Docs: Clarify docs for BMesh methods

The previous docs for `normal_update` methods of `BMVert`, `BMEdge`,
`BMFace`, and `BMesh` were not clear on some behaviors.  These
behaviors are listed in D14370.  This commit updates the docs to be
clearer.

Reviewed By: Blendify

Differential Revision: https://developer.blender.org/D14370

1 files changed, 19 insertions, 4 deletions

diff --git a/source/blender/python/bmesh/bmesh_py_types.c b/source/blender/python/bmesh/bmesh_py_types.c
index baa2b0deb71..64cd59ea635 100644
--- a/source/blender/python/bmesh/bmesh_py_types.c
+++ b/source/blender/python/bmesh/bmesh_py_types.c
@@ -1262,7 +1262,12 @@ static PyObject *bpy_bmesh_select_flush(BPy_BMesh *self, PyObject *value)
 PyDoc_STRVAR(bpy_bmesh_normal_update_doc,
              ".. method:: normal_update()\n"
              "\n"
-             "   Update mesh normals.\n");
+             "   Update normals of mesh faces and verts.\n"
+             "\n"
+             "   .. note::\n"
+             "\n"
+             "      The normal of any vertex where :attr:`is_wire` is True will be a zero vector.\n");
+
 static PyObject *bpy_bmesh_normal_update(BPy_BMesh *self)
 {
   BPY_BM_CHECK_OBJ(self);
@@ -1611,7 +1616,12 @@ static PyObject *bpy_bmvert_calc_shell_factor(BPy_BMVert *self)
 PyDoc_STRVAR(bpy_bmvert_normal_update_doc,
              ".. method:: normal_update()\n"
              "\n"
-             "   Update vertex normal.\n");
+             "   Update vertex normal.\n"
+             "   This does not update the normals of adjoining faces.\n"
+             "\n"
+             "   .. note::\n"
+             "\n"
+             "      The vertex normal will be a zero vector if vertex :attr:`is_wire` is True.\n");
 static PyObject *bpy_bmvert_normal_update(BPy_BMVert *self)
 {
   BPY_BM_CHECK_OBJ(self);
@@ -1776,7 +1786,11 @@ static PyObject *bpy_bmedge_other_vert(BPy_BMEdge *self, BPy_BMVert *value)
 PyDoc_STRVAR(bpy_bmedge_normal_update_doc,
              ".. method:: normal_update()\n"
              "\n"
-             "   Update edges vertex normals.\n");
+             "   Update normals of all connected faces and the edge verts.\n"
+             "\n"
+             "   .. note::\n"
+             "\n"
+             "      The normal of edge vertex will be a zero vector if vertex :attr:`is_wire` is True.\n");
 static PyObject *bpy_bmedge_normal_update(BPy_BMEdge *self)
 {
   BPY_BM_CHECK_OBJ(self);
@@ -2012,7 +2026,8 @@ static PyObject *bpy_bmface_calc_center_bounds(BPy_BMFace *self)
 PyDoc_STRVAR(bpy_bmface_normal_update_doc,
              ".. method:: normal_update()\n"
              "\n"
-             "   Update face's normal.\n");
+             "   Update face normal based on the positions of the face verts.\n"
+             "   This does not update the normals of face verts.\n");
 static PyObject *bpy_bmface_normal_update(BPy_BMFace *self)
 {
   BPY_BM_CHECK_OBJ(self);