def _cone(self, axis, vector, limit=180, res=361, split=False): a = np.linspace(-limit, limit, res) x, y = l2xy(*v2l(rodrigues(axis, vector, a))) if split: dist = np.hypot(np.diff(x), np.diff(y)) ix = np.nonzero(dist > 1)[0] x = np.insert(x, ix + 1, np.nan) y = np.insert(y, ix + 1, np.nan) return x, y