I thought this might be useful to someone. While working on my mine carts, I was trying to figure out how to bend my straight tracks. Now, I haven't quite mastered this, but I can at least make 90 degree bends that don't necessarily (as we like to say around the office) suck out loud.
Let's say I'd like to make my tracks take a 90 degree turn over a 600px area. I've got a straight track that is 30px wide. I'm going to start by making a new image that is 1200px by 1200px, and I'm going to make a length of straight track run along the very top of that image. Then, stretch the track so it's twice as thick. Now, I've got a 1200x60 px track along the top of the image.
bend_pipe_1.jpg [ 105.32 KiB | Viewed 8863 times ]
From the Filters menu, select Distorts > Polar Coordinates...
My settings are:
Circle depth in percent: 100.00
Offset angle: 0.00
Map backwards (unchecked)
Map from top (unchecked!)
To polar (checked)
bend_pipe_2.jpg [ 34.25 KiB | Viewed 8863 times ]
Click OK. This should turn your straight track into a circular track.
bend_pipe_3.jpg [ 106.78 KiB | Viewed 8863 times ]
Now, grab a 600x600 corner of the track, copy it, and paste it into a layer in your destination image.
It will blur the texture on the bend, so your mileage may vary as to how good this will come out. You might improve the results by creating a texture layer or applying a bump map after bending things like this.
When I connect my straight track to the bent track, I try to blend the collection together by cloning some un-blurry texture at least onto the ends of the bent piece, so the transition isn't stark.
At least now, I've written down the process, so if I go another couple weeks without doing it, I won't have to completely retrace my steps! Happy kitbashing!