# Quaternion Problem ( NI-Mate )

Hi,

I use an external program for the kinect, it gives me through OSC per limb the xyz position and wxyz rotation.

Little pseudo code:

// I got a OSC message and a Quaternion
oscMsg m;
ofQuaternion rot;

// Set the rotation of Quaternion to the data of the OSC message
// First 3 floats are xyz position, next is the degree(w), followed by 3 floats of xyz rotation
// Openframeworks declaration starts with xyz and ends with degree(w)
// NI-mate sends its degree(w) then its xyz
rot.set( m.getArgAsFloat(4), m.getArgAsFloat(5), m.getArgAsFloat(6), m.getArgAsFloat(3) );

ofVec3f axis;
float angle;

// Get angle and axis
rot.getRotate( angle, axis );

// Set angle and axis
ofRotate( angle, axis.x, axis.y, axis.z );

Does anyone have any clue whats going wrong? I’ve mixed up the sequence but with no luck, no correct rotation from limb to limb.

j

Maybe the argument is in radians and needs to be converted to degrees?

``````
rot.set( m.getArgAsFloat(4), m.getArgAsFloat(5), m.getArgAsFloat(6), m.getArgAsFloat(3)*RAD_TO_DEG );

``````

Nope, tried it, stopped rotating at all. Thanks though.

From the NI-Mate guys ( the application that gives me the OSC data ):

• Axis might be different, they have Y-up and Z-forward. That is what OF uses aswell.
• It might be a lefthanded system and we have a righthanded system

Quaternion(msg[4], -msg[6], msg[5], msg[3])

(xyz coordinates in the order msg[4], msg[6], msg[5] to switch z and y and “-msg[6]” to change from a left handed coordinate system to a right handed coordinate system)

…but no. I switched them around but it keeps Stevie Wondering on me