Houdini - Quaternions From Rotation and Axis
float deg = radians(@Frame % 360);
@orient = quaternion(set(deg, 0, 0));

Substituting set(0, deg, 0) - Y-axis.

Substituting set(0, 0, deg) - Z-axis.

float deg = radians(@Frame % 360);
@orient = quaternion(set(deg, 0, 0));

Substituting set(0, deg, 0) - Y-axis.

Substituting set(0, 0, deg) - Z-axis.
