Hi all

Yet another question from me and hope some one shoots the answer immediately.. very simple though

I have been tryin to do a rigid body simulation ... things work fine until i hit a nan ..

What I am trying to do is retrieve a angle from a quaternion for which i wrote this following function...

Code:

				void get_AxisAngle_from_Quat(float &angle, Xlib::vec3d &axis) 

				{

					float squareLength = get4d_X()*get4d_X() + get4d_Y()*get4d_Y() + get4d_Z()*get4d_Z();

					
						

					if (squareLength>C_EPSILON)

					{

						angle = 2.0f * (float) acos(get4d_Z());
						//assert (!XlibMath::is__nan(angle));

						float inverseLength ;
						inverseLength = 1.0f /  (float) pow(squareLength, 0.5f) ;

						axis.x = get4d_X() * inverseLength;

						axis.y = get4d_Y() * inverseLength;

						axis.z = get4d_Z() * inverseLength;

					}

					else

					{

						angle = 0.0f;

						axis.x = 1.0f;

						axis.y = 0.0f;

						axis.z = 0.0f;

					}

				}
This is being refered in the code by this way
Code:
        Xlib::vec3d axis(1,0,0);
	float angle=0.0f;
	
	RBody[0].q.get_AxisAngle_from_Quat(angle,axis);
	
	Xlib::DevMsg("Quat  ",RBody[0].q);
	Xlib::DevMsg("Angle ", 	angle);
but This hits a nan and everytime it hits nan my object disappears from the screen.... (DevMsg is a overload for cout i use) When i try printing out the values at the point where i hit the nan this shows this

Code:
DevMsg: Quat   1.442195 0.698514 1.700220 0.403262
Angle  nan
I read online but it states nan is got by dividing by 0 .. but clearly i am not using any divisions at al...

can someone clarify me on where i went wrong ????

Cheers and regards