Introduction

You may be new to mapping. You created a brush in the dimensions you wanted with the texture you wanted, but it's doesn't look quite right. So you select your brush and toggle Texture Application Mode. You try center justify, but the texture still doesn't fit.
Aah, fit! There is a button next to the other justification buttons called just that, Fit! You press it and voilà! A perfect fit!
Everything's fine, right? ...right?

You might not be aware of it, but you just made a mistake that might lead to the map not being able to compile or to be run by the game.
When you selected the entire brush and press Fit, the editor performed this fit on all faces of the brush. Even the sides of the brush, which in our case are very thin and small, which resulted in this face having a very small and stretched texture.

How to fix

Before we do anything else we need to fix our mess. Select all brushes you've used Fit on, toggle Texture Application Mode and if you're using Hammer you will need to reset the scales manually by setting both X and Y to 1. If you're using J.A.C.K, you can hit the Reset Button.

Using Fit correctly

Does this mean you cannot ever use Fit? No, of course not. It's there for a reason.

The key to using Fit correctly is to use it sparingly and deliberate.

• Don't use it on an entire brush at once but instead select the specific face(s) only.
• Make sure the faces are similar in size and aspect ratio (i.e. match up tall textures with tall faces, wide textures with wide faces, square with square, etc).
• Avoid using fit that will cause the scales to go below 0.1. If the X and Y scales differs a lot, then you didn't follow the previous point.

That's it! As long as you avoid causing textures to be stretched or have very small scales it's perfectly fine to use Fit.
Of course, most of the time it's better to just use the scales manually so I suggest you practice doing that instead of using Fit. 😄