ufo academic forum

1. andrea
   Member
   Posted 1 year ago #
   

   hi, does anyone know of a way of selecting only features with odd indexes?
   ie: I want to project a series of curves onto a surface. The curves come in pairs and their indexes are:
   -bsplinecurve[0][0] -bsplinecurve[1][0]
   -bsplinecurve[0][1] -bsplinecurve[1][1]
   -bsplinecurve[0][7] -bsplinecurve[1][7]
   -bsplinecurve[0][8] -bsplinecurve[1][8] and so on....for many curves
   I would like to project only those ending in [x][1] or [x][7]. Is there a way of writing this?
   [x][odd], or [x][i+1] or something along those lines?

2. gustav
   Administrator
   Posted 1 year ago #
   

   one way of accessing a certain progression of numbers is by modulo division. it gives the remainder afetr integer division; 5 mod 2 equals 3 and so on. look it up on mathworld or wikipedia for details if needed, but the present application would be something like:

   i mod 7 = 0 isolates the series {0,7,14,21...}

   i mod 3 = 2 isolates the series {5,8,11,14...}

   if you're actually only out to step between 2nd-depth indices 1 and 7 always, then just make the nested loop

   for (i=0;i<whatever.count;i++)
   {
   for (j=0;j<whateverother.count;j++)
   {
   BSplineCurve projectedcurve = new BSplineCurve(this)

   if (j mod 6 = 1)
   {
   projectedcurve.ByProjectionOnPlane(originalbsplinecurve[i][j], whateverPlane)
   }
   }
   }

   Now I'm writing from memory so you might have to tweak it a little to actually output into the model space again.

   HTH

   G

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