protected void createShape() {
        cShape = new SphereShape(radius);
        cShape.setLocalScaling(Converter.convert(getScale()));
        cShape.setMargin(margin);
    }
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