Purpose: To cover a rectangular region with surface patches.
Card:
SM I1 I2 F1 F2 F3 F4 F5 F6 blank
NX NY X1 Y1 Z1 X2 Y2 Z2
A second card with the following format must immediately follow
a SM card:
SC F1 F2 F3 F4 F5 F6 blank
X3 Y3 Z3
Parameters:
Integers:
NX (I1) \ The rectangular surface is divided into NX patches
| from corner 1 to corner 2 and NY patches from
NY (I2) / corner 2 to corner 3.
Decimal Numbers:
X1 (F1) \
Y1 (F2) | X, Y, Z coordinates of corner 1
Z1 (F3) /
X2 (F4) \
Y2 (F5) | X, Y, Z coordinates of corner 2
Z2 (F6) /
X3 (F7) \
Y3 (F8) | X, Y, Z coordinates of corner 3
Z3 (F9) /
Notes:
o The division of the rectangle into patches is as illustrated in
figure 6 "Rectangular Surface Covered by Multiple Patches".
o The direction of the outward normals ^n of the patches is determined
by the ordering of corners 1, 2, and 3 and the right-hand rule. The
vectors ^t1 are parallel to the side from corner 1 to corner 2 and
^t2 = ^n x ^t1. The patch may have arbitrary orientation.
o If the sides between corners 1 and 2 and between corners 2 and 3 are
not perpendicular, the complete surface and the individual patches
will be parallelograms.
o Multiple SC cards are not allowed with SM.
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