Skip Talbot wrote:
> Is there a way to accurately, or quickly and fairly accurately, 
> subdivide a spline into equal lengths?  I've written a macro that takes 
> small steps along the spline and sums up the distance between the steps. 
>   I then divide this length by the number of segments I want, and 
> traverse the spline again until this divided distance is reached.  The 
> lengths always fall short (as well they should as I lose the curvature). 
> The smaller the step the better the accuracy but the parse times start 
> getting fairly high.  Less obvious though is that the error increases as 
> I increase the number of divisions.  It almost seems like its skipping 
> the last step and distance sum for the segment, and thus they the error 
> adds up with more segments.
> 
> Does anyone have a better approach to this problem or should I scour my 
> macro for bugs?
> 
> Skip
Sounds like first of all you need to define the spline so that equal 
deltas of the clock value will produce equal intervals along the spline

I use a fairly crude macro for this which suits natural splines

#macro SmoothSpline( Spline, Grain )
//regularizes the spline definition so
//the distance along the spline will be
//more proportional to the clock value
         #local TL=0;
         #local Ptr=1;#while(Ptr<=Grain)
                 #local TL=
                         TL+vlength( Spline(Ptr/Grain)
                         -Spline((Ptr-1)/Grain) );
         #local Ptr=Ptr+1;#end


         #local L=0;

         spline { 

                 natural_spline
                 0 Spline(0)
                 #local Ptr=1;#while(Ptr<=Grain)
                         #local L=
                                 L+vlength( Spline(Ptr/Grain)
                                 -Spline((Ptr-1)/Grain) );

                                 L/TL Spline(Ptr/Grain)
                 #local Ptr=Ptr+1;#end
         }

#end

Then you can divide the spline into equal lengths using equal clock 
deltas.

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