Making Simple Arches ("Bevel Method")
Intro
This method of making arches is considered by many to be the most efficient way because it creates less sparklies as opposed to the end-cap method. Its up to you which method you want to use, though this method is considered the best.
Map Prep
First up lets sort out where the arch needs to be placed. Ive made a simple tunnel, Fig. 1
Creating the Arch
Now we need to create a brush for the first bevel, this is going to be half of the arch. So create it half way across the width of the tunnel, as shown in fig 1.2 and fig 1.3
If you look at the brush we created (in red) if I was to make it longer, by that I mean if I moved it up in fig 1.2 then when I made my bevel it would end up being a more tight curve.
Now with your brush selected go to "curve" and then chose "bevel" from the toolbar. It will now create a bevel out of the brush, fig 1.4 As you can see its not facing the correct way or at the right angle, what we need to do is rotate it using the rotate buttons, fig 1.5
Ive had to press the X>x button, its then facing the right way, so I have then moved it into position on the right side of the tunnel, fig 1.6, 1.7 and 1.8
(Fig 1.6)(Fig 1.7)
(Fig 1.8)
You can see that the face or texture is facing the wrong way (see fig 1.6).
What we need to do here is go to "curve" then "matrix" then chose "invert" it will
then move the face to where we need it, fig 1.7
(Fig 1.7)
What we now need to do is stretch out the piece so its the length of the tunnel, the texture will stretch as well though, so what we need to do now is make the texture go natural. To do this select the piece of arch and then press "s" to bring up the texture applicator, and then press the "natural" button and then "done" (you can also use the curve texture applicator for some texture movement, to use that press shift and s)
Go to "curve" and then "cap selection" and a window will pop up, fig 1.8
The parts in blue are the parts that will be the new brushes/patches, although our arch is facing the other way to that of the picture, we need an inverted bevel, you can see it is the same shape as our half arch only facing the other way, it doesnt matter that its facing the other way in the picture, it will make it properly, so choose "inverted bevel" and then press "ok", fig 1.9, fig 1.10
You can see that the texture on the front has actually aligned up, so theres no need to align it, if it doesnt align up for you, try using the curve surface inspector (hold shift and press s)5. Now we have half an arch. Before we copy it, ive stretched mine out to the length of the tunnel. All you then need to do is select the arch piece and press "space" to copy and paste it and then you need to press "x|x" on the toolbar for it to rotate to face the correct way. Then you need to move it into place, or move it into place and then press the "x\x" on the toolbar, its up to you, as long as you now have a full arch, fig 2.1:
You will notice the brick texture on this arch on the inside are going length ways, you can rotate them if you wish so there like real bricks (horizontal) you can hold shift and press s, to bring up the curve texture window.
Its difficult to align brick textures with the brush walls on arches, often you will see people use plain textures or leave them as they are in fig 2.1, or you might have an arch texture if you are making a smaller arch.
Now we need to caulk behind the arch where you cant see, as we can see our arch doesnt go all the way to the floor so we need to make some more brushes. See fig 2.2 and 2.3 First lift up the 2 walls and then add some new walls below them, fig 2.3
Now the top wall brushes can have the caulk texture applied to the faces facing the arch, you need to also apply it to the ceiling face that faces the arch, first hide your arch, press "h" and then apply the caulk texture, fig 2.4
For even further optimisation we should move some vertices, by this I mean move the walls into a triangle shape at the top and the top ceiling brush needs some vertices to move, then you need to caulk the faces that wont be seen. See fig 2.5, fig 2.6, fig 2.8
Unhide the arch by pressing "shift" and "h", your arch is now done. Go test it out.
Usually with this method no sparklies will appear and its easy to align the textures where are in the end cap method of making arches you might get some sparklies. Ill leave it up to you which to use, there are tutorials on both, its most peoples view that this bevel method is best.
(Note you dont see the white caulk texture coming through in game obviously as thats invisible)