Texture alignment woes

Could somebody help me out with texture alignment? I know how to do it but is there any way to know exactly how much to set the offsets to make the texture perfectly aligned? I've just basically been guessing, and that takes forever to get the right alignment, and is really slowing down my level editing.

You can simply calculate it. If you've got a wall that is 64 long and split it in the middle, the right line needs a x-alignment value of 32 to look good.

At least one editor allows sort-of automatic texture alignment. In WadAuthor, simply select the lines you want aligned (they have to be contiguous), right-click your mouse, and select Align Linedef Textures. Voila! Otherwise, do as Tarin suggests, and calculate the offset value. A simple rule of thumb is to offset the texture by the sum of the lengths of the linedefs that are to the left of the linedef you want aligned. Say you have a wall that is 128 wide, that is split into 4 equal segments. The texture you wish to use is 128 wide. The first line segment (L1) will have no x-offset (i.e., = 0), the second (L2) will have an x-offset value of 32, the third (L3) will have a value of 64, and the fourth (L4) will have a value of 96. If the line segments are not equal, then do the following: first segment x = 0, second segment x = length of L1, third segment x = L1+L2, fourth segment x = L1+L2+L3.

It gets a little more complicated if for some reason you want the first line segment (L1) to have a x-offset. In that case, figure out what your x-offset for L1 is. For L2, add the length of L1 to the offset for L1. This is the x-offset for L2. For L3, add the length of L1 and L2, and then add the x-offset for L2. This is the x-offset for L3. Etc., etc., ad nauseum. Hope this helps.