Techniques for working on a 3D skybox

One of the issues I've had with map making (and the large open world maps I tend to do) is creating a skybox as I go, or with making changes to geometry, and then having to redo my skybox. Normally I have lower quality func_detail versions of my buildings in the skybox so I can clip out to the skycam and not have buildings just pop in out of nowhere.

So here's a nice technique that let's you easily make changes to your map and reflect them in the skybox as well without all the hassle of trying to figure out the appropriate position the brushwork (or point entities) should be after translation.

The first thing is to set your grid limit to the maximum in Hammer (512)

Then place an env_cubemap at the top NE side of the map (16384,16384,16384)

Then place another env_cubmap at the bottom SW side of the map (-16384,-16384,-16384)

Place your sky_camera at EXACTLY (0,0,0), set the properties as desired.

Decide on some multiple of 512 to have your skybox, we will call this NUM, I pick ten, (though your skybox will end up below this after scaling)

So select your two env_cubemaps, sky_camera, and whatever reference geometry you want in your skybox.

Press SHIFT-UP once (with grid at 512), so you copy the selection.

Then press UP NUM-1 more times (so if you use ten, like I did, press 9 more times)

Transform the selection by 1/32 (0.03125 in x,y,z)

Ok, nothing special so far, but here's the trick. Let's say later you add a large building that you want to place in your skybox (so you can see it in the distance).

Select that brushwork, etc.

Select the two env_cubemaps as well.

Press SHIFT-UP once (with grid at 512) to copy the selection.

Then press UP NUM-1 more times

Transform the selection by 1/32 (0.03125 in x,y,z)

It's in the perfect spot. func_detail, etc as appropriate

The env_cubemaps make sure when you scale the selection, that it's scaled relative to the origin (as they make the selections always the same size as the world). I use env_cubemaps as they don't leak so it's no hassle if they are outside the map.

Something like this would actually be a nice option for hammer, scaling your selection relative to the origin and translating it to the sky_camera, but this does the trick as well.

NOTE!!!! One thing I ran into and you should be aware of it. If you forgot to delete the original sky_camera (ie have more than one in map), all your nav will be blocked

Scroll to top