wrong Taylor's expansions in 'integrateTransform'

[Ethan]

in bullet 2.7.7, file src\LinearMath\btTransformUtil.h, line 66

is:

Code: Select all

		if ( fAngle < btScalar(0.001) )
		{
			// use Taylor's expansions of sync function
			axis   = angvel*( btScalar(0.5)*timeStep-(timeStep*timeStep*timeStep)*(btScalar(0.020833333333))*fAngle*fAngle );
		}

should be

Code: Select all

		if ( fAngle < btScalar(0.001) )
		{
			// use Taylor's expansions of sync function
			axis   = angvel*( btScalar(0.5)*timeStep+(timeStep*timeStep*timeStep)*(btScalar(0.020833333333))*fAngle*fAngle );
		}

not '-' but '+'

[Ethan]

forget it, bullet is correct, the paper "Practical Parameterization of Rotations Using the Exponential Map", F. Sebastian Grassia bullet referred is wrong