Skybox across building tops

Open Blade

Open Blade

L420: High Member
Nov 30, 2007
439
34
I've seen this before in other maps where the skybox covers the tops of angled roofs and what not but yet in the game you can see the building just fine. I tried that and some of the walls of my building appear as if they have a no draw on them, which they don't. The skybox has the correct texture on all sides so I'm baffled as to why one of the walls was see through. Since the skybox brush is still a world brush, I wanted it to be even with the wall to keep a nice clean face so I didn't break up the vis plane, or whatever you call that.

what's the normal rule on using skybox across building tops to seal an area? I func_detailed the angled roof but the 4 walls (one big square brush) is not func_detail so it can seal to the skybox brush.

Thanks.
 
TracerDX

TracerDX

L3: Member
Jun 9, 2009
127
26
Remember that Skybox, 3D or not ALWAYS draws first. This implies that your skybox hull must never be concave. Else, you'll have world geometry drawing on top of the 3D skybox geometry in ugly ways.

Ie. You should never be able to draw a straight line from inside your hull, through the skybox and back into your hull. Though, you can use clipping to mitigate this issue by making sure players cannot get into such positions.

From there, you can do whatever you want.
 
zornor

zornor

L4: Comfortable Member
Jan 14, 2009
195
23
Also when you're doing angled roofs, do them with a set gradient in mind, like 1/2. This will make your life infinitely easier when dealing with this stuff.
 
S

Sgt Frag

L14: Epic Member
May 20, 2008
1,443
710
TracerDX said:
Remember that Skybox, 3D or not ALWAYS draws first. This implies that your skybox hull must never be concave. Else, you'll have world geometry drawing on top of the 3D skybox geometry in ugly ways.

Ie. You should never be able to draw a straight line from inside your hull, through the skybox and back into your hull. Though, you can use clipping to mitigate this issue by making sure players cannot get into such positions.

From there, you can do whatever you want.
Click to expand...


That's not correct. The skybrush is not a singular brush or a collision mesh. It can be any shape you want. You can even have skybox in the middle of your map. It's just that worldspawn behind it will draw in front of it.

You just need to make sure that your skybox geometry lines up with and/or is behind your world geometry to avoid weird rendering.

You can build skybox in front of a building but you need to leave a gap. If you put it in front of angled roof and it seals to the building top (ie angle roof is behind skybox) it might not render because it is in a visleaf that is not visible form player view. It's the visleaf that controls it's visibilty, not skybox tex or shape.

The easiest thing to do is to build the skybox even withtop of angled roof and playerclip the roof. The angled roof CAN be world spawn to seal. Angles don't mean BAD. Bad use of angles means bad.

Pics would help to determine how to solve the problem you are having.
 
TracerDX

TracerDX

L3: Member
Jun 9, 2009
127
26
The way I said it was a guideline, not a technical limitation. It also doesn't apply if concave parts are not skybox. Guess I shoulda been clear about that. But if you put an inward facing corner of skybox anywhere as an outer hull, you will have rendering issues. Vis will rarely save you from this.
 
Open Blade

Open Blade

L420: High Member
Nov 30, 2007
439
34
Well I have what you call the classic displacement cliff with a tunnel through it which leads to another portion of the map. The skybox comes from the ceiling down to the nodraw walls inside the cliff, which is fine. But there is a shack on top of the cliff that is not func_detail which offers an additional route to the other side so I have to seal the skybox around this shack, which has an angled roof. The shack will be also visable from the other side of the map. I know the skybox wall at this part has to be thin but somehow seal to the top of that shackroof. Guess I can just angle the bottom of the skybox wall for the top so it connects solid to the angled top triangle portion of the roof. The actual shingled roof is func_detail so the skybox will go through that. Then on the sides of the shack, the skybox walls will touch the sides of the shack, sealing it there and then go down to the square nodraw brushes inside the tunnel, sealing it there.
 
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