#include <GProp_PrincipalProps.hxx>
Public Member Functions | |
void * | operator new (size_t, void *anAddress) |
void * | operator new (size_t size) |
void | operator delete (void *anAddress) |
Standard_EXPORT | GProp_PrincipalProps () |
creates an undefined PrincipalProps. | |
Standard_EXPORT Standard_Boolean | HasSymmetryAxis () const |
returns true if the geometric system has an axis of symmetry. For comparing moments relative tolerance 1.e-10 is used. Usually it is enough for objects, restricted by faces with analitycal geometry. | |
Standard_EXPORT Standard_Boolean | HasSymmetryAxis (const Standard_Real aTol) const |
returns true if the geometric system has an axis of symmetry. aTol is relative tolerance for cheking equality of moments If aTol == 0, relative tolerance is ~ 1.e-16 (Epsilon(I)) | |
Standard_EXPORT Standard_Boolean | HasSymmetryPoint () const |
returns true if the geometric system has a point of symmetry. For comparing moments relative tolerance 1.e-10 is used. Usually it is enough for objects, restricted by faces with analitycal geometry. | |
Standard_EXPORT Standard_Boolean | HasSymmetryPoint (const Standard_Real aTol) const |
returns true if the geometric system has a point of symmetry. aTol is relative tolerance for cheking equality of moments If aTol == 0, relative tolerance is ~ 1.e-16 (Epsilon(I)) | |
Standard_EXPORT void | Moments (Standard_Real &Ixx, Standard_Real &Iyy, Standard_Real &Izz) const |
Ixx, Iyy and Izz return the principal moments of inertia in the current system. Notes : - If the current system has an axis of symmetry, two of the three values Ixx, Iyy and Izz are equal. They indicate which eigen vectors define an infinity of axes of principal inertia. - If the current system has a center of symmetry, Ixx, Iyy and Izz are equal. . | |
Standard_EXPORT const gp_Vec & | FirstAxisOfInertia () const |
returns the first axis of inertia. if the system has a point of symmetry there is an infinity of solutions. It is not possible to defines the three axis of inertia. | |
Standard_EXPORT const gp_Vec & | SecondAxisOfInertia () const |
returns the second axis of inertia. if the system has a point of symmetry or an axis of symmetry the second and the third axis of symmetry are undefined. | |
Standard_EXPORT const gp_Vec & | ThirdAxisOfInertia () const |
returns the third axis of inertia. This and the above functions return the first, second or third eigen vector of the matrix of inertia of the current system. The first, second and third principal axis of inertia pass through the center of mass of the current system. They are respectively parallel to these three eigen vectors. Note that: - If the current system has an axis of symmetry, any axis is an axis of principal inertia if it passes through the center of mass of the system, and runs parallel to a linear combination of the two eigen vectors of the matrix of inertia, corresponding to the two eigen values which are equal. If the current system has a center of symmetry, any axis passing through the center of mass of the system is an axis of principal inertia. Use the functions HasSymmetryAxis and HasSymmetryPoint to check these particular cases, where the returned eigen vectors define an infinity of principal axis of inertia. - The Moments function can be used to know which of the three eigen vectors corresponds to the two eigen values which are equal. if the system has a point of symmetry or an axis of symmetry the second and the third axis of symmetry are undefined. | |
Standard_EXPORT void | RadiusOfGyration (Standard_Real &Rxx, Standard_Real &Ryy, Standard_Real &Rzz) const |
Returns the principal radii of gyration Rxx, Ryy and Rzz are the radii of gyration of the current system about its three principal axes of inertia. Note that: - If the current system has an axis of symmetry, two of the three values Rxx, Ryy and Rzz are equal. - If the current system has a center of symmetry, Rxx, Ryy and Rzz are equal. . | |
Private Member Functions | |
Standard_EXPORT | GProp_PrincipalProps (const Standard_Real Ixx, const Standard_Real Iyy, const Standard_Real Izz, const Standard_Real Rxx, const Standard_Real Ryy, const Standard_Real Rzz, const gp_Vec &Vxx, const gp_Vec &Vyy, const gp_Vec &Vzz, const gp_Pnt &G) |
Private Attributes | |
Standard_Real | i1 |
Standard_Real | i2 |
Standard_Real | i3 |
Standard_Real | r1 |
Standard_Real | r2 |
Standard_Real | r3 |
gp_Vec | v1 |
gp_Vec | v2 |
gp_Vec | v3 |
gp_Pnt | g |
Friends | |
Standard_EXPORT GProp_PrincipalProps | GProp_GProps::PrincipalProperties () const |
Computes the principal properties of inertia of the current system. There is always a set of axes for which the products of inertia of a geometric system are equal to 0; i.e. the matrix of inertia of the system is diagonal. These axes are the principal axes of inertia. Their origin is coincident with the center of mass of the system. The associated moments are called the principal moments of inertia. This function computes the eigen values and the eigen vectors of the matrix of inertia of the system. Results are stored by using a presentation framework of principal properties of inertia (GProp_PrincipalProps object) which may be queried to access the value sought. . |
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