1. Spacecraft Environment & Protection Group GEANT4 Workshop, ESTEC, 20-24, Sep. 1999 A CAD/Geant4 Front-end Interface Fan Lei Space Department, Defence Evaluation & Research Agency, Farnborough, UK Rodolfo Gurriaran Department of Physics & Astronomy, University of Southampton Southampton, UK (Some images and data in this presentation courtesy of PDES Inc.)

2. Spacecraft Environment & Protection Group GEANT4 Workshop, ESTEC, 20-24, Sep. 1999 Introduction n A front-end user interface to allow space engineers to import CAD model into the Geant4 based space radiation shielding calculation tools. n The development process has been divided into two phases –Phase I: Investigate compliance of major CAD tools with STEP protocol or future trends in this direction. Define a set of user requirements for a CAD front-end interface for the space radiation effects community. Assess their possible application as a front-end for geometry/material definition for G4 based tools. –Phase II: The design and development of the front-end interface. The final esign is a combination of a CAD system and a Material Generation & Association tool. The later is adapted from GGE. n The work has been carried out by University of Southampton

3. Spacecraft Environment & Protection Group GEANT4 Workshop, ESTEC, 20-24, Sep. 1999

4. Spacecraft Environment & Protection Group GEANT4 Workshop, ESTEC, 20-24, Sep. 1999

5. Spacecraft Environment & Protection Group GEANT4 Workshop, ESTEC, 20-24, Sep. 1999 Some Comments n AP203 ISO standard since 1994 n The compliance of CAD systems is evolving fast n Many CAD system claim to be compliant, but in reality only partial –some “old” STEP files forget the “management” information (class1) –AutoCAD R15 partially implement class1, not class 3 nor 5. –CATIA the first to be certified conformant with the STEP international standard (AP203) n PDES generated a “Recommended Practices for AP203” in 1998: –class 1 is required. n For this work, class 1 “management information” must be present (“PRODUCT” field)

6. Spacecraft Environment & Protection Group GEANT4 Workshop, ESTEC, 20-24, Sep. 1999 Evaluation of CAD status CAD Product:Suitability for G4 based application: n ProEngineer (Parametric)yes n Euclid (Matra Datavision)yes (with translator) n Catia (IBM Dassault)yes n MicroStation (Bentley)translator released ? n AutoCAD (AutoDesk)yes (R14.01 +) n I-deas (SDRC)yes It is not possible to use a CAD system to define and manage the material information as required in Geant4

7. Spacecraft Environment & Protection Group GEANT4 Workshop, ESTEC, 20-24, Sep. 1999 G4 STEP reader n Based on a free tool from NIST n Instantiate geometry in STEP file as G4LogicalVolumes n limitations : –accesses only geometry information, does not access the “management” information, i.e. the class 1 data. n How to associate material to each volume ? –To enhance the reader to read the class 1 information –temporary solution: use the sequential coincidence between volumes in step file and mga file.

8. Spacecraft Environment & Protection Group GEANT4 Workshop, ESTEC, 20-24, Sep. 1999 Front-end User Interface The Interface consists of n An off-the-shelf CAD system: for geometry modeling. The design is outputted in a STEP file. n The Material Generation & Association (MGA) tool: allow user to define the materials and associate them with volumes in the STEP file. The results are outputted in a MGA file. The STEP and MGA files will be used to define the geometry in a G4 application automatically.

9. Spacecraft Environment & Protection Group GEANT4 Workshop, ESTEC, 20-24, Sep. 1999 Requirement on STEP file format: AP 203 Volumes are named A description of material is desired. MGA file format: See the document: UoS-rep-05 G4 Application Using STEP & MGA Files

10. Spacecraft Environment & Protection Group GEANT4 Workshop, ESTEC, 20-24, Sep. 1999 MGA Design of the MGA tool is based largely on GGE: the G4 geometry editor.

11. Spacecraft Environment & Protection Group GEANT4 Workshop, ESTEC, 20-24, Sep. 1999 Future Work n Enhance the G4 STEP reader: compliance to AP203 class 1. n More tests with variuous types of STEP files from ESA, created by different CAD tools. n Integration of MGA/GGE? n Commit the proper G4mgareader to the G4 repository. n Documentation.

12. Spacecraft Environment & Protection Group GEANT4 Workshop, ESTEC, 20-24, Sep. 1999 Relevant Documents n G3 and CAD systems (UoS-rep-01) n GEANT4 and CAD systems (UoS-rep-02) Following documents can be found in DERA web pages: http://www.space.dera.gov.uk/space_env/geant_docs/geant_docs.html n URD CAD-Tool Front-End to GEANT4/SPARSET (UoS-rep-03) n Discussion Document on the General Design of the CAD Front End Tool (UoS-rep-04) n Development of GGE to perform materials and visualisation attribute definition in the CAD tool front end (UoS-rep-05) n SSD CAD Front End Tool for GEANT4/SPARSET (UoS-rep-06)