2. Interface between Root and CAD Peter Biryukov (p.biryukov@gsi.de)

3. Aim The aim of the project is an interplay between CAD systems and the detector description used by the physics simulation software. The work is mainly focused on the needs of GSI

4. Earlier Attempts The work with related aim was performed in the end of the previous century in CERN Name of the project: The Computer Aided Detector Design (CADD) People: Mik Ferran, Nils Høimyr, Jouko Vuoskoski, and others. Web Page: http://cadd.web.cern.ch/cadd/http://cadd.web.cern.ch/cadd/ Programs: CADINT CADINT The CADINT interface allows one to export detector models from GEANT to SET format. PROGEANT PROGEANT PROGEANT allows one to exchange detector geometry between GEANT and 3D-PSM, a CAD system from ItalCAD. PROGEANT is a bi-directional interface. EUGENIE EUGENIE EUGENIE allows one to exchange detector geometry between GEANT and EUCLID. EUGENIE is a bi-directional interface. GESTEP GESTEP GESTEP is an utility program for GEANT detector models and was implemented in order to establish a framework for the future standard, STEP, and for object-oriented techniques.STEP CADGE CADGE CADGE is an interface application to transfer GEANT detector models to CAD system using the new STEP standard.STEP

5. Main differences NewOld Geometry is from Root (and Geant4) Geant3 CAD CATIAAutoCAD Exchange file format STEP (and probably some custom format) Several formats including STEP in late programs

6. The problems solids are represented by a number of vertexes, edges, surfaces, etc... solids are represented by a number of vertexes, edges, surfaces, etc... no hierarchy no hierarchy there are several pre- defined solids with a possibility to change some of their parameters (such as height of tube for example) there are several pre- defined solids with a possibility to change some of their parameters (such as height of tube for example) hierarchy hierarchy The main problem is the different representation of solids in CAD systems and in the physics simulation software. CAD ROOT/Geant4

7. Possible solutions To make a conversion between Root and CAD representation of solids To make a conversion between Root and CAD representation of solids provides an opportunity to use powerful CAD systems to design geometry for simulation provides an opportunity to use powerful CAD systems to design geometry for simulation is very difficult (if even possible) to implement (in particular the problem in conversion from CAD to Root) is very difficult (if even possible) to implement (in particular the problem in conversion from CAD to Root) To restrict CAD to produce only limited set of solids supported by Root/Geant4 To restrict CAD to produce only limited set of solids supported by Root/Geant4 Allows to use CAD to create geometry for simulation Allows to use CAD to create geometry for simulation Makes users to use CAD in unusual way. Makes users to use CAD in unusual way.

8. Implementation Linux, C++ Linux, C++ Open CASCADE () Open CASCADE (http://opencascade.org/)http://opencascade.org/ Root/Geant4 Root/Geant4 STEP STEP Conversion between Root and CAD representation of solids http://www-hades.gsi.de/~biryukov/CADD/ Open CASCADE Technology is software development platform freely available in open source. It includes components for 3D surface and solid modeling, visualization, data exchange and rapid application development.software development platform STEPSTEP is the ISO STandard for the Exchange of Product data (ISO-10303)ISO STEP is an evolving standard which covers the whole Product Life Cycle in terms of data sharing, storage and exchange. STEP is replacing other exchange standards like IGES, DXF, SET and VDAFS, as well as allows for complete descriptions in electronic form of all data related to Manufacturable Products.

9. Implementation Restrict CAD to produce only limited set of solids Linux, C++ Linux, C++ CATIA (and its build in Visual Basic) CATIA (and its build in Visual Basic) Root/Geant4 Root/Geant4 custom, STEP-like file format custom, STEP-like file format

10. Implementation Restrict CAD to produce only limited set of solids Linux, C++ Linux, C++ CATIA (and its build in Visual Basic) CATIA (and its build in Visual Basic) Root/Geant4 Root/Geant4 custom, STEP-like file format custom, STEP-like file format The future plans are : Saving/Loading files into CATIA Root/Geant4 Boolean solids The End