GEANT321/ggeom/gnotr9.F

   1 *
   2 * $Id$
   3 *
   4 * $Log$
   5 * Revision 1.1.1.1  1995/10/24 10:20:53  cernlib
   6 * Geant
   7 *
   8 *
   9 #include "geant321/pilot.h"
  10 *CMZ :  3.21/02 29/03/94  15.41.30  by  S.Giani
  11 *-- Author :
  12       SUBROUTINE GNOTR9(X,Y,Z,N1,N2,N3,N4)
  13 C.    ******************************************************************
  14 C.    *                                                                *
  15 C.    *     GNOTR9 checks coplanarity of the face described by the     *
  16 C.    *     indices N1,N2,N3,N4 into the vertex array X,Y,Z.           *
  17 C.    *     This check is perfomed since shape TRAP is described by    *
  18 C.    *     11 values in the parameter array of which only 9 are       *
  19 C.    *     independant.
  20 C.    *         Called by : GNOTR2
  21 C.    *         Author  R.Nierhaus  *********                          *
  22 C.    *                                                                *
  23 C.    ******************************************************************
  24 *
  25 #include "geant321/gcunit.inc"
  26 *
  27       DIMENSION X(8),Y(8),Z(8)
  28 *
  29       A=-((Y(N2)-Y(N1))*(Z(N3)-Z(N1))-(Y(N3)-Y(N1))*(Z(N2)-Z(N1)))
  30       B=-((Z(N2)-Z(N1))*(X(N3)-X(N1))-(Z(N3)-Z(N1))*(X(N2)-X(N1)))
  31       C=-((X(N2)-X(N1))*(Y(N3)-Y(N1))-(X(N3)-X(N1))*(Y(N2)-Y(N1)))
  32       V=(X(N4)-X(N1))*A+(Y(N4)-Y(N1))*B+(Z(N4)-Z(N1))*C
  33       IF (ABS(V)/SQRT(A**2+B**2+C**2).GT.1.E-3) THEN
  34          WRITE(CHMAIL,1001)
  35          CALL GMAIL(0,0)
  36  1001    FORMAT (' GNOTR9 ...TRAP shape :  surface not coplanar')
  37       END IF
  38 *
  39       END
  40