A PYX (PYY, PYZ) is a pyramid parallel to the x (y, z) axis. It Can be full or truncated Each PYX (PYY, PYZ) is defined by 7 parameters: V_x, V_y, V_z, (coordinates of the centre of the major base) L_y, L_z (res.p L_z, L_x or L_x, L_y) half-lengths of the sides of the major base H : height of the pyramid. The sign gives the direction from major to minor basis R : ratio between the sides of the minor base and the sides of the major base. If R=0.0, the pyramid is not truncated. R>=1. is not accepted Example PYZ body3 0.0 0.5 -10.0 +20.0 +40.0 50.0 0.8 Is a truncated pyramid with major base centered at 0.0, 0.5,-10.0 and extending from x=-20.0 to x=+20, and from y=-39.5 to y=40.5. Its axis is along z, its height is 50 cm, the minor basis extends from -16.0 to +16.0 in x and from -31.5 to 32.5 in y NOTE +---------------------------------------------------------------------+ | Whenever it is possible, the following bodies should be preferred: | | PLA, PYX, PYY, PYZ, QUA, RPP, SPH, XCC, XEC, XYP, XZP, YCC, | | YEC, YZP, ZCC, ZEC | | These should indeed make tracking faster, since for them extra | | coding ensures that unnecessary boundary intersection calculations | | are avoided when the length of the next step is smaller than the | | distance to any boundary of the current region. | +---------------------------------------------------------------------+