From their website:
WorldWorksGames continues to break new ground with its TerrainlinX system by offering users an entirely new way to plan their layouts. Organize, Plan, Layer, Build, Share.
Organize: The TerrainlinX model planner organizes all TerrainlinX compatible modelsets in a drop-down interface. New planner tile sets will be added for free as each new TerrainlinX modelset is released.
Plan: An intuitive user interface and common sense tools allow you to manipulate tiles, walls, posts, balconies, stairs, ramps and generic gaming markers. In no time you’ll be designing your layouts quickly and easily.
Layer: A groundbreaking layers system allows you to clearly define each stacking level of your TerrainlinX layout. Design your multilevel terrain to interact in astounding ways. Add as many layers as you like, view lower and upper layers with a user defined transparency as you build.
Build: The TerrainlinX planner builds a dynamic manifest of the items based on your layout, telling you which PDF page to print from and how many pages you’ll need to print to start your build. Its like having a WWG build tutor on your computer.
Share: Save your layout as a freely editable planner file or PNG image file, to share with others or to collaborate. Click the “community” button to access full planner support, future feature requests and of course to share and show off your TLX layouts.