Introduction
With ships, it's sometimes very important to add decals. The way most modelers add them is ether through mesh modeling, which is very tedious, or textures which can be very hard to align when you have a really complex mesh. This tutorial hopes to tackle that problem and make it very simple to align your decal.
*This tutorial is based entirely on the Theeth CJ Decal tutorial.
Steps
For this tutorial you'll need an object, I suggest you use a ship of some sort, but if you can really use any object. Add a new material to the ship, then a new texture, choose image and the select any picture you want, then select 'Clip'.
Now add an Empty, place it where you want the decal to appear on the ship, the Z axis should be perpendicular to the surface, if you rotate or resize the empty, it's going to effect the decal.
With the ship selected, go to the materials window, you should see a tab to the right called 'Map Input', under that you'll find a button called 'Object', select it and then in the space type the name of the empty (which should be 'Empty').
Well, that's it. It's very simple, but very effective, if you resize, move or rotate the empty, the decal should do the same.