You guys mean the Navmesh? I found it was not very difficult. Just tedious. I have a little text file I made with the steps I use:
CODE
www.creationkit.com/Bethesda_Tutorial_Navmesh
Select the cell you want to work on in the Cell View double click to bring it up in the Render Window.
Make sure nothing is selected in the Render Window (Press D to deselect all objects).
Open the Navmesh Toolbar Ctrl + E (On main toolbar between speech balloon and T).
Go to the main menu bar -> Navmesh -> Generation -> Recast-Based Generation.
The navmesh triangles are created. Now manually edit to add, remove, and move the triangles.
T toggles Triangle Selection On/Off
V toggles Vertex Selection On/Off
G toggles Edge Selection On/Off
R will delete a selected triangle/vertex.
Right Click to create a new vertex
Right Click + CTRL to select three vertexes, press A, and it creates a new triangle.
Once finished check to make sure there are no disconnected triangles. Press W (eye with shapes above and below) to see only the navmesh triangles.
Check for errors. Press CTRL + F, (red triangular flag icon). This brings up the Select Triangle window. Click on Check Navmesh.
Now automatically detect cover. Main toolbar -> Navmesh -> Find Cover
Finalize the Navmesh. (Red check mark in navmesh toolbar) A triangle near the door will turn green. This is necessary for NPCs to enter or leave.
I found the big part comes after creating the initial Navmesh, and then going in and cleaning it up. The CK tends to make a lot of little triangles, where a few large ones would do. It also has trouble going up and down staircases, and tends to just ignore them entirely. You only need two triangles to do an entire staircase. One with two points on the bottom of the stair, and the third point at one of the top corners, so you have a right triangle. The second triangle is a mirror of that, with two points at the top and the final one one bottom point to finish it out. You just have to wrap your head around making rectangular or square areas by sticking two right triangles together along the angle.
The hardest part for me was mastering the controls you need to use to add, remove, and edit the triangles. What often works best for me is to keep it on vertex selection. I select a single point of a triangle and then drag it to wherever I want. It also makes creating or linking new triangles easy. You just hold the Control key down, select three vertexes in a row, press A, and it creates a new triangle from the three points. I don't think I have it written down, but there is even a button you can push that will make everything but the navmesh itself invisible. That is very handy to use when you are finished, and want to check to see that everything is linked up.
Ooh, is this for path gridding? Thank you so much for this guidance! VERY Appreciated!
By the way, is there a way to prioritize paths in Skyrim? Everything I saw on googling was one color.