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SIRotation

Object Hierarchy | Related C++ Class: CRotation

Description

This object represents a rotation in 3D space. It supports three representation methods: X, Y and Z Euler angles, Quaternion and 3 by 3 matrix.

Note: When represented as X,Y,Z Euler angles the values are always in Radians, not degrees.

Methods

Properties

Examples

JScript Example

/*
   Demonstrates different representations of a rotation: 

   -As a SIRotation object
   -As a 3x3 matrix
   -As a 4x4 matrix
   -As a SITransformation object
   -As a SIVector3 object
*/

var oSIRotation = XSIMath.CreateRotation( 
              XSIMath.DegreesToRadians( 45 ),
              XSIMath.DegreesToRadians( 30 ),
              XSIMath.DegreesToRadians( 15 ) ) ;

oSIMatrix3 = XSIMath.CreateMatrix3() ;
oSIRotation.GetMatrix3( oSIMatrix3 ) ;

oSIMatrix4 = ConvertMatrix3ToMatrix4( oSIMatrix3 ) ;

oSITransformation = XSIMath.CreateTransform() ;
oSITransformation.SetMatrix4( oSIMatrix4 ) ;

var oSIVector3 = XSIMath.CreateVector3() ;

oSITransformation.GetRotationXYZAngles( oSIVector3 ) ;

// Prove that we haven't lost the original rotation values
Application.LogMessage( "Rotation " + 
          XSIMath.RadiansToDegrees( oSIVector3.X ) + ", " +
          XSIMath.RadiansToDegrees( oSIVector3.Y ) + ", " +
          XSIMath.RadiansToDegrees( oSIVector3.Z ) ) ;

// Output (notice very small rounding problems that occur
// when dealing with pi and trig functions):
//INFO : Rotation 45, 29.999999999999996, 14.999999999999998

function ConvertMatrix3ToMatrix4( oM3 )
{
   // Helper function to convert 3x3 rotation matrix
   // to equivalent 4x4 transformation matrix:
   //
   // r11 r12 r13 0
   // r21 r22 r23 0
   // r31 r32 r33 0
   // 0   0    0  1

   oSIMatrix4 = XSIMath.CreateMatrix4(
       oM3(0,0), oM3(0,1), oM3(0,2), 0,
       oM3(1,0), oM3(1,1), oM3(1,2), 0,
       oM3(2,0), oM3(2,1), oM3(2,2), 0,
       0,        0,        0,        1 ) ;

   return oSIMatrix4 ;
       }

See Also

Autodesk Softimage v7.5     <     >