About carving

A Tutorial for Goldsource Engine


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Become a lean, mean, carving machine

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As a beginner mapper, you've probably heard of and used the Carve tool. Some swore by it, some avoided it. I know I used it for sure.

Let's imagine a really extreme case where our imaginary mapper decides to write a carving tutorial. And of course, he's the part of "some swore by it" category.

Hello m8s today i will show u how 2 carve
Lets see how to make a good VERY GOOD realistic hole in teh ground

i just don understand y ppl waste so much time on hard and complex procedures when you can just use da carve tool!
carve tool was always my best friend and it made my life EZ af

step 1

make a ball with at least 20 sides
the more sides, the more realistic your hole will get :D

step 2

place the big bol into the ground by 16 units or so
and then select the big bol

step 3

go to the tools tab and press carve (or ctrl shift c if your a pro)

stpe 4


clap... clap... clap...

Congratulations Mr. Carver, now your map has 84 additional brushes and 3 of them won't compile into the final map because they have geometry issues.

Just don't. There's a better way.

Carving is one of those taboo topics in GoldSrc mapping. Not just GoldSrc. It's anything whose mapping is based on additive geometry. In Unreal Engine 1 though, mapping is solely based on carving rooms and adding brushes inside.
99.75% of mapping experts are going to tell you to never ever use the Carve Tool.

However, only 0.25% will tell you how to use it correctly.

In this tutorial I'll show you how to hand-carve, as well as perhaps the only couple of cases when you can use the Carve tool with 0 errors.
The hand-carving will cover simple '2D carving' (hand-carving done in 2D views) and full 3D carving (e.g. carving a part of a sphere into a block).

Some people say it's okay to carve blocks into blocks. While this indeed is a non-lethal way to use the Carve tool, I'd recommend you to do it manually.
If you've been carving blocks into blocks with the Carve tool, just stop and start using the Clipping tool.
Carving these two is perfectly easy:

There are a few simple rules:

- select the brush that will be carved into (not the one that will carve)
- switch to the Cutting tool and cut it along parallel lines of the carving object, or the carved object, depending on the situation (not applicable with spheres, cylinders and spikes, and in half of the cases with arches)
- if necessary, remove the excess brushes
- if necessary, merge some brushes

Let's see how this applies to our scenario of two simple blocks.

We'll be cutting it vertically, parallel with these two sides.

Now we'll cut once, either from the bottom side of the carving brush, or the top side. After that, we'll just scale the other part accordingly.

This is a very simple example of it.
Let's see a way to hand-carve windows.

In this case, we'll cut the carved brush horizontally, to save up on brush count.

Then we cut the middle brush vertically, according to our window brushes.

Let's see how the 2 ways compare:
Horizontal first - 13 brushes made out of 1 brush

Vertical first - 31 brushes made out of 1

Cutting vertically first is more ideal for texturing if you want to have more control over individual faces, while cutting horizontally first is good for reducing the brush count.
Alternatively, you could cut them like this:

This one counts 25 brushes and is ideal for deforming the windows like this:

Those were simple blocks.
Let's see how to hand-carve a skewed brush.

There are multiple approaches to this. We can cut the carved brush like this:

There will be an extra brush in the middle, so remove it.
However, if you were making this as a room, make sure to trim the unnecessary parts of the floor and ceiling brushes:

Skewed brushes are as easy as normal blocks. But what about a hexagonal prism? (6-sided cylinder in J.A.C.K.)

We could cut it the same way we did skewed brushes.

And once again, if it's a hallway or anything indoors, make sure to remove the unnecessary brushes and make changes to the floor and ceiling:

Alternatively, you could keep the walls and turn the ramps into func_detail.

A similar principle applies to carving 8-sided prisms.

This is where it gets a bit different. Now you'll cut the middle square diagonally, vertically and horizontally:

And then we'll cut each newly formed triangle like this:

Actually, better delete the other 3 quarters, and just clone this corner to save some time.

The Carve tool would produce something like this instead:

The problem with the Carve tool is that it produces off-grid vertices in this case, and not just that, but once you try doing anything with the Vertex Manipulation tool on it, you'll make it worse.

With the hand-carved brushes, you have more control over the shape, whereas brushes produced by the Carve tool end up being irreversible and shouldn't be tampered with.

Judging by the screenshot, one would argue that the Carve tool produced less brushes. Well, I could've just cut the block immediately like this:

That way the brush count is the same on both sides.
In fact, this is an even better way. This is also exactly how you can carve a cylinder into a cylinder.

Then cut it along the carving brush's contours:

It looks like a pizza. Let's call it the Pizza technique!

This will work with any-sided cylinder. This technique will also be used with carving a sphere into the floor, albeit with a few extras.

Lastly, for '2D carving', we'll carve an arch and a triangular prism.
First, a triangular prism.

This one is pretty special. Cut it like this:

Then remove 5 brushes: the middle square and the corner squares.

Then select the remaining carved brushes, and enter the Vertex Manipulation tool.
The order isn't really important, but I prefer to do it from top to bottom.

As you can see, the top square will become a triangle.

And now the bottom:

This is the finished result:

If you want, you can connect the top 2 edges and it will basically look like a triangle carved into another triangle.

I actually picked this way on purpose, since there are more ways but they would require merging some brushes, and Hammer 3.4 simply doesn't have that function (as far as I'm aware).

Lastly, time to carve an arch into a block.

This will be a combination of the Pizza technique.

Firstly, cut it horizontally:

And then:

Now, the hardest part (which isn't actually hard). We're going to cut the upper part this way:

Then we'll cut the triangles like this:

Repeat for all triangles. However, we're not done yet. We have off-grid vertices.

This will take a little bit of time, but lower Snap On Grid to 1, enter the Vertex Manipulation tool and just snap them back onto the grid:

Now you can remove the additional brushes, and merge the half-circle:

That's pretty much all of it for 2D carving. Let's get into full, 3D hand-carving.
We'll start off by carving a block into a block, again.

Since the brush is rotated this way, let's start in the top view.
Cut it exactly like you did in 2D carving:

And then select the middle carved brush:

And trim the excess part:

Alternatively, you could've cut it initially like this:

The process of carving n-angular prisms into a block is based on this technique and it's pretty much the same as 2D carving.
The difference is that, instead of deleting the middle brush, you just scale it down in one of the 2D views.

However, let's see how to carve an inverted spike.

Firstly, you choose whether to 'box' it, or not:

In this case, I won't. But, there may be situations when you'll need to box your hand-carved figure. It can be because of texturing, or maybe brushwork reasons.

Then cut it in X-shapes:

Now, we'll do the Pizza technique, without removing the inner brushes.

Then we'll select the middle vertex:

And pull it down according to the carving brush.

Now you can remove the spike itself and merge some brushes.

This is essentially a simple crater.
Let's carve an 8-sided pipe we made earlier, into a block.

Start off by cutting the carved brush like this:

Then repeat the Pizza Method, i.e. cut the first quarter of triangles along the carving brush's contours:

Delete the other quarters, and clone the quarter that you've cut.

Also, don't forget to merge the middle circle.

Lastly, we'll see how to carve a sphere, and then how to use the Carve tool itself properly.
Before proceeding to carve a sphere, let's do it on a simpler example:

First we'll cut the cube into 4 parts:

And then we'll cut each triangle along the carving brush's contours:

Now, this part is going to be messy.

It's actually not a big deal. Just select the vertices you have to select:

And then, either in one of the 2D views, or in the 3D view via PageUp and PageDown, move the vertices vertically:

And you're done.

The same principle will be used in regards to carving spheres. The difference is that it takes more time.

Start by cutting the brush into triangles.

Then cut each triangle along the lines of the sphere:

However, there are quite a few off-grid vertices. We'll have to snap them back onto the grid.

You'll have to do this for every off-grid vertice you encounter. Next, move vertices according to the sphere:

If you get errors like "Point off face plane", "Brush is not convex", "Face not planar", then you should go to that brush, 'flatten' it and cut it diagonally:

If you want to be 100% secure, cut each part diagonally and then move their vertices. However, that will raise the brush count by a factor of 2.
In the end, clone the quarter you've done and congratulations, you will have successfully carved a sphere.


The Carve tool is really hated by a lot of expert mappers. They think of it as a joke. That's true, but there can still be situations when you could use it without errors afterwards.
Most notably carving a tetrahedron.

If you just want a simple, little piece clipped off a cube, you are free to use the Carve tool to subtract a tetrahedron from a cube.
Click on the tetrahedron and press Carve.

As you can see, this is error-free and produces no off-grid vertices.

We could've also just rotated the brush in the Select tool and cut it... oh. That would produce off-grid vertices and we'd have to align them with the Vertex Manipulation tool. I guess the Carve tool wins this one.

So that's one little trick with the Carve tool. Most people just avoid it completely, while others depend on the Carve tool. Avoiding it completely is perfectly fine, but depending on it isn't.

Remember that arch we hand-carved earlier?
It's not a problem to do something with the Carve tool either, albeit take it with a spoonful of salt.

But then, making that brush with the Vertex Manipulation tool is faster than making that entire arch.

The point is: the Carve tool can be used in the way it was not really intended, and it's the only way it can produce error-free results.
Of course, I'm talking about carving something into a brush but the brush still remains convex.

When you carve a sphere into a block, it becomes concave so it has to be cut up into multiple, convex brushes.
And that is where the errors occur. You can get micro brushes, off-grid vertices, and 'infinite' brushes. Don't use the Carve tool to carve into something that would make it concave in a way.

If you still have to carve with the Carve tool, then at least do some damage control.
Don't just carve a cylinder straight ahead into a block. Instead, cut the block according to the cylinder's bounding box.

Without damage control.

With damage control.

Also, you don't need to carve in some situations. You can just leave a brush inside another brush, because in the end, HLBSP will carve them by itself, producing some more world polygons.

Lastly, we'll carve a map into a map.

Step 1. Open your first map, select all world brushes and copy it
Step 2. Open another map in a new window
Step 3. Press Carve.

Happy April Fool's Day, and happy mapping. :)

(If you still don't understand, the first one, and this last one are jokes)
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  • Barnaby avatar
    Barnaby username pic Joined 2y ago
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    I like the objectivity.

    Almost all mappers really do tell you to never use the carve tool. I had a talk about this on the source mappers discord community, noone really was objective about it. Blind hate, really.
    It does have its uses.
    I dont know about this. avatar
    I dont know about this.
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  • X RaY avatar
    X RaY username pic Joined 4y ago
    Black Mesa Inc. Flag Affiliation: Black Mesa Inc.
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    X RaY avatar
    X RaY
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    Can u give rmf? I would like to investigate it
    Another Black Mesa Fan <3
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  • ficool2 avatar
    ficool2 username pic Joined 4y ago
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    Just so you know, you can use Ctrl + B while all vertices are selected to snap them onto the grid, very handy to save a lot of time (though it requires a little bit of tweaking)
    Source Engine Addict
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  • gladeare avatar
    gladeare Joined 4y ago
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    "If you want to be 100% secure, cut each part diagonally and then move their vertices. However, that will raise the brush count by a factor of 2."

    Please note that source does not support quads and will make these cuts on its own. Do not be afraid to cut every suspicious quad you see into tris, since if you have any invalid quads, there will be unforeseen consequences

    The only way it can have any negative influence on your project is if your editor is not capable of displaying this many lines, in which case you should question if mapping is really something you should be doing on your computer.
    -dono avatar
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    Ghost1397314 Joined 4y ago
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    Really useful, I've always used the Arch tool to make holes, now i can learn about Carve tool with this tutorial.

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Admer456 avatar
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Writer, screenshots
Borrowed from
TheGrimReafer on TWHL
2 screenshots (replaced now)


Admer456 avatar
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Gone. :3
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