Working with Geometry
Creating geometry is crucial for both 2D and 3D maps. We have 3 different types of geometry in Eldiron:
- Vertices are points in the map.
- Linedefs are lines between the points.
- Sectors are a series of linedefs which form a closed polygon.
The terms Linedefs and Sectors are based on the game Doom, which used the same terminology.
You can apply tiles only to sectors, for example via the Apply Tile button in the Tile Picker dock or by using the Rect tool.
Creating Sectors
To create a sector we use the Linedef tool.

When you click on grid positions, the Linedef tool automatically creates new vertices and linedefs between those points. Clicking the starting vertex again closes the polygon.
Here we selected the Sector tool to select the newly created sector.

By default the linedef tool is in manual mode, meaning you have to click every vertex position to create a sector, even if some of the vertices already exist.
When you hold Cmd/Ctrl while clicking the tool tries to auto-close existing polygons on every click, so you just need to click on the vertices you want to connect to close a polygon.
Applying a Tile
Now we can apply a tile to the sector using the Apply Tile button in the Tile Picker dock. It applies the currently selected tile in the tile picker to the currently selected sector.

The Rect tool does all the above in one step, it creates a rectangular sector and applies the currently selected tile to it, but it is only used for decoration purposes (i.e. quickly drawing tiles). When you want to create the foundations of an area (for example a house), you need to create its sector manually.
Other Functions
The Vertex, Linedef and Sector tools have a diverse set of functionality, so make sure to read their documentation. You can, for example, create new standalone vertices with the vertex tool by holding Shift and clicking in the grid.
3D Geometry Modes
In 3D views, Eldiron has two geometry edit modes in the HUD:
GEOM: edit world geometry directly.DETAIL: edit the active surface profile directly in 3D.
GEOM is used for structural edits such as moving vertices, building sectors, and extruding geometry.
DETAIL is used for surface-local edits such as holes, windows, gates, recesses, and reliefs. In this mode you click a wall, floor, or ceiling and the Vertex, Linedef, and Sector tools operate on that surface profile instead of on the world map.
Using each tool you can select and drag the corresponding geometry, both in 2D and 3D. In GEOM, 3D camera views show a small gizmo helper at the bottom right of the viewport to control in which plane you are dragging the geometry:

In DETAIL, the active surface defines the editing plane, so the plane gizmo is hidden.
Press Delete to remove the currently selected geometry.
All geometry editing operations are undoable.