void RTVector3::accelToQuaternion(RTQuaternion& qPose) const { RTVector3 normAccel = *this; RTVector3 vec; RTVector3 z(0, 0, 1.0); normAccel.normalize(); RTFLOAT angle = acos(RTVector3::dotProduct(z, normAccel)); RTVector3::crossProduct(normAccel, z, vec); vec.normalize(); qPose.fromAngleVector(angle, vec); }