Check out a tool to play tabletop RPGs online where you can create your own spaces.
Game developer Daniel F. Marques currently works on his new project called D&D Map Sketcher. The tool allows you to easily draw maps while playing. The latest update added animation to tile placement, which makes the building process even more satisfying.
Map Sketcher is in the open beta version now and includes essential features only.
On the website, you can find the controls section and how to use it. Definitely check it before starting working on the tool. There is also some advice on the general workflow in the tool.
Download the tool here.