SSE Navmesh for exterior cells?

[Wolfstorm]

There are three methods for navmesh generation: object-based, havok-based and recast-based.

Which one is best for navmesh generation in a exterior cell?

 

If I hit to generate will it generate for the entire worldspace, or just the cell the pointer is currently in?

Is it possible to restrict it to a few cells? Could I use collision planes to define this area?

 

I checked in the tutorials but didnt find a answer to these questions.

[cumbrianlad]

In all honesty, and I know this depends on how many cells we're talking about, but even in exteriors, I prefer to navmesh by hand... then again, I'm one of those freakish people who actually enjoy navmeshing! (Don't forward this post to my psychiatrist, please: he's got enough work as it is). :sick:

 

I have tinkered with auto navmesh but found myself more frustrated correcting the mess it generally seemed to make, than simply plodding through one triangle after another.

 

The tutorials are very vague on the subject, i agree. If someone could answer this to say which settings work great, I may even forgoe my guilty navmeshing pleasure. I suspect that the reason nobody has made such a tutorial after 10 years is that the Nirvana of one-click Navmeshing in the 'Frustration Kit', has never been found.

 

It's over to the Gurus to answer you more precisely. I'd be more than happy to share the tips I've amassed about manual Navmesh techniques, though.

[Wolfstorm]

I started with navmesh yesterday, for a cave I'm making, and found out the self-generated one (which the tutorial recommends to be recast-based) was very buggy. So I made everything by hand. I quite enjoyed it, too, as I just needed to turn the camera, select the three points and press A.

 

But for exteriors, it would take too much time, as there is too much terrain to cover.

I found out that havok-based seemed to work better for the exteriors, with the "height map only" option selected. Still, it have put navmeshes on top of roofs: https://imgur.com/QlhjlsK

I also found out it does one operation per cell, not the whole map.

Edited February 2, 2020 by Wolfstorm

[cumbrianlad]

Yeah, now that you mention it, I should have remembered about one cell only. It doesn't at all surprise me that it navmeshes roofs, rocks and everything else that can't be navigated by, except a player using the sideways jump move. That's why I never trust it!

 

How many cells? I've navmeshed a worldspace of 40+ cells and it 'only' took a couple of days!

 

Water is a 'B***h' but take note of the water height, navmesh to the edge of it, then set the water height for the worldspace a few hundred below and navmesh the water, change it to 'water', restore the settings and carry on*. Another one (manula only), 'Ctrl T' to toggle trees off before navmeshing, '8' to toggle grass off. That way you're just left with the terrain. and the navmesh node doesn't 'jump'three miles above where you think it should be placed!

 

Honestly, I don't find it takes too much time... but I'm very patient!

 

* the same applies in interiors. hiding the water doesn't work... the navmesh always jumps to the water surface. Drag the water down after navmeshing to the edge, do the underwater navmesh, mark it as water and move the water back up. Ignore tutorials that say you have to drag each water node down... a complete waste of time.

[Wolfstorm]

Thanks for pointing out about the water, because I made the navmesh (for the cave) in the surface of the water (there is a big hole with water at some point, with a passage near its surface). I didnt know I had to drag the water down.

 

How do you do with drawbridges? I made the navmesh in the air for a drawbridge. I copied the bridge, put it in the position were it would be draw, made the navmesh over it, then deleted the copy. I didnt tested it yet.

Edited February 3, 2020 by Wolfstorm

[thumbincubation]

Cumbrian, I've been very hesitant to attempt outdoor navmesh, even after seeing the youtube tutorial on how to select portions and reassign it, before deletion. I would much rather delete an entire cell and redo it, but I can't understand what little I've been able to find about connecting to other cells and those green lines. Would you be willing to do a mini tutorial about exterior? I'd be forever grateful. So many things I've wanted to do outside.

[cumbrianlad]

Hi.

 

Sorry for the delay. I've had one heck of a lot going on recently.

 

Drawbridges: I ought to have mentioned in my manual navmesh tips that the first rule, for interior or exterior cells is to work from the highest point down! If you don't, you keep on picking the nearest node that is somewhere below in the render window.

 

I'm guessing, Wolfstorm, that you mention drawbridges, not for navmeshing them, but because they are sometimes raised and then lowered, so do you navmesh or not?. The answer is that you navmesh them normally and then stick a collision cube around them. Set the collision cube's property to L_Navcut. This means that the navmesh over the bridge is ignored by NPCs, so they won't cross it and fall in the water/lava or whatever is under the bridge. When the bridge is raised/lowered a script enables/disables the collision cube so the navmesh can be used by NPCs. This is exactly how Bethesda did the magic walkways in the DLC2 quest with the scholar from the Skaal village.

 

Thumbincubation, I feel hesitant to offer what I've learned by trial and error to one with so much experience! Since I love navmeshing, though, I may try to get over my reticence and post a tutorial.

 

What I've found is that Bethesda's own navmesh is crap in a lot of cases. This is why NPCs and followers get stuck at little objects. Looking at their own exterior navmesh is no great guide until you realise this. If I did a guide, it would be for perfectionists who wanted it to be ideal. I can only tell you what I do about the cell borders and this probably only applies to hand navmesh...

 

... First, I select the entire vanilla navmesh using flood-fill, use ctrl to select any relevant islands. Then I drag the whole lot down using the 'z' tool. Next, with the vanilla navmeshes still selected, I hit the 'H' key to hide them and stop them being selected.

 

I then navmesh to the edges of the cell, but not too close. (Maybe a foot or so [o.3 m] away from the edge). I put points close to where there is a node in the neighbouring vanilla cell, because we need to link up to every vanilla node on the cell borders. It's easier if you don't put your node very close to the vanilla node because you need to be able to select your node later.

 

Once the cell is navmeshed, I just move around the cell border, from one node to another. I select my navmesh node and move it until it is lined up with the vanilla node (even if the vanilla node is wrong!) Then check navmesh, fnd cover edges and finalize. I end up with all green borders.

 

When you are moving each of your own nodes, you may need to toggle between visibility modes for navmesh. That helps to get the height of the node right. After that just push it until it matches up.

[thumbincubation]

This is awesome. Thank you. I will give it a try. Do you delete the original after you have pulled it down, or leave it in place?

[c0ax599]

This really really helped me. It took me awhile to "find" this tut, but eventually i did. At that time I had no hope of releasing my mod. This works.

Skyrim Creation Kit Tutorial: Editing Exterior Navmesh correctly

 

I've only got one mod so far out there. And my outdoor navmesh was totally hosed. I deleted some vanilla navmeshes, AND my house was covering 2 cells. Not good. 2 cells can be done, but I'm never doing it again.. ;)

 

I had to use SSEEdit (thanks to help from those guys on the xedit discord too!) to restore my deleted navmeshes. And I had to select every piece of my house, and move it into one cell.

Then I followed this tutorial to the T. As a result, I have a working exterior navmesh and a released mod.

 

I had to watch that tutorial vid a few times, and follow it while doing it the final time (watching, pausing, doing, repeat). But it works!

 

Good luck.

c0AX

[Wolfstorm]

Drawbridges: I ought to have mentioned in my manual navmesh tips that the first rule, for interior or exterior cells is to work from the highest point down! If you don't, you keep on picking the nearest node that is somewhere below in the render window.

 

I'm guessing, Wolfstorm, that you mention drawbridges, not for navmeshing them, but because they are sometimes raised and then lowered, so do you navmesh or not?. The answer is that you navmesh them normally and then stick a collision cube around them. Set the collision cube's property to L_Navcut. This means that the navmesh over the bridge is ignored by NPCs, so they won't cross it and fall in the water/lava or whatever is under the bridge. When the bridge is raised/lowered a script enables/disables the collision cube so the navmesh can be used by NPCs. This is exactly how Bethesda did the magic walkways in the DLC2 quest with the scholar from the Skaal village.

 

 

I've made the navmesh over the pit, using the bridge as a guide.

 

 

Then I put the bridge in a raised position (using localtrans), which is the position it will be initially. The activator is a lever, very far from there, in another part of the cave.

 

 

I put the collision box around it and found the L_NAVCUT in the primitives section. I never used it, so I dont know if its right. Should I mark "player activator"?

The dwemer bridge is called DweRetractableBridge01NONAVCUT, its the only dwemer bridge I found in the Activator section.

 

How the npcs will know where the hole starts? Because the collision cube is cutting the navmesh in the other side of the bridge, but that is the end part of the dungeon. The npcs will come from left to right in the screenshots above.

 

Should I do the navmesh in the bridge, while it is raised? Do the navmesh moves with the bridge, when it is activated?

Edited February 9, 2020 by Wolfstorm