There is the Tgeo interface of root that does that

http://root.cern.ch/drupal/content/geometry-definition-navigation

You can look into the manual

In GEANT4 you can use the Boolean operations to get the shapes as in your Figure. Sum, difference etc. of the simple solid figures is the best way to obtain the complicated shapes.

this is an example please see it I can help later

//----------------------------- Detector -------------

G4double hightOfTheCore = 41.00*mm;

G4double hightOfTheDeadL = 0.03*mm;

// The crystal and the core are considred to be two concentric cylinders filled with germanium minus the cylinder constituting the dead layer which will be added to th core and the crystal volumes (see below)...

//------------------------------ crystal volume-----

G4double innerRadiusOfTheTube = 0.0*mm;

G4double outerRadiusOfTheTube = 27.0*mm;

hightOfTheTube = (55.0-hightOfTheCore-hightOfTheDeadL)*mm;

G4double startAngleOfTheTube = 0.*deg;

G4double spanningAngleOfTheTube = 360.*deg;

G4Tubs* tracker_tube = new G4Tubs("tracker_tube",innerRadiusOfTheTube,

outerRadiusOfTheTube,hightOfTheTube/2.,

startAngleOfTheTube,spanningAngleOfTheTube);

tracker_log = new G4LogicalVolume(tracker_tube,HPGe,"tracker_log",0,0,0);

G4double trackerPos_x = 0.0*m;

G4double trackerPos_y = 0.*m;

G4double trackerPos_z = (hightOfTheTube/2.+hightOfTheCore)*mm;

tracker_phys = new G4PVPlacement(0,

G4ThreeVector(trackerPos_x,trackerPos_y,trackerPos_z),

tracker_log,"tracker",experimentalHall_log,false,0);

//------core volume---------------------------

G4double innerRadiusOfTheCore = 8.7/2.*mm;

G4double outerRadiusOfTheCore = 27.0*mm;

G4double startAngleOfTheCore = 0.*deg;

G4double spanningAngleOfTheCore = 360.*deg;

G4Tubs* Core_tube = new G4Tubs("Core_tube",innerRadiusOfTheCore,

outerRadiusOfTheCore,hightOfTheCore/2.,

startAngleOfTheCore,spanningAngleOfTheCore);

Core_log = new G4LogicalVolume(Core_tube,HPGe,"Core_log",0,0,0);

G4double CorePos_x = 0.0*mm;

G4double CorePos_y = 0.0*mm;

G4double CorePos_z = (hightOfTheCore/2.0)*mm;

Core_phys = new G4PVPlacement(0,

G4ThreeVector(CorePos_x,CorePos_y,CorePos_z),

Core_log ,"tracker",experimentalHall_log,false,0);

//------------------------------ dead layer volume placed above the crystal volume----------

G4double innerRadiusOfTheDeadL = 0.*mm;

G4double outerRadiusOfTheDeadL = 27.0*mm;

G4Tubs* tracker_dead = new G4Tubs("tracker_dead",innerRadiusOfTheDeadL,

outerRadiusOfTheDeadL,hightOfTheDeadL/2.0,

startAngleOfTheTube,spanningAngleOfTheTube);

dead_log = new G4LogicalVolume(tracker_dead,HPGe,"tracker_log",0,0,0);

G4double deadPos_z = (hightOfTheCore+hightOfTheTube+hightOfTheDeadL/2.)*mm;

dead_phys = new G4PVPlacement(0,

G4ThreeVector(trackerPos_x,trackerPos_y,deadPos_z),

dead_log,"dead",experimentalHall_log,false,0);

//----------Beriulium volume----------------------------------------------------

// This the window of the detector------

G4double innerRadiusOfTheAl = 0.0*mm;

G4double outerRadiusOfTheAl = 27.0*mm;

hightOfTheAl = 0.50*mm;

G4Tubs* tracker_Al = new G4Tubs("tracker_al",innerRadiusOfTheAl,

outerRadiusOfTheAl,hightOfTheAl/2.,

startAngleOfTheTube,spanningAngleOfTheTube);

Be_log = new G4LogicalVolume(tracker_Al,Be,"Be",0,0,0);

G4double AlPos_z = (hightOfTheCore + hightOfTheTube + hightOfTheDeadL + 7.4 - hightOfTheAl/2.0)*mm;

Al_phys = new G4PVPlacement(0,

G4ThreeVector(trackerPos_x,trackerPos_y,AlPos_z),

Be_log,"alum",experimentalHall_log,false,0);

G4cout

To Wissam Zaidan

I have running your programme. But that was not the tapper shape geometry which i have already attached in my question. I want tapper shape geometry. I have attached the geometry according to your code. I have also attached the "DetectorConstruction.cc" programme. You can run the given programme and you can see the geometry which is attached here. I request you to help me.

To Wissam Zaidan

Here the geometry according to your code.

Please ask this question directly in the Geant4 User Forum using the geometry category, http://hypernews.slac.stanford.edu/HyperNews/geant4/get/geometry.html

Firstly, there are many different "Clover" detectors (EXOGAM, EUROGAM, TIGRES, ANL, GIRFIN etc etc)

Here is the geometry for a EUROGAM Phase-II.

(first the .hh)

Now the .cc

You'll also need this (my materials definitions):

In your detector construction (cc) you'll need to add:

#include "Clover.hh"

and to actually construct it you'll need to add:

PhaseII* aDetector = new Clover();

aDetector->SetPosition(G4ThreeVector(0.*mm, 0.*mm, 0.*mm));

G4RotationMatrix rotMat;

rotMat.set(0,0,0);

rotMat.invert();

aDetector->SetRotation(rotMat);

aDetector->Placement(0, physiWorld);