# Shapes

A variable number of 'points' (one in each line of the input file), each having a maximum of 3 values, can be stored in the program. Apart from the shapes with 8 corners (BOX , TRAP, TRD1) the parameter are at least very similar to the ones in Geant. Except for a TRAP and a TRD1 the intrinsic coordinate systems are defined as in Geant.

BOX
This shapes has 8 corners described by the x, y, z coordinates.

TRAP
This shapes has 8 corners described by the x, y, z coordinates. The corners are counted clockwise starting at the lower left corner of the bottom plane. The intrinsic coordinate system of a TRAP is different from the one in Geant. The y-axis points from the smaller side in x-direction to the larger one. A TRAP not rotated in a Box has the same intrinsic coordinate system as the BOX. In Geant the y- and x-axis point in the opposite directions.

TRD1
This shapes has 8 corners described by the x, y, z coordinates. The intrinsic coordinate system of a TRD1 is the same as for a TRAP. That's different from the definition in Geant.

PGON
This shape has a variable number of 'points'.

• point 0: NZ number of planes perpendicular to the z-axis where the section is given
• point 1: azimuthal angle PHI1 at which the volume begins
opening angle DPHI of the volume
number NPDV of sides of the cross section between the phi limits
• point 2ff:
• z coordinate Z of the section
• inner radius RMIN at position z
• outer radius RMAX at position z

PCON

This shape has a variable number of 'points'.

• point 0: NZ number of planes perpendicular to the z-axis where the section is given
• point 1: azimuthal angle PHI1 at which the volume begins
opening angle DPHI of the volume
• point 2ff:
• z coordinate Z of the section
• inner radius RMIN at position z
• outer radius RMAX at position z

SPHE
This shape has 3 'points' with 2 parameters each.

• Point 0: inner radius RMIN of the shell
outer radius RMAX of the shell
• point1: starting polar angle THE1 of the shell
ending polar angle THE2 of the shell
• point 2: starting azimuthal angle PHI1 of the shell
ending azimuthal angle PHI2 of the shell

TUBE
This shape has 3 'points'.

• point 0: x, y, z coordinate of the center of the circle at the beginning of the tube
• point 1: inner radius RMIN of the tube
outer radius RMAX of the tube
• point 2: x, y, z coordinate of the center of the circle at the end of the tube

TUBS

This shape has 4 'points'.

• point 0: x, y, z coordinate of the center of the circle at the beginning of the tubs
• point 1: inner radius RMIN of the tubs
outer radius RMAX of the tubs
• point 2: x, y, z coordinate of the center of the circle at the end of the tubs
• point 3: starting angle PHI1 of the segment
ending angle PHI2 of the segment

CONE

This shape has 4 'points'.

• point 0: x, y, z coordinate of the center of the circle at the beginning of the cone
• point 1: inner radius RMN1 at the beginning of the cone
outer radius RMX1at the beginning of the cone
• point 2: x, y, z coordinate of the center of the circle at the end of the cone
• point 3: inner radius RMN2 at the end of the cone
outer radius RMX2 at the end of the cone

CONS

This shape has 5 'points'.

• Point 0: x, y, z coordinate of the center of the circle at the beginning of the cons
• point 1: inner radius RMN1 at the beginning of the cons
outer radius RMX1 at the beginning of the cons
• point 2: x, y, z coordinate of the center of the circle at the end of the cons
• point 3: inner radius RMN2 at the end of the cons
outer radius RMX2 at the end of the cons
• point 4: starting angle PHI1 of the segment
ending angle PHI2 of the segment

ELTU

This shape has 3 'points'.

• point 0: x, y, z coordinate of the center of the ellipsoid at the beginning of the eltu
• point 1: semi-axis P1 along x
semi-axis P2 along y
• point 2: x, y, z coordinate of the center of the ellipsoid at the end of the eltu

Warning: A TUBE, TUBS, CONE, ELTU can not be rotated by different x- and y-values of the starting and ending circles. They have to be identical. A rotation can only be described by a rotation matrix.

TORUS

This shape has 5 'points'. (not available in native Geant3!!)

• point 0: R - axial radius
• point 1: Rmin - inner radius
• point 2: Rmax - outer radius
• point 3: Phi1 - starting phi
• point 4: Dphi - phi extent