How to taper edges of an arch?

First of all, i am sorry if this has been in another thread. I’ve been searching around and can’t find anything about this subject. I can’t figure out a good way to “taper” or cut the edge of this arch all the way around evenly. As you can see the ledge it is connected too is cut. I would like it to do this all the way around, can anyone tell me how?
Here is the picture:

I also have another question i might as well ask on this post. I am making a sliding door for a jail cell. I made the door part a function_door or what ever the entity is called. It works fine except when i load the map, the door is rotated instead of being upright like a normal door should be.

Try making the arch brushes triangles with the vertex tool.

That doesnt work because the vertex of every brush wont be on a grid point, so you wont be able to use it.

They will if you use the arch tool properly

I’ve tried using the vertex tool, I highlight the two edges of each object in the arch and match it with the ledge but it just doesn’t come out right after i do it all the way around. It makes the objects in the arch become crooked.

Slice the curved piece in half (in line with the top corner of the chamfer) and then just vertex manipulate the bottom edges of lower arch inwards.

You could make a 360 arch with the same thickness, cut it in half horizontally from the side. Select the bottom half then using the vertex tool select the outer-bottom vertices and hold and press ALT-E (I think?), which then a small window should pop up allowing you to type in some numbers in the appropriate place that should allow you to make the circle smaller from above. Find the right number you want then press enter. You can then just cut a quarter out of the arch and put it in place, should fit perfectly if the side number of the arch is not odd. Oh and you might have to adjust the vertices at the edges to match up.

I wouldn’t suggest making it out of triangles. This is the most brush consuming way to make things and to be honest it does work, very well but is rubbish for texture aligning and isn’t the most optimised way.

I would also like to mention that even though the points will be off-grid it will not be an invalid brush. Blame Valve. It’s to do with the way the polygons in the brushes are facing, they have to be natural to the brushes intended shape or it fucks up, hard to explain.

Anyway, there’s a pattern to selecting vertices in a cylinder. It’s usually something like this, it really depends on the amount of sides it has.

http://img17.imageshack.us/img17/5697/taperw.jpg

About your rotating door issue by the way take off both X and Y in the Properties > Flags.

I wouldn’t bother using alt+e unless you want off grid verts, even though vbsp fixes them, it’s still messy.

[editline]8th January 2011[/editline]

Oh and about the invalid brush thing, it’s because it has to be planar, otherwise vbsp cannot handle it (concave is possible so whether it is or not, it spits out an error.)

You can adjust them without causing invalid brushes. It is certainly not messy, it’s the most efficient, optimized way. It’s perfect for this kind of thing.

http://img600.imageshack.us/img600/4148/taper2.jpg

I was obsessed with the vertex tool for 6 months, I still am. It’s quite a great tool.

Meh, I can do that manually and it’ll all be on grid.

You can’t do that. Faces have to be co-planer or it will end up in a error or the face being removed. Besides, the arch tool does not create mathematically perfect arches. They are approximated because vertexes are assigned to a point. Props to Death doing it, not sure how. I think displacements are your best way, it just takes some time.

may be a long shot, but could always try with displacements. But you would have to be prepared to use them.

Funny, because it generally works ok for me when I manually vertex manipulate it.