put a minus sign "-" in the properites in either the "X" or "Y" it will turn around.

uhh, so? how can it be a correct answer?

lemme look inside my VHE and get you some precise instructions

Decals are like bullet holes. Ever played the game in software mode and shot a large scaled wall texture? Massive bullet holes everywhere. That's pretty much fixed in OpenGL or DirectX but you can still mess up the decals by having your texture not scaled squarely (i.e. 1x 4y) Bullet holes (like sprays and explosion scorches and such) are all just decals applied in game.

So: Decals are applied on top of the texture. If your texture is rotated, your decal will be too. You can't rotate just the decal. You also can't scale the decal unless 1) you made your own custom one, or 2) you didn't scale the underlying texture squarely, which would cause it to stretch funny on one side, or 3) everyone who will play the map is in Software mode, and you've applied the decal to a scaled underlying texture.

It's not a problem with Hammer or Worldcraft or whatever, it's a quirk of the game engine. Recommend that you create your own custom "damaged" textures anyway, since they can get a lot more detailed than the monochrome decals available in HL.

I think. Maybe.

its good to know advice, i guess i was really lucky and always had my textures aligned properly, cause my decals have allways applied correctly, at least in relation to how squared they were, sometimes i did lose them inside a wall and that was annoying as hell

good question/answers