/Trap

/Trap is a skewed version of /Trd, i.e., asymmetric pyramid with its upper part cut away. Its top and bottom facets are asymmetric trapezoids. Its skew is expressed with direction of a line joining the centers of the top and bottom trapezoids. (Here we define a center of a trapezoid by an intersection point of two lines passing through middle points of opponent edges.) This line should pass through the origin. The top trapezoid is on plane z = +dz, and the bottom trapezoid on plane z = -dz. Note that there are 11 parameters, but only 9 are really independent. Meanings of some parameters are similar to those of /Parallelepiped. /Trap corresponds to class G4Trap of GEANT4.

Format /Trap dz theta phi h1 bl1 tl1 alpha1 h2 bl2 tl2 alpha2

dz half height of this shape along the z axis

theta polar angle of the line expressing skew

phi azimuthal angle of the line expressing skew

h1 half height of the bottom trapezoid along the y axis

bl1 half length along the x direction of the side at minumum y of the bottom trapezoid

tl1 half length along the x direction of the side at maximum y of the bottom trapezoid

alpha1 angle formed the y axis and a line joining middle points of the two x-directional edges of the bottom trapezoid

h2 half height of the top trapezoid along the y axis

bl2 half length along the x direction of the side at minimum y of the top trapezoid

tl2 half length along the x direction of the side at maximum y of the top trapezoid

alpha2 angle formed the y axis and a line joining middle points of the two x-directional edges of the bottom trapezoid