Window design is a very important thing in your Doom-engine maps because you always encounter a place, where you want to put a small opening into a wall, but what to do if you don't have anye idea to spice it up? Well, this is the way I do it!
In screenshot number one you see just a simple window of BROWN1 with a metallic/spacey border around it (SHAWN). It's a simple addition but it makes your window look damn beautiful and very real! (buildtime 5-10 minutes, mostly because of aligning textures)
The second shot just shows another window of the same style, but this time, I put another texture (SHAWN1) into the middle of this metallic thing, made it translucent (120) and then added the BLOCKEVERYTHING flag to this line. The result is a very solid and beautiful window in your very own UAC base ;) (buildtime 8-12 minutes)
And the third shot shows the last alternative for Tormentor667-styled windows. This time, I also put another line into the center of our metallic border, but this time it's a transparent texture (MIDSPACE) on which we just put the IMPASSABLE flag, so the player and monsters still can shoot through this. (buildtime 8 - 12 minutes)
Summary: These 3 examples are - as the name implies - just examples of base structures for your windows. Without any problems you can change textures, size, style and overall-look of your window to make it fit in other styles of maps (for example a combination of a METAL border and a MIDGATE center-texture). Play around with this and develope your very own style of windows :)
Extra-Buildtime: "5-12 minutes" (can be copy&pasted easily)
Build-Difficulty: "Low - Medium"