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L1: Registered
Oct 16, 2018
I'm new to mapping and currently building my first map. I wanted the spawn area to take place outside but the setting isn't completely suitable to surround the area with skyscrapers like in Kong King for example. I really like the effect on Dustbowl where it looks like the map is way bigger than it actually is, and you can see all the way out to the horizon.

Reference image: https://i.imgur.com/1WEpDsW.jpg

In the image (second point, first stage, Dustbowl) the fences are the player boundry of the map, there's some more buildings and terrain behind that and then after that there's this very large plain out to the skybox only scatted with some roads and pylons. I was wondering how this was achieved?

I had a look on the decompiled Valve map but to me it just looks like the skybox is there and then nothing after. (Source: https://tf2maps.net/threads/valve-maps-decompiled.5952/)

Hammer image: https://i.imgur.com/FrH9JKk.png
(I don't know where all the props are, they don't seem to be in the map).

If anyone could shed some light that'd be great :).


Jun 17, 2010
Its called a "3Dskybox". It is projected around your map.

Basically you have a sky_camera set to 0 0 0 location of the map, copied over to elsewhere of the hammer grid, scaled down to 16th of normal size and thats how you get the effect. The camera should also exist only in the 3dskybox, and deleted from the 0 0 0 location.

If you search entity like sky_camera or look a smaller "box" in hammer grid, thats where you see whats inside of that projected area.


L1: Registered
Oct 16, 2018
Oh really that's so cool! No idea it was customisable like that. I'm guessing it's this area off to the side in dustbowl (once again the props are missing but I can't think where else the area would be) - https://i.imgur.com/rQk1USg.png.

I'll have a read of the VDC wiki on it and see if I can make it work. Thanks for the speedy reply.


I really suck!
Nov 5, 2016
Here's a quick and easy tutorial
View: https://youtu.be/hSJdlTlWOIA

It's worth noting that anything in the 3D skybox will be visible from anywhere outside. The top half of Dustbowl's rocket is in the skybox so that it can be seen from all stages.
However, because the 3D skybox always renders behind world geometry, the bottom half exists in the actual level.


Sep 23, 2011
Truth with modification. The 3d skybox is drawn only when the PVS has the skybox material visible. There is a 2dskybox material that only causes the normal skybox to be drawn if in PVS. The normal skybox material wins if both are in PVS.