Rotate a vector by quaternion

[wandersonp]

Im trying to rotate a vector by quaternion but in houdini i got a weird angle

 

What I´m doing wrong?

 

GA_RWHandleV3 myNormal(gdp, GA_ATTRIB_POINT, "N");

 

GA_FOR_ALL_PTOFF(gdp, ptoff)

{
 

xform.identity();

xform.translate(0, 1, 0);

newpos = ph.get(ptoff) * xform;

quatRot.identity();

quatRot.assign(1.0, 0.0, 0.0, 0.125); // I think 0.125 mean 45º degree

quatRot.normalize();

 

myNormal.set(ptoff, quatRot.rotate(UT_Vector3(1, 0, 0)));

 

ph.set(ptoff, quatRot.rotate(newpos));

}

[wandersonp]

I made a mistake

 

the first parameter in Quaternion construction is the angle and the last 3 are the vector.

 

UTQuaternion vector(angle, x, y, z);

 

and works.