|Message: Boolean operatin problem (big problem)||Not Logged In (login)|
Click on the Forum title, e.g. on the "Forums by Category" page, to read a sequence of postings to the Forum and its threads all in one page. If you are only interested in one thread or the thread following a specific posting, click the thread or the posting, which takes you to a smaller page, which contains only the part you are interested in and may be easier to navigate.
Messages are "chained" if there are only replies at the first level, i.e. 1/1.html, 1/1/1.html etc. In case of "chained" messages the message number is replaced by the icon and there is no indentation.
Inline: Display the subject line only or also the text of the posting(s); for the choice "All" the "Outline" choices are switched off.
|1||0||1||no text / full text of posting|
|2||1||All||text for level 1 only / text for All postings|
Outline: Choose the depth of the posting thread, successive toggle controls provide increasing detail.
|1||2||1||2 levels / 1 level (original posting)|
|2||3||2||3 levels / 2 levels|
|3||3||All||3 levels / all levels (all postings)|
Actually I have a big problem with it. It seems to me when using union, intersection and subtraction boolean operations for construction geometry it often gives me such error:
ERROR: G4VSceneHandler::RequestPrimitives Polyhedron not available for irp_tp_nt1hhh. This means it cannot be visualized on most systems. Contact the Visualization Coordinator.
While I understand such error message is due to the shared surface or vertices between solids in the boolean operation, in most cases I do not have shared surfaces or vertices at all. Here is an example, in which I used union to put two trapezoid together. Then the united trapezoid is subtracted by a union solid (which is a box + two half cylinders). It all goes fine until I want to the final shape, which is a cylinder subtracted by this. The detailed code is shown below, please let me know whether it is due to the fact that GEANT4 can not handle so many boolean operations or something else? The weird thing is that I was able to contract such a shape in a smaller size. Thanks a lot.
// neutron beam tube 1: aluminum structure G4Trd* irp_tp_nt1aaa = new G4Trd("irp_tp_nt1aaa", 31.38*cm, 6.91*cm, 7.091*cm, 7.091*cm,50.0*cm); G4Trd* irp_tp_nt1bbb = new G4Trd("irp_tp_nt1bbb", 4.31*cm, 0.01*cm, 7.091*cm, 7.091*cm,51.48*cm); G4RotationMatrix* y1Rot= new G4RotationMatrix; y1Rot->rotateY(-13.75*degree); G4ThreeVector x5Trl(-19.14*cm,0.0,0.0); G4UnionSolid* irp_tp_nt1ddd = new G4UnionSolid("irp_tp_nt1ddd",irp_tp_nt1aaa, irp_tp_nt1bbb,y1Rot,x5Trl);
G4double irp_ct2_hh = 1.8*cm; G4double irp_ct2a1_r= 3.83*cm; G4double irp_ct2a2_hx=3.85*cm; G4double irp_ct2a2_hy=4.65*cm; G4double irp_ct2a2_hz=10.00*cm; // a dummy height G4Box* irp_ct2a_m= new G4Box("irp_ct2a_m",irp_ct2a2_hx,irp_ct2a2_hy,irp_ct2a2_hz); G4Tubs* irp_ct2a_l= new G4Tubs("irp_ct2a_l",0.0, irp_ct2a1_r,11.00*cm,0,2.0*pi); G4Tubs* irp_ct2a_r= new G4Tubs("irp_ct2a_r",0.0, irp_ct2a1_r,12.00*cm,0,2.0*pi); G4ThreeVector y3Trl(0.0,-4.65*cm,0.0); G4ThreeVector y5Trl(0.0,4.65*cm,0.0); G4UnionSolid* irp_ct2b = new G4UnionSolid("irp_ct2b",irp_ct2a_m,irp_ct2a_l,0,y3Trl); G4UnionSolid* irp_ct2d = new G4UnionSolid("irp_ct2d",irp_ct2b,irp_ct2a_r,0,y5Trl);
G4ThreeVector u(0, 1.0, 0); // cosine of x'/y'/z' and x G4ThreeVector v(0, 0, 1.0); G4ThreeVector w(1.0, 0, 0); G4RotationMatrix rotM1(u,v,w); G4ThreeVector z5Trl(0,0,52.98*cm); G4SubtractionSolid* irp_tp_nt1eee= new G4SubtractionSolid("irp_tp_nt1eee",irp_tp_nt1ddd,irp_ct2d,&rotM1,z5Trl); G4Tubs* irp_tp_nt1g = new G4Tubs("irp_tp_nt1g",0.0, IRP_r,36.0*cm,0.0,2.0*pi); G4IntersectionSolid* irp_tp_nt1hhh = new G4IntersectionSolid("irp_tp_nt1hhh",irp_tp_nt1g,irp_tp_nt1eee);
G4LogicalVolume* IRP_tp_nt1_Al_logicV = new G4LogicalVolume(irp_tp_nt1hhh, Al6061, "IRP_tp_nt1_Al_logicV"); G4VPhysicalVolume* IRP_tp_nt1_Al_physV = new G4PVPlacement(0, G4ThreeVector(0,0,200.0*cm), IRP_tp_nt1_Al_logicV, "IRP_tp_nt1_Al_physV", logicWorld, false, 0, checkOverlaps);
|Inline Depth:||Outline Depth:||Add message:|