LEAKS EXPLAINED

 

WHAT ARE THEY?

Leaks are possibly the MOST annoying aspect of level design. At any point in your level you leave even a one unit gap it will be a leak and disaster will strike.

 

WHAT DO THEY DO?

If you have one, no lighting will be performed and it will look awful, also no VISing will be performed either.

VIS is basically the tool that works out at any point of your level what the player should see, meaning not all of your level is drawn by the engine a one time, this is why designers use S-shaped corridors to stop the engine drawing large areas. If there is no VIS you can imagine the slow-down if the whole level is drawn.

Let's look at some examples below:

Here is a corridor that I made, as you can see it looks quite nice with the dim lights and lots of shadow.

Let's have a look at the same corridor with a leak in it.

Dear me that looks crap! Have a long look at that screenshot and see if you can see the leak

Found it? Well it is a tiny one in the wall, just right of the pillar before the stairs

There it is, hard to spot aren't they?

Right let's look at some ways to track them down.

Firstly build really neatly, meaning zoom in to check all the gaps are sealed and take your time. If you do this it is possible to make levels without even having leaks. But they do attack eventually so lets look at the first way of finding them:

Now that shows up really well doesn't it? What I did was make the outside 'void' a red colour. To do this I used the console command GL_CLEAR 1 and it makes the leaks very obvious.

The only real problem with this is that Counterstrike sees this as a cheat meaning it is has been taken out. This really only works on HL maps and the like.

The best method then, and it works on CS is to use something called POINTFILE. This basically draws a dotted line that bends mentally through the level and then passes through the leak. All you have to do is follow the line to your leak.

See the line in the picture? It goes right through the gap. This is a sure method to find leaks. To activate it bring down the console and typr POINTFILE and then the line will be displayed.

VHE can load the pointfile but makes it pointless because you can't see it in the 3D view. Much easier to use this method.

SO LEAKS ARE JUST CRACKS IN THE WALLS THEN?

Erm..Afraid not. There are other ways to cause leaks would you believe it. The hardest one to spot is if you try to seal the level with an entity, say a func_door or a func_wall. Have a look below:

There is my level and I have blocked off the void with an entity (the purple part) according to the BSP program (the bit that checks for leaks basically) this may as well be a gaping hole. My only advice is to be careful with what you do and if you do need a door there then put a solid block behind it and under it to seal it in.

Lastly the other kind of leak is if you leave an entity in the void say for example a light. This is fortunately very rare but if you having a hard time finding a gap then quickly zoom out and check there is nothing in the void of VHE.

Well I think that is all to do with leaks, Finally I can't stress enough how much careful design will benefit you.

Good Luck

By Blink