After posting this in response to a question from a user on the Profantasy Forum, Gandwarf suggested that I post it here as well.
Here's a quick and easy way to generate a floating landmass using simple sheet effects in CC3. This is very rough and basic and is only to be used as starting settings for anyone trying to accomplish this effect.
Floating Landmasses can best be acheived through the use of SHEET EFFECTS. Regardless of which style pack you choose, you'll need to create a SHEET EFFECT that produces the result you're looking for. The 'Drop Shadow' effect will produce a shadow under your continents to give the appearance of floating. You'll need to experiment with the settings to get the right distance under your landmasses.
If you want every Landmass to be floating at the same elevation then I would suggest using any of the map templates that start with an Ocean Background color and then adding the 'Drop Shadow' effect to the LAND SHEET. I would also apply a 'Blur' to the Background SHEET to make it look less like water. I used the Ice.bmp fill style with a Blur of 20 for my example map.
If you want the Landmasses to be floating at different elevations then you simply Add SHEETS called anything like "Landmass Low", "... Mid", "... High" or "...1", "...2", "...3" whatever makes sense to you and then use the "Move Up" button to position them directly under the BACKGROUND SHEET in the SHEET order list.
You can add as many as you wish, however it's VERY important to remember a few things. First is that CC3 draws things in your map in SHEET order from the TOP of the LIST to the BOTTOM. In our example above, everything on the BACKGROUND SHEET is drawn first. Everything on the LANDMASS 1 SHEET is drawn next. Then comes "...2" and "...3". IF I were to put a Square on my Background, a Circle on Landmass 1, a Triangle on Landmass 2, and some text on Landmass 3 the result would be Text on top of a Triangle on top of a Circle on top of a Square.
Here's a great thread that may help you to understand the way CC3 utilizes SHEETS
The second thing to remember is that SHEETS with nothing on them are deleted when you Save your map. If you erase a landmass from LANDMASS 2 (and there's nothing else on that SHEET) then the next time you Save your map, the LANDMASS 2 SHEET will be erased from your list resulting in a SHEET ORDER that looks like;
This has happened to me on many occasions after spending quite a bit of time getting my SHEET EFFECTS just right and then deleting the objects on the sheet right before a save.
For the landmass examples below I used 5 different LANDMASS SHEETS and varied the x,y DROP SHADOW effect 10,20,30,40 and 50 for each sheet.