Hey guys, I really need some help and hopefully someone will be able to answer this. I have this npc I created on an island in Skyrim that continually bumps into the railing because the vanilla navmesh runs beneath the water. Now, my question is, can I actually alter that navmesh, or will it break Skyrim? And if so, is there something special I must do, such as not finalizing, etc to make it work correctly?

Any help would be great. I’m almost done with my mod, and am just trying to solve these small lingering problems.

Thanks,
-M.J.Kiely

MJ - you can modify the navmesh as long as your mod is an esp. You don't need to finalize as long as your changes don't affect other cells. If you get too close to the cell border and change the triangles that run up to the edge, you will need to finalize. If you make any change that affects a teleport door, you will need to finalize. It shouldn't break the game either way. If you make your mod an esm, changes you make to the navmesh will not work in the game.

I've edited many vanilla road navmeshes, actually HAD to edit them or my mod wouldn't work (ScenicCarriages.) There are a few threads you can read up on certain errors if you encounter them, but for a small section like that, I doubt you'll have much issue. I guess if you are not editing near a border and you make sure the borders are still finalized (make sure where the triangles meet still have the thick green borders) you could try not finalizing. The only drawback to finalizing that I am aware of is causing edit flags in the four adjecent cells. But since from what I have read on the forums (the many long long navmesh bug threads), navmeshes stack so I don't know if those edit flags cause a problem anyway. (I make a habit of finalizing all my edits though.)

When you are all done editing, I would check your work using the Check Navmesh button (Menu Navmesh | Select Triangle By Index | Check Navmesh), then if you have no errors, I would save your mod, again, checking for errors since some errors don't show up until you save then reload the mod, as other errors don't show up until you reload. Annoying. Then for the final test, check that your NPC's can get around in the cell and entering/leaving the cell. (This is all just standard "checking your work", imo.)

Wow, thank you both for the great replies. I've been banging my head for about two hours trying to maybe force him around it, and now I know I can just do what I initially planned and just remove the portion of navmesh. Thank you both.

You also might be able to just use a Primitive box, and set it to L_NAVCUT to simply cut out the navmesh your actor is trying to get to.

http://www.creationkit.com/Creating_Primitives

http://www.creationkit.com/Navmesh

Thanks Balok, but I've already gone through the above procedure considering how minor the cut was. But I will keep this in mind for future use.