In the G4/ROOT hierarchy there are In the G4/ROOT hierarchy there are three conceptual layers:three conceptual layers:

- G4VSolid: - G4VSolid: shape, sizeshape, size - G4LogicalVolume: - G4LogicalVolume: material, material, MF, sensitivity, MF, sensitivity, daughter volumes, etc.daughter volumes, etc. - G4VPhysicalVolume: - G4VPhysicalVolume: position position and rotation of and rotation of an instance of the logical an instance of the logical volume inside its mothervolume inside its mother

ExamplesExamples

CATIA-GDML Geometry BuilderCATIA-GDML Geometry Builder

IntroductionIntroduction

1- Institute for Theoretical and Experimental Physics (ITEP), Moscow, Russia1- Institute for Theoretical and Experimental Physics (ITEP), Moscow, Russia2- Bauman Moscow State Technical University, (BMSTU) Moscow, Russia2- Bauman Moscow State Technical University, (BMSTU) Moscow, Russia3- GSI - 3- GSI - Helmholtzzentrum für Schwerionenforschung GmbHHelmholtzzentrum für Schwerionenforschung GmbH , Darmstadt, Germany, Darmstadt, Germany

S. BelogurovS. Belogurov1,21,2(belogurov@itep.ru), Yu. Berchun(belogurov@itep.ru), Yu. Berchun22, A. Chernogorov, A. Chernogorov11, P. Malzacher, P. Malzacher33, , E. OvcharenkoE. Ovcharenko1,21,2, A. Semennikov, A. Semennikov11

CAD system

For mechanical, thermal, and some of electromagnetic For mechanical, thermal, and some of electromagnetic software the transfer is automated.software the transfer is automated. For radiation For radiation simulation packages that’s not a casesimulation packages that’s not a case..

In some cases automated geometry transfer is possible, but result is In some cases automated geometry transfer is possible, but result is not optimized for simulations and computations are too slow for big not optimized for simulations and computations are too slow for big assemblies and complex shapes.assemblies and complex shapes.

simulation tools

Design optimization of complex, densely packed Design optimization of complex, densely packed systems in severe radiation conditions (lke FAIR systems in severe radiation conditions (lke FAIR experiments) requires iterative exchange of geometry experiments) requires iterative exchange of geometry and material infoand material info

Geometry representation in CAD Geometry representation in CAD and G4/ROOT and G4/ROOT The difference is twofold: in the description of solid The difference is twofold: in the description of solid bodies and in the hierarchy of assemblies. bodies and in the hierarchy of assemblies.

The methodThe method

GLAD for R3BGLAD for R3B

Illustration of the procedure.Illustration of the procedure.a)a) Three Part files are loaded.Three Part files are loaded.b)b) Slice is twice inserted and positioned inside the CylinderSlice is twice inserted and positioned inside the Cylinderc)c) Cylinder is positioned inside the World (Box)Cylinder is positioned inside the World (Box)d)d) Geometry exported to GDML and read by ROOTGeometry exported to GDML and read by ROOT

Consists of 4 SS and Cu layers of complicated shapes with ribs.Consists of 4 SS and Cu layers of complicated shapes with ribs.All transferred to G4/ROOT. One of the shells is discussed hereAll transferred to G4/ROOT. One of the shells is discussed here

Cylinders, Tori, and Ellipsoids:Cylinders, Tori, and Ellipsoids:General shape is OK, but the shell has General shape is OK, but the shell has slits – bad for simulations slits – bad for simulations

Radii and heights of cylinders are Radii and heights of cylinders are modified, Ellipsoid -> Sphere, but no modified, Ellipsoid -> Sphere, but no slits: good for simulations slits: good for simulations

G4/ROOT-like representation G4/ROOT-like representation of a slice of CFC boxes and of a slice of CFC boxes and entire crystal arrayentire crystal array

General and partial views of General and partial views of the crystal array for R3B the crystal array for R3B calorimetercalorimeter

1. Implement G4 – like geometry in CATIA1. Implement G4 – like geometry in CATIA

2. Extend construction and measurement 2. Extend construction and measurement functionality of CATIA by special tools for functionality of CATIA by special tools for building G4 – like representation of the building G4 – like representation of the existing CAD modelexisting CAD model

3. Make simulation optimized geometry3. Make simulation optimized geometry

4. Exchange geometry via GDML4. Exchange geometry via GDML

Simple bodiesSimple bodies Crystal calorimeter for R3BCrystal calorimeter for R3B

The authors are grateful to Drs. F. Carminati, R. Brun, A. Gheata (CERN), The authors are grateful to Drs. F. Carminati, R. Brun, A. Gheata (CERN), and D. Bertini (GSI) for stimulating interest and discussions and to A. and D. Bertini (GSI) for stimulating interest and discussions and to A. Markin (BMSTU) for his contribution into the project. The work was Markin (BMSTU) for his contribution into the project. The work was supported by INTAS grant 06-1000012-8778supported by INTAS grant 06-1000012-8778 and by FAIR-Russia and by FAIR-Russia Recearch Center. Recearch Center.

PlansPlans

Required detalizationRequired detalization

Use material of mother volumesUse material of mother volumes

Avoid unionsAvoid unions

Md

dd

File structure for representation of a File structure for representation of a LogicalVolume.LogicalVolume.

PartBody PartBody contains a parameterized solid and contains a parameterized solid and material form G4Material CATIA catalog. material form G4Material CATIA catalog.

Unparameterized solid copy of the Unparameterized solid copy of the PartBodyPartBody is is published published

Solids, published in files corresponding to Solids, published in files corresponding to smaller smaller LogicalVolumes LogicalVolumes can be inserted into can be inserted into the tree with positioning. They represent the tree with positioning. They represent daughter volumes daughter volumes

Implementation of primitives as parameterized Implementation of primitives as parameterized User Defined Features (UDF) in CATIA. User Defined Features (UDF) in CATIA. The UDFs are placed into G4Catalog.The UDFs are placed into G4Catalog.For realization of Boolean combinations CATIA For realization of Boolean combinations CATIA operations operations Add, RemoveAdd, Remove and and IntersectIntersect are used. are used.

LHCb VELO read from LHCb VELO read from GDMLGDML

LHCb VELO CAD LHCb VELO CAD modelmodelRunning export MacroRunning export Macro

3 methods of multiple instantiation are implemented3 methods of multiple instantiation are implementedReplica - Replica - matches with matches with G4ReplicaVolG4ReplicaVolArray - Array - copied objects can be inserted into an copied objects can be inserted into an intermediate logical volumeintermediate logical volumeSimplePlacement Array - SimplePlacement Array - intermediate volume is only intermediate volume is only a convenient reference framea convenient reference frame

L1(Box1,Vacuum

L2(Box2, PlasticL2(Box2, PlasticL3(Cyl1,Cu)L3(Cyl1,Cu)

L4(Box3,Fe)L4(Box3,Fe)

,3L2)

, L3, 2L4), L3, 2L4)

In CAD hierarchy a minimal In CAD hierarchy a minimal unit is a solid body (unit is a solid body (part).part).

Products (assemblies) and Products (assemblies) and subproducts are only subproducts are only logical units – all the logical units – all the materials are assigned to materials are assigned to solid bodies inside the part solid bodies inside the part files or to partsfiles or to parts

Solids: CSG Solids: CSG vs. “arbitrary”vs. “arbitrary”

The problemThe problem The taskThe task

AcknowledgementsAcknowledgements- Enhancement of the set of implemented primitives- Enhancement of the set of implemented primitives- Improvement of the G4Materials catalog in CATIA- Improvement of the G4Materials catalog in CATIA- Implementation of checkers for CSG tree structure - Implementation of checkers for CSG tree structure

and volume and volume overlapsoverlaps- Adaptation of the CATIA Digital Mockup (DMU) - Adaptation of the CATIA Digital Mockup (DMU)

optimizer for optimizer for automatic fit of parameterized CSG models automatic fit of parameterized CSG models to existing partsto existing parts

- Case study and best practice elaboration- Case study and best practice elaboration