rotation to unit vector

I've already done this the long way, but is there a simple way to turn a rotation into a unit vector describing the direction an object is pointing ?

As it happens I'm only concerned about the z axis rotation as it gives me a heading for an object travelling only in the x,y plane, if that makes it easier.

My current method is as follows:

rotation myRot = llGetRot();
vector myEulerRot = llRot2Euler(myRot);
float myHeading = myEulerRot.z;
float myXcomponent = llCos(myHeading);
float myYcomponent = llSin(myHeading);
myUnitVector = <myXcomponent,myYcomponent,0>

I just thought a 1 line vector/rotation math expression might do the same thing...

I have half an idea quaternions actually work something like this anyway.

Thanks in advance to any maths people who can help !

llRot2Fwd(the_rotation); will return a unit vector pointing forward of the given rotation There are also llRot2Up and llRot2Left.

If you just need a global-Z orientation, then get the llRot2Fwd vector, put 0 as its z component and use the norm of this new vector

vector temporary = llRot2Fwd(llGetRot());
temporary.z = 0.0;
vector my_unit_vector = llVecNorm(temporary);

thanks very much ! it's so obvious now you point it out