Quote Originally Posted by kacey View Post
I have a few ideas in mind and have done a couple of small tests using Wilbur with good results, but my surface doesn't like doing the rivers for some reason, I keep getting a little window saying Wilbur is not responding. When I do a smaller size image it does work though so I'm chalking that up to a lack of computing power so I'm not too worried since I just got my new desktop put together this weekend and it's running really well.
Wilbur doesn't update the UI like it should while it's doing the initial flow computations. Those computations are a bit more than O(n*n*n) (the time taken is on the order of the square of the number of pixels), so larger surfaces take much longer than you would expect. As an example, if we define a 1000x1000 pixel surface (1M pixels) to take 1 time unit, then a 2000x2000 pixel surface (4M pixels) would take more than 16 times as long. There are also effects relating to the total length and complexity of river channels. The short answer is to wait. Sometimes you'll need to wait 10 minutes or more, during which the OS will whine about the program not responding. If the Wilbur CPU usage is remaining consistent (Ctrl+Shift+Esc to bring up task manager) during the find rivers operation, then it's probably still doing useful work. There are also a couple of size breakpoints where the speed will dramatically slow: surfaces larger than the CPU cache that require fetching from main memory and surfaces larger than main memory that require fetching from disk. Wilbur isn't very smart about how it manages memory, so it tends to be pretty sensitive to switching to slower storage.

I will admit to having very little patience at the best of times, so I don't do well waiting for the program to finish its work on large surfaces. I developed the multi-resolution techniques described at https://www.cartographersguild.com/a...chmentid=80066 to try to reduce my total waiting time. The main elements get roughed in at the lower resolutions to where you're happy with them and then the details can be etched on top of that. How small you want to start with depends entirely on your level of patience. I tend to start out small and chop in things where it's only taking a few seconds to process on my elderly i7-3770. The surface has a somewhat different appearance than one eroded fully at the higher resolution, but I'm willing to live with spending a total of 15 minutes or so rather than 15 minutes or so per iteration. Then again, I usually don't care too much about smaller details, either...