0023247: Wrong value for StaticMoments in GProp_GProps

View Issue Details [ Jump to Notes ]

[ Issue History ] [ Print ]

Project

Category

View Status

Date Submitted

Last Update

0023247

Community

[OCCT] OCCT:Modeling Algorithms

public

2012-07-05 18:00

2012-07-05 18:01

Reporter

Jerome Monaco

Assigned To

jgv

Priority

normal

Severity

minor

Status

new

Resolution

open

Platform

Windows

VC++ 2010

OS Version

32 bit

Product Version

[OCCT] 6.5.2

Target Version

Fixed in Version

Summary

0023247: Wrong value for StaticMoments in GProp_GProps

Description

The StaticMoments function does not compute the static moments correctly, and wrong values are returned.

Steps To Reproduce

  /// Build rectangle face
  //----------------------
  double dx( 10.0 );
  double dy( 5.0 );

  BRepBuilderAPI_MakePolygon MP;
  MP.Add( gp::Origin() );
  MP.Add( gp_Pnt( dx, 0.0, 0.0 ) );
  MP.Add( gp_Pnt( dx, dy, 0.0 ) );
  MP.Add( gp_Pnt( 0.0, dy, 0.0 ) );
  MP.Close();
  MP.Build();

  TopoDS_Face f = BRepBuilderAPI_MakeFace( MP.Wire() );

  /// Compute face properties
  //-------------------------
  GProp_GProps sp( gp::Origin() );
  BRepGProp::SurfaceProperties( f, sp );

  double SMx, SMy, SMz;
  sp.StaticMoments( SMx, SMy, SMz );

  /// Rectangle center of gravity
  //-----------------------------
  double xG( dx / 2.0 );
  double yG( dy / 2.0 );

  /// Rectangle area
  //----------------
  double a( dx * dy );

  /// Correct values for Ix, Iy and Iz
  //----------------------------------
  double SMxGood( a * yG );
  double SMGood( a * xG );
  double SMzGood( a * 0.0 );

Issue History
Date Modified	Username	Field	Change
2012-07-05 18:00	Jerome Monaco	New Issue
2012-07-05 18:00	Jerome Monaco	Assigned To	=> jgv

Relationships

Notes
There are no notes attached to this issue.