GetEdgeS() not. I just reversed engineered GetEdgeS() getting the current selection and it's 24 edges when we select all the edges. In R13 with GetSelectedEdges() it's 12 edges. So it's more or less what you tried before 🙂 except the edges array is built with selection states values.



  • THE POST BELOW IS MORE THAN 5 YEARS OLD. RELATED SUPPORT INFORMATION MIGHT BE OUTDATED OR DEPRECATED

    On 06/02/2012 at 12:11, xxxxxxxx wrote:

    Lol.
    Isn't it fun trying to troubleshoot these functions when they get updated so often from version to version?😉
    That code you posted brings me back to my original problem.
    *2 works for a cube. But it does not select all edges on a sphere for example.
    I've even tried multiplying nbr.GetEdgeCount() * 3.02 and that still doesn't work in all cases.
    But lets forget about R12 at this point. And call it not supported. And just focus on R13 from now on...OK?
    No sense trying to get the older version to work at this point.

    Can you please post a code example that selects all edges in an object for R13 using the "op.SetSelectedEdges" function?
    But before you post it. Please try it out on both a cube and a sphere.
    I'm still getting the same results in R13 as r12. And I want to see if you get the same results.

    Thanks,
    -ScottA



  • THE POST BELOW IS MORE THAN 5 YEARS OLD. RELATED SUPPORT INFORMATION MIGHT BE OUTDATED OR DEPRECATED

    On 06/02/2012 at 12:27, xxxxxxxx wrote:

    Originally posted by xxxxxxxx

    Can you please post a code example that selects all edges in an object for R13 using the "op.SetSelectedEdges" function?
    But before you post it. Please try it out on both a cube and a sphere.
    I'm still getting the same results in R13 as r12. And I want to see if you get the same results.

    Here's the working code for any polygon object in R13 using SetSelectedEdges() :

    import c4d
    from c4d import utils
      
    def main() :
        nbr = utils.Neighbor()
        nbr.Init(op)           # Initialize neighbor with a polygon object
        
        selection = [1 for i in range(nbr.GetEdgeCount())] # Select all the edges = set them to 1
        edges = c4d.BaseSelect()
        edges.SetAll(selection)                            # Set the edges selection with the selection list
      
        op.SetSelectedEdges(nbr, edges, c4d.EDGESELECTIONTYPE_SELECTION) # Select edges from our edges selection
        c4d.EventAdd() # Update CINEMA
      
    if __name__=='__main__':
        main()
    


  • THE POST BELOW IS MORE THAN 5 YEARS OLD. RELATED SUPPORT INFORMATION MIGHT BE OUTDATED OR DEPRECATED

    On 06/02/2012 at 12:34, xxxxxxxx wrote:

    Excellent.
    I think I've got it all sorted out now.

    Thanks a lot for sticking with me on this one.🍺

    -ScottA



  • THE POST BELOW IS MORE THAN 5 YEARS OLD. RELATED SUPPORT INFORMATION MIGHT BE OUTDATED OR DEPRECATED

    On 06/02/2012 at 12:53, xxxxxxxx wrote:

    If you want to select all edges you should be able to use

      
    edges.SelectAll(edgecount)   
    obj.SetSelectedEdges(nibr,edges,c4d.EDGESELECTIONTYPE_SELECTION)   
    


  • THE POST BELOW IS MORE THAN 5 YEARS OLD. RELATED SUPPORT INFORMATION MIGHT BE OUTDATED OR DEPRECATED

    On 06/02/2012 at 13:16, xxxxxxxx wrote:

    Yeah. That's true Lennart.

    I'm using arrays in my examples because it gives me a way to iterate through my selections.
    AFAIK. BaseSelection is not iterable. That's why I'm using arrays(lists) in my code.

    Probably a good idea that you pointed that out for the sake of others new to this subject that don't need or want that extra iteration ability.

    -ScottA



  • THE POST BELOW IS MORE THAN 5 YEARS OLD. RELATED SUPPORT INFORMATION MIGHT BE OUTDATED OR DEPRECATED

    On 06/02/2012 at 15:17, xxxxxxxx wrote:

    You could iterate using enumerate and get a list:

      
    # Get Set Edges Test R13   
    import c4d   
    from c4d import utils as u   
      
    def main() :   
        obj = doc.GetActiveObject()   
        if obj is None or not obj.CheckType(c4d.Opolygon) :   
            return True   
        n   = u.Neighbor()   
        n.Init(obj)   
        edgecount = n.GetEdgeCount()   
        print edgecount   
        edges = obj.GetSelectedEdges(n, c4d.EDGESELECTIONTYPE_SELECTION)   
        elist = []   
        for i, sel in enumerate(edges.GetAll(edgecount)) :   
            if sel: elist.append(1)   
            else:   elist.append(0)   
        print elist   
        edges.SetAll(elist)   
        obj.SetSelectedEdges(n, edges, c4d.EDGESELECTIONTYPE_SELECTION)   
        c4d.EventAdd()   
      
    if __name__=='__main__':   
        main()   
    


  • THE POST BELOW IS MORE THAN 5 YEARS OLD. RELATED SUPPORT INFORMATION MIGHT BE OUTDATED OR DEPRECATED

    On 06/02/2012 at 17:59, xxxxxxxx wrote:

    Yeah I know. That's what I've been doing in R12.
    Although lately I've been using a different method where I iterate from inside of the the lists themselves.
    Same difference.😉

    I got hung up on trying to select all edges. GetEdgeCount() didn't work as I expected it to work.
    I'm good to go now. Except that now I'm forced to use R13. 😠

    I'm still thinking that this should be possible to do in R12 though.
    Since we can iterate selections using lists. I would think that we should be able to step through the polygons and get & set every edge that way. But I couldn't make it work.
    It might  require getting each polygon point(A,B,C,D).
    Then using that to find all the edges. And putting that into a list.
    Then using that list to select the edges.

    That's kind of advanced stuff for me right now. I'm still not very good with polygons & edges.

    -ScottA



  • THE POST BELOW IS MORE THAN 5 YEARS OLD. RELATED SUPPORT INFORMATION MIGHT BE OUTDATED OR DEPRECATED

    On 07/02/2012 at 01:28, xxxxxxxx wrote:

    Originally posted by xxxxxxxx

    I got hung up on trying to select all edges. GetEdgeCount() didn't work as I expected it to work.
    I'm good to go now. Except that now I'm forced to use R13. 
    I'm still thinking that this should be possible to do in R12 though.

    Here's the code for R12:

    import c4d
    from c4d import utils
      
    def main() :  
        numEdges = op.GetPolygonCount()*4
        
        edges = c4d.BaseSelect()
        edges.SelectAll(numEdges-1)
      
        edges.CopyTo(op.GetEdgeS())
        c4d.EventAdd()
      
      
    if __name__=='__main__':
        main()
    

    As you can see, the number of edges is the number of polygons multiplied by 4 (4 edges per polygon). GetEdgeS() doesn't work with shared edges, Neighbor and the methods using it (GetSelectedEdges(), SetSelectedEdges()) do.
    I select all the edges to numEdges-1 and not to numEdges because I found an issue with SelectAll(). The number of selected elements is number+1 the number you pass to the method.



  • THE POST BELOW IS MORE THAN 5 YEARS OLD. RELATED SUPPORT INFORMATION MIGHT BE OUTDATED OR DEPRECATED

    On 07/02/2012 at 08:01, xxxxxxxx wrote:

    Thanks for that Yannick.
    But I should have mentioned that I needed to be able to select all edges using a list. I'll see if I can use this in my project using lists.

    This is all based on a bigger project I'm working on. Where I'm trying to select just one side of the outer edges of "shells" (also known as "islands" ) inside of a polygon. And convert them to splines.
    Maya has tools and functions for working with polygon and UV shells and I'm trying to build my own in C4D.
    Currently the only way I can do this is to use the ExplodeSegments command. Then select the desired edges on each generated polygon object.
    This works ok. (I posted the script on CGTalk) But the problem is I have to generate thousands of objects this way(Ouch!). Just to generate those splines. And that's both very slow and very resource hungry. And frankly a bit of a hack.

    So now I'm trying to use lists to try and cut these shells inside the polygon into groups so I can work with them as if they were individual objects. Sort of like using lists in place of a selection tags.
    I need to be able to select all edges...But not just simply all edges. All edges per each shell... And not just all edges..But only the edges on one side of all these shells.
    It's a rather complex problem.

    I posted about it in another thread in the C++ forum.
    The source code in the ExplodeSegments command might help me learn how to split up a polygon into groups. I don't even know if my approach is a good one.

    This is what I've come up with so far.
    It's almost there(it currently only selects the first shell's edges). But then I ran into selection problems:

    import c4d  
    from c4d import utils  
      
    def main() :  
      
    ################## Put polygon shells into an array #####################################  
      c4d.CallCommand(12187)  #Polygons Mode  
      c4d.CallCommand(13324)  #Deselect All polygons--Start from no polygons selected  
      lastsel = 0  
      
      obj = doc.GetActiveObject()     
      polycount = obj.GetPolygonCount()  
      selected = obj.GetPolygonS()       #The selected polygons  
      selected.Select(0)                 #Select the first polygon  
      c4d.CallCommand(12557)             #Select Connected polygons  
      selectedcount = selected.GetCount()#How many polygons per shell  
      polygons = c4d.BaseSelect()  
      polysPerShell = 0                  #The number of polygons per shell  
      
      polygonlist = []    #The list of shell arrays(contains the individual lists for each shell)   
      
      for i in xrange(polycount/selectedcount) :  
          #print "shells:" ,i  
          newpolygonlist = []              #This list will be used to hold the selected polygons  
          for i in xrange(polycount) :      #Loop amount = total number of polygons  
              if selected.IsSelected(i) :   #Look for selected polygons  
                   polysPerShell = polysPerShell +1  #The number of polygons per shell                 
                   newpolygonlist.append(i)#Fill the list with the selected polygons  
                   lastsel = i             #This is the last selected polygon's Id#  
            
          polygonlist.append(newpolygonlist)  
          c4d.StatusSetSpin()              #Show the spinning staus bar  
          c4d.CallCommand(13324)           #Deselect All polygons  
          selected.Select(lastsel+1)       #Select the first polygon in the next shell   
          c4d.CallCommand(12557)           #Select Connected polygons  
    ################### Done with loop #################################################  
         
      pnts = obj.GetAllPoints()  
      edges = c4d.BaseSelect()  
      pntcount = obj.GetPointCount()  
      nibr = utils.Neighbor()          #Assigns neighbor to a variable  
      nibr.Init(obj)                   #Instantiates the neighbor class  
      edgecount = nibr.GetEdgeCount()  #Get all the edges in the entire polygon object  
      #print "total edges:", + edgecount     
      #print polysPerShell               
       
      shellpolylist = []  
      
      for i in xrange(len(polygonlist)) : #This gives the number of shells  
          shells = i                         
          #print shells  
          for shells in polygonlist:     #For each shell of polygons in the "polygonlist" array  
              #print shells  
               for j in xrange(0,polysPerShell) : #For each shell element  
                   #print j                  
                   selected.Select(j)            #Select each element(polygon)                   
                   shellpolylist.append(j)       #Add each polygon to the list  
      
          edges.Select(shellpolylist[1])  
          edges.Select(shellpolylist[5])  
          edges.Select(shellpolylist[9])  
      #print shellpolylist  
      edges.CopyTo(obj.GetEdgeS())  
      
      #Convert selected objects to splines  
      utils.SendModelingCommand(c4d.MCOMMAND_EDGE_TO_SPLINE, list = [obj], mode = c4d.MODIFY_ALL, bc = c4d.BaseContainer(), doc = doc)  
      
      c4d.CallCommand(16351)            #Edges    
      c4d.StatusClear()                 #Remove the spinning bar..We're done  
      #print edgelist  
      c4d.EventAdd()      
      
    if __name__=='__main__':  
      main()
    

    I'm not sure if I'm on the right track or not.
    I'm in a little bit over my head. And just looking for advice on doing this.
    Not really a support issue. Just wanted to let you see what I was trying to do in the bigger picture.

    -ScottA


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