General principle of the M6Geo geometry

The geometry is defined between the keywords GEOM and ENDG. It is composed of volumes, each defined by:

  • a shape (specified using the TYPE keyword) chosen from a predefined set;

  • a position within the module;

  • relationships with other volumes in the module.

The primary component of the geometry is the module, which is delimited by the MODU and ENDM keywords. Modules are volume combinations that can be used in several locations within the geometry without needing to repeat their definition. Each module can be thought of as a “local” geometry with its own:

  • coordinate system;

  • types and volumes;

  • external volume.

Modules can be inserted into each other using holes. Every volume must be contained within a module.

Modules are sequenced in the geometry as follows:

Block syntax
GEOM

  MODU 0  * Module 0 is always required
    * module description
  ENDM
    * module description
  MODU id
    * module description
  ENDM
ENDG

The description of a modular geometry is governed by the following rules:

  • Modules can be described in any order within the GEOM block;

  • The main module MODU 0 is always required;

  • The external volume of the main module (i.e. MODU 0) serves as the external volume of the global geometry;

  • The external volume of a module encompasses all volumes related to the module;

  • The external volume must be enclosed (TYPE of type BOX, SPHE, ELLI, CYL(X|Y|Z), HEX(X|Y|Z), or MPLA keywords);

  • The external volume must not use geometrical operators.

Note

The names of holes, volumes, and types are independent (i.e. a type may share the same name as a volume).