How to make the ground follow my skewed-angled walls Created 3 years ago2021-07-16 02:04:46 UTC by Pezus

Hey everyone, so, if you don't get what I mean with the title, let me explain.
So, I've been working in this cs 1.6 map for quite some time now, and I encountered this problem a few months ago and I came up with a decent solution for it. The problem is, as the title indicates, making the ground follow my wall's angles. The solution that I came up with is just clipping the ground following the wall's vertices. This worked really nicely but it's very tedious, and it has 2 flaws:
1- It's extremely tedious to do this each time that I edit the wall's angles or whatever, I have to delete the ground of the part that I'm working on and just re-do it from scratch. Want to change this part's walls? no problem but remember that you have to delete the ground, add the brush and clip it again.
2- The compiler isn't very happy with it, it's better than other very bad solution that I tried but it recently started giving me "Ambiguous Leafnode Content" warnings.
And not to mention that I have the same problem for the sky, I just make a copy of the ground, move it to sky level and just apply the sky texture to it.
I've tried decompiling some already existing maps but it didn't help at all.
Somebody with mapping experience please help me, I would really appreciate if someone can give me a proper solution to my problem, I'm tired of having to clip the ground from 0 just because I changed a wall's angle a little bit.
Edit: Added the imgur link since img: is not working: https://imgur.com/a/ch23R89

You don't need to do this. The compile tools will combine all world brushes into a single mesh and will remove any faces on the outside, so it's no problem if brushes are sticking out. That's also why decompiling gives such poor results: there's just not enough information in a bsp file to reconstruct the original brushwork.

1. If you really want to, you can use the vertex manipulation tool (Shift + V) to move the corners of your floor brush around. This mode also lets you create new edges (by selecting two existing vertices (white) or edges (yellow) and pressing Ctrl + F, or merge vertices by dragging them on top of each other. This is an advanced tool however, and using it incorrectly can produce invalid brushes, so use with care.

2. Judging from your screenshot, I can't tell whether you've got brushes with off-grid vertices, but you do have several points where the corners of two brushes join up next to the edge of another brush. That may result in tiny cracks between brushes, which is probably what's causing this 'ambiguous leaf node' error. That's one reason why I'd recommend sticking to a coarser grid size when working with 'structural' brushwork like this, and to stick to 'safe' slopes like 1:2, 1:4, etc, as that makes it easier to ensure that junction points like that are still perfectly aligned with the grid.

So can I just use a giant single mesh for all of the ground?
Edit: No, there aren't any small cracks in the floor, since they follow the walls perfectly there aren't any

I wouldn't ever go as far as a giant plane floor, but yeah you shouldn't have issues with the floor extending out into the void if it's becoming a hassle.

You certainly don't need to delete and re-clip the floor any time you ever change the walls - Vertex manipulation will let you reposition any of the floor's vertices to match the new wall brushwork. The areas that Cap'n P is pointing out which will most-likely be causing your compile problems are here. These intersections will split the faces that aren't currently split in Hammer/Jack during the compile, so it's often best practice to manually split those faces with clean brushwork yourself, rather than letting the compiler do it, potentially causing the tiny cracks between brushes Captain P mentioned. It might look fine in the editor, but the compiler could have different ideas.

I always tended to visualise what the compiler does with face splitting with this tutorial. This might be years out of date, but I've used it as gospel for about 15 years. As I understand it, the compiler will essentially perform the carve operation, whereas doing it by hand allows you to create clean, legal brushwork as in the vertex manipulation example.