KdTree.md added UI description

Author: haraldsteinlechner

docs/KdTrees.md

@@ -32,7 +32,8 @@ Recently i tried to make this quite robust, if however the cache file cannot be
 
 ## Create KdTrees for an OPC hierarchy.
 
-KdTrees can be constructed
- - directly from within PRo3D. This is now available via the UI.
+KdTrees can be constructed:
+ - directly from within PRo3D. This is now available via the UI
+ ![alt text](./images/createKdTree.png)
  - the [library](https://www.nuget.org/packages/OPCViewer.Base) and in [particular](https://github.com/aardvark-platform/OpcViewer/blob/7fdf368e1e59a2c33c0cc7e5ca3e20b8c18a42a0/src/OPCViewer.Base/KdTrees.fs#L307).
  - the OPC command-line tool. see [here](./OpcTool.md).