This is a very important aspect of map making but also very easy to explain and understand.
Imagine you are standing in the middle of ctf_orange. Now think about which path do you want to choose. Do you climb the tower and try to surprise the enemy from above. Or do you take the short direct path, but with the danger of running into more enemies than you can handle.
That's what I call good path balancing, each path to the objective (in this case the intel) has its own advantages and disadvantages. Every time you get to the middle you have to think about which direction to choose and it's not an easy decision.
Bad path balancing is when there's no real decision or the decision doesn't matter. Think about the top route to the intel in classicwell, it gets used almost never because it's too long and you have to go past the main spawn exit. And that's why it's almost never worth it. You might as well cut this part out of the map and nobody would notice.
On the opposite side of the spectrum is when a path is just too good to not use. In heenok2 the scout path is so extremely OP because you can avoid almost all enemies. The only thing you have to worry about is other runners and the people camping the intel room (read: one lonely engie).
What you want to avoid too is having all the paths be too samey. If all the options the player has to make are essentially the same, then the decision which route to take is not interesting. One map that is partially guilty of this is waterway. ...Actually on second thought, this is a good technique to scatter the players as most people will choose one path randomly. So it's more of a style thing rather than good or bad.
So let's talk about what makes a particular path attractive or unattractive. The two most important aspects are length and congestion.
- With length
I mean how long it takes you to traverse said path and NOT the distance in pixels. This is an important distinction, because a short looking path can take relatively long to travel through, think of those boxes in the conflict sewers.
- With congestion
I mean how busy that path is, how likely you are to encounter an enemy. The shortest path is usually where the most players are.
Now the next few factors are more minor and the majority of the players won't consider them when playing.
- Number of Options
, by which I mean how easily can the player switch to another path. Example: In ctf_dirtbowl
taking the normal path has the advantage that you can quickly drop down to the sewers, but in the sewers you can't easily go back to the upper path.
: How likely it is to get spotted by the enemies/to see the enemy in advance. A flank is a lot more effective if the enemy doesn't see you coming.
- Class specific advantages
: Say a long spammy hallway attracts soldiers, a twisted path with lots of boxes and cover makes pyros happy. Be careful that you don't cater a path too much to a certain class or you'll create boring one-sided gameplay.
- If you want to overanalyze it, then you can look at all kinds of tactical advantages
like cover, height advantage, feasibility to retreat, etc.
To summarize: Path balancing is about giving each path up- and downsides. It makes your map deeper and more interesting to play. This knowledge also helps you (to some extent) to predict how the map will be played.