Add note about the direction of rotation angles

glotzerlab · Oct 11, 2019 · 4d04b7f · 4d04b7f
1 parent 11469b7
commit 4d04b7f
Showing 1 changed file with 4 additions and 0 deletions.
diff --git a/rowan/functions.py b/rowan/functions.py
@@ -1047,6 +1047,8 @@ def to_matrix(q, require_unit=True):
 def from_axis_angle(axes, angles):
     R"""Find quaternions to rotate a specified angle about a specified axis.
 
+    All angles are assumed to be **counterclockwise** rotations about the axis.
+
     Args:
         axes ((...,3) np.array): An array of vectors (the axes).
         angles (float or (...,1) np.array): An array of angles in radians.
@@ -1081,6 +1083,8 @@ def from_axis_angle(axes, angles):
 def to_axis_angle(q):
     R"""Convert the quaternions in q to axis angle representations.
 
+    The output angles are **counterclockwise** rotations about the axis.
+
     Args:
         q ((...,4) np.array): An array of quaternions.