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CAD tip # 1366:

Question CAD
% platform category

How to generate a random number using AutoLISP?

Use the following function for a LISP generator of pseudo-random numbers:

(defun rnd (/ modulus multiplier increment random)
  (if (not seed)
    (setq seed (getvar "DATE"))
  )
  (setq modulus    65536
        multiplier 25173
        increment  13849
        seed  (rem (+ (* multiplier seed) increment) modulus)
        random     (/ seed modulus)
  )
)

Each call of the function (rnd) then returns a pseudo-random number in the range (0,1). E.g. to get random integers from 0 to 20, use (fix(* 20 (rnd))).

ACAD

* CAD

1.6.2001 14994×

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applies to: AutoCAD ·

See also:
Tip 12448:	Pan view (change view target) in multiple viewports of a layout.
Tip 12446:	Quick 1-/2-click dimensioning in AutoCAD.
Tip 12368:	Gaps - how to find loose ends on lines in a DWG?
Tip 12310:	How to check if a dimension is associative or not? (LISP)
Tip 12306:	How to check if a specific application or process is running?

Selected tip: How to place an unprintable entity in a drawing?

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