[Bf-docboard-svn] bf-manual: [8876] trunk/blender_docs/manual/modeling/geometry_nodes/input/input_index.rst: Geometry Nodes: Add note about index consistency

[Hans Goudey]

Revision: 8876
          https://developer.blender.org/rBM8876
Author:   HooglyBoogly
Date:     2022-01-26 05:45:57 +0100 (Wed, 26 Jan 2022)
Log Message:
-----------
Geometry Nodes: Add note about index consistency

Modified Paths:
--------------
    trunk/blender_docs/manual/modeling/geometry_nodes/input/input_index.rst

Modified: trunk/blender_docs/manual/modeling/geometry_nodes/input/input_index.rst
===================================================================
--- trunk/blender_docs/manual/modeling/geometry_nodes/input/input_index.rst	2022-01-25 23:35:32 UTC (rev 8875)
+++ trunk/blender_docs/manual/modeling/geometry_nodes/input/input_index.rst	2022-01-26 04:45:57 UTC (rev 8876)
@@ -15,7 +15,18 @@
 visible in the 3D Viewport. However, the index value is visible in the left-most column in
 the :doc:`Spreadsheet Editor </editors/spreadsheet>`.
 
+.. note::
+   
+   Indices in geometry data are often defined by the internals of complex algorithms that creat it.
+   If no inputs change, indices will be the same when the same node tree is executed multiple times.
+   However, they may not be predictable when inputs to nodes that generate geometry or change its
+   topology are adjusted. Additionally, updates to geometry processing algorithms in newer versions
+   of Blender may change the order of generated elements.
 
+   To avoid relying on consistent indices, it is recommended to calculate them locally,
+   or to avoid operations that change topology when they must be consistent over time.
+
+
 Inputs
 ======