I haven't had a chance to try Don's recommendation, as that takes a bit more than changing the fill style for the part that's behind the gray shading for the dome, but I have tried Sue's approach and I'm really happy with it. Right now, there's not much on this demo, but once I add a full fortress, we'll see whether the blurs slow things down too much.

I won't post all of the examples I tried. I did a lot, using fills from both Dungeons and Cities of Schley, DD3, Beaumaris Castle, and even Cosmographer just to see what it would look like with concrete and metal fills.

Here it is with a few Schley fills (the second one wouldn't work because it doesn't look like construction, but it does show the effectiveness of the technique):

I found that the best-looking fills were ones that had enough texture to hide the banding from the dome bands, but not so much texture that the doming effect was obscured. For the banding issue, that can be mitigated by reducing the opacity, but at the expense of losing some of the doming effect. Trade-offs! Here's an example using a 95% opacity versus a 50% opacity.

And it works with tiles and wood planks, too -- not suitable for what I'm designing, but useful to remember for future projects.

Here are my two favorites -- the second one isn't really suitable for this project, but looks really cool. Raw Granite, and Roof Lead, both from Beaumaris Castle.

And here's a quick mockup of how it might look with the rest of the roof. I added strips of the Stone Paving Brown on the edges of the barrel dome, for the part of the façade if you look at the source inspiration. This is just a sample -- the full roof will have towers, crenellations, a line down the barrel dome to show it's retractable, and more.

Thank you! I learn a lot by studying other people's approaches. Ralf once did a tutorial (for Marine Dungeons 2) where he hid every sheet and then unhid each one, one by one, to show what was on the sheet and how the effects on that sheet worked. It was very helpful and I now do the same thing from time to time when I can if I'm trying to learn from someone's new approach.

It looks good! First I tried it with 10-foot wide, 10 degree pitch increments, with a 80 degree pitch at the edges, working up to a 10 degree pitch at the center. The transitions were a little sharp:

Then I redid it with a more gradual transition, 5-feet wide sheets with 5 degree pitch increments going from 85 degree pitch at the edges to 5 degrees at the center. That worked much better! Some fill styles worked better than others, of course -- though some that I didn't care for might be improved if I play with adjusting the scaling. Roof tiles didn't really work very well, but wood worked, as did different stone fills. Here are the top 50% of my experiments:

Thank you for the tip, Sue! I can play with fills (and the scaling of those fills), but I feel like I have something solid to work with here.

One of the projects I'm working on is an attempt to create a fortress loosely modeled after The Armory in San Francisco (here are some pix I took nearly a decade ago, so no copyright violation posting them):

After a bit of research, I've learned that the dome-shaped part of the roof is actually called a barrel roof. In my version, the roof would be split in the center and retractable, allowing for flying creatures housed inside to be able to fly in and out when the roof is retracted.

I've been trying to create the barrel roof using a variety of techniques and effects, but I'm not super thrilled with all of my results. First, I tried taking domes from City Domes and enlarging with different XY values to make them oval. I like how it looks, but for a different project. Not the barrel roof I'm looking for.

I tried adding walls at the ends to chop off the ends, but it's still not a barrel roof.

Then I tried something totally different: going for two rectangular polygons with the Shaded Polygon (Angled by Edge) effects, as if going for a peaked roof, and then adding a series of Glow effects to suggest curvature. There are three Inner Glow effects on this, with a Blur of 4, 8, and 16 map units:

This is getting closer, but I would love any suggestions with effects or an entirely different approach to achieve a proper barrel roof. Here's the FCW for the latest attempt, if that helps.

I'm sure ProFantasy has a communication plan as part of their scheduled release, and all announcements are carefully scheduled as part of that plan, and we won't know anything until all of the logistics are sorted out...but I am dying to know when CC4 will be released.