@Override
    public void write(JmeExporter ex) throws IOException {
        super.write(ex);
        OutputCapsule capsule = ex.getCapsule(this);
        capsule.write(radius, "radius", 0.5f);
    }
creates a SphereCollisionShape with the given radius

@param radius the desired radius (in unscaled units)
jme3-jbullet/src/main/java/com/jme3/bullet/collision/shapes/SphereCollisionShape.java