Ran into a little problem, my knowledge of texturing is very limited:

Well I've made the main part of my map (corridors, rooms, balconies) with SketchUp, got it into XSI fine (obj. export rather than KMZ, stops all the rotate and component problems), and made some props in XSI. I'm just having this one problem with texturing stuff:

Some of the corridors (identical to other corridors otherwise) bend round a corner in a 90 degree arc. Some of the pipes for props also have such bends (90 degrees in a circular arc). Texturing them is a nuisance...there are lots of inconsistencies even with painstakingly editing one poly at a time. So my question is: Is there a simple(ish) way to get textures to follow a model around a curve/arc, or do you have to manually do it polygon by polygon?

if you didnt create the pipes via extrudiang along curve in XSI you have to do it poly by poly as afar as i know
if you use the extruding along curve function in XSI you can XSI create correct UVs automatically

How? Because when I extrude polies (curve or axis) I just get super stretched textures.

first you create a curve that is shaped like your pipe (or you could just use the circle curve)

then you create another curve which defines the lenght of the pipe, you can twist bend and do whatever with it

next you select the shapecurve and click under create on polymesh>extrusion along curve and select the lenght/second curve then you mess with the settings and click on the "generate" button below automatic UVs in the right upper corner

now you have a clean UV for your pipe and you can even edit both curves and the mesh yu created will be edited this way too

when you are ready to export and satisficed with your pipe, freeze its modeling (the "freeze M" button)
if you dont do this the curve will become messed up while being exported and sometimes you cant undo it anymore

What I do (because I don't use extrude along curve to create curved tunnels etc.) is take segments of the tunnel and give them cylindrical subprojections. I don't know how that compares with what DarthD.U.C.K. refers to, but it seems to work fairly well.

well yes, if they bend really only in 90 degree arc then using cylindrical subprojection is easyer