There're a couple of issues associated with the rivers. The big problem is that they were generated to the earlier, lower resolution elevation grid, so they don't follow the more detailed channels well enough. The other problem is that I hadn't figured out how to set up draw priority, so if they sat on the same Base Heights as the ground, they interfered, making weird patterns. Thus I added a small,but clearly noticeable vertical offset to the river heights. I figured out how to do the prioritization, so I hope to get the second problem fixed fairly quickly.

The first bit is proving to be huge. My current iteration of the elevation grid produces a lot of straight flowlines and long parallel tribs. Hard problem to fix at high resolution. Wilbur requires a lot of noise>fill>noise>fill>... operations to make the flow more sinuous. The other erosion and surfacing app I have does better with interesting sinuosity, but it's a more physically-correct model and it takes a lot of processor chugging to get streams to converge down to reasonably narrow widths. Either way, I then have to import a river-mask image into ArcGIS, georeference it and trace it into a vector shapefile. Takes a lot of time and there's a decent chance of producing a hydrological network that's completely different from what I had before. Detailing an existing terrain can be more work than producing a new one. Ask any of the people making the rivers run through Middle-Earth .

If you ever find a way to get labeling or annotation to show up in ArcScene, let me know.