-Curvatures node for estimating curvatures on irregular meshes,
also known as surface differentials.

-This node ouputs a mixed scalar based on averaged curvatures,
it can be used as input in a Gradient node to get false colors.

-A preprocess is called by the node at first render, this could take
a long time with huge geometry.
-Remember that this prescan concerns all the geometry of the object, even if you are surfacing only a part of this object.
This preprocess is updated for each render if "After Deformation" is checked.

-Curvatures Node works with current geometry mesh, triangulated
polygons are not necessary and holes supported, but could fail with
degenerated polygon, (i.e duplicated vertices).

There is some issues with complex n-gon, not solved yet, so try to use
geometry mainly with triangles or quads.
-Layered object need different surface names to work properly with this node.




References :

-Based on Szymon Rusinkiewicz's algorithm.








-A Tension Node, output stretch and compression state of geometry.

-With two different ways for measuring tension, "Edge" or a better "Area" mode.

-For color mapping of Tension, simply connect the "Tension" in a gradient,
with colors ranged between -1.0 and 1.0 values.

-"Tension" output includes both negative compress and positive stretch values.
-"Stretch" output is the positive stretch value.
-"Compress" output is the positive compress value.

-Tension map can be slightly modified with "Damped" option .

-This node can also be used in Displacement node editor.

-Layered object need different surface names to work properly with this node.