ProFantasy Software produces expansions for CC called add-ons. They do not work without CC. Add-ons furnish you with new tools for a dedicated purpose. They give CC more mapping muscle.
It's best to use an example. Say you wanted to devise a town with just CC. You start with a blank map, add roads, then select buildings from a symbol library, and then place them. Add labels, and you have a pretty nifty town. Now, imagine you have City Designer Pro as well. You start with the same road layout, but you have a choice of 1500 symbols in an array of styles, which you can slide around your roads. You can create buildings of any shape or size with a few clicks or even create whole random streets on the fly. When you've labeled your maps, City Designer Pro can add an alphabetical street index with coordinates. Click on a street name, zoom to the street. And this is just a sample of what CD Pro can do. Add-ons gives you more options, and lets you build your city faster.
The add-ons are separate from CC because we want to give you a choice - if you don't need card models, don't get Dioramas Pro; if you rarely create urban areas, you don't need CD Pro. If you have CC, and need to expand your campaign, you can get the appropriate add-on. All the add-ons benefit from the powerful features of CC's CAD engine, and you can use any add-on with any design.
We also offer symbols sets - collections of extra artwork to make your maps more distinctive and attractive. Symbol Set 1 contains fantasy overland symbols in two styles with variations; Symbol Set 2 adds new variety to your fantasy floorplans, and Symbol Set 3 lets you create modern overland maps and floorplans with a huge collection of symbols. They plug in neatly and are easy to use.