UVW Unwrap is a great tool, but it does have its pro's and cons. The pro's are you get 4 different sides of a post. The cons are it literally doubles or even triples the vertice count. So use it as little as possible.

First lets start by making a 5x5x15 meter box.

Once you make your box, and convert to Editable Mesh, Click the + beside Box and choose Element. Then bring up uww mapping.

Open Material Editor, and drag/drop the material onto the box.

This is how it should look before unwrapping the texture. Right click UVW Wrapping choose Collapse ALL, choose YES.

Then you want to select each side of the polygon's 1 at a time, then select Unwrap UVW.

At This point Gmax was really acting up so switched to Max 9. Looks the same. Anyways This is the un wrap window. Top left you will see the move tool. Click and hold. Then select horizontal move. Then select the 2 right side vertices, and move just alittle inside of the first side of the texture. Otherwise you will see bleeding from the 2nd side in world.

Then select horizontal move. Then select the 2 right side vertices, and move just alittle inside of the first side of the texture. Otherwise you will see bleeding from the 2nd side in world. Do this for all sides. Sides 1 and 4 you only need to move 1 side of the verts. 2, and 3 You'll have to move both sides.

When you are done, this is how it should look. If you need a reference. Here is the example I made Examplebox.zip. Open it in gmax, and select each polygon, then choose uv unwrap to see how its done. Thats it You have now learned how to unwrap a texture. This works great for 4 wood sided textures.