NavMesh tweaking

[Rick]

As you can see below the stairs and a large part of the top of the building aren't walkable by the navmesh. However with the player and the default character controller I'm able to walk up those stairs and get around on the building just fine. I feel like the parameters of the navmesh generation need to be tweaked to allow for more defined/tighter areas like these. All levels can't be big an blocky like HL.

 

 

[gamecreator]

I remember Aggror's pathfinding tutorial had at least one workaround to make the navmesh behave. It's pretty sensitive to tighter areas. And from your image, it could use some optimization too.

[flachdrache]

All levels can't be big an blocky like HL.

 

should not but must still ... you cant expect that random sticks and stones do give you a desired result i am afraid. Navmesh extractors aint that good (currently afaik). Thats an issue i had with eki one and tree models ... and clouds of navmesh in the leaves:d. Rather pointless to build AI without a final map if you ask me.

 

For "Le3" i think it would be good to suggest josh - to have a special material for CSG which can be used to block-out your level. Its nothing more then a collider for your AI agents at the end and details just slowing and bugging the navmesh extractor. Having ai-collider materials is what q3a uses for its area-awareness-system.

 

PS: not just an id fanboy - the terrain in my xna engine used a terrain processor with a virtual material ( no texture ) for its collision mesh too.

[Rick]

@flach You can make normal CSG and apply the invisible material to it and it'll do what you want. This is what I was doing for these buildings at first. However, it is a long and painful process to map out these buildings with CSG. It also has the same issues of surfaces needing to be bigger than you'd expect in order to get a navmesh on it. (Also there is a bug where if the CSG is a child of a model the navmesh won't be built on it. Without making the CSG a child your scene hierarchy gets pretty long) Those stairs in my picture are too narrow for the LE navmesh generator so it doesn't matter if I put it as CSG it'll never generate a path up them, yet the character controller for LE easily makes it up there with room to spare. I'd rather risk an AI getting stuck on something sometimes than not being able to go there at all. Hell, even in most AAA games the AI gets stuck on things sometimes.

[AggrorJorn]

Josh commented that the representation of the navmesh might not always be accurate to what it is actually there. Can you test if a character can walk on of the stairs?

 

Here is josh's comment:

You shouldn't need to place any special geometry. If the navmesh is continuous, it should work fine. It may intersect the stairs, but the AI will still work correctly.

Edited December 24, 2013 by Aggror

[Rick]

I'll give it a try later in the week. I'll be away from home for Christmas. This would sort of suck if that's the case as it makes it that much harder to test all areas of a scene and making tweaks wouldn't give an instant visual feedback making it very tedious to tweak & test. Thanks Aggror.

[Josh]

Given the space around the edges of the mesh, it appears your building is way too small. That looks like it should be scaled up two times or more.

[YouGroove]

@Rick :

Why not creating a low poly version that navmesh would be able to exploit and create walkable areas ?

Some sketchup low poly than tweak with high poly version

Or make a retopology of the high poly directly :

 

A solution would simply be able to modify/add polygons in some Navmesh mode :

Like add polygons where you want without any restriction ; this way you would make stairs walkable just by adding a big rectangle area etc ...

Or tell Navmesh tool to use some low poly collision model for generating navmesh.

[Rick]

When I'm in game the scale looks perfect to that character controller.

 

Yougroove, the generated shape file works fine. It's more about the size of the model.

[YouGroove]

You should be able to use any size model on a game you create, seeing the picture it is more some Navmesh scaling issue as Navmesh polygons are bigger than your house.

Why not proposing some scaling parameter in Navmesh tool ?

[cassius]

Ihad this problem.Sometimes re-building navmesh fixed it. Strange.