Dirt and decals

Dirt (grime decals)

Properties > Interior > Dirt is the project’s default for every room. Select a room and open Dirt there to give it Own settings for this room. Nothing is on in a new project.

Kind	Where it goes
Floor edge	Scuffs and grime just above the skirting, fading upwards
Ceiling edge	Dust and soot under the cornice
Corners	Vertical streaks in both walls of every inside corner
Doors and frames	Darker near the frame; a hand mark at handle height beside a door’s latch
Window sills	Rain-like streaks under every window with wall below it
Light fittings	A soft soot halo on the ceiling round lights and ceiling props

Each kind has a Strength (0 to 1) and a Reach in metres. A room’s kinds share a Colour, Noise scale, Breakup (0 = smooth gradient, 100 = separate patches), Seed and Shuffle. The dirt follows openings, arcs, sloped ceilings, raised floors and every level. The floor edge and the ceiling edge run on under and over windows, also with a long reach or under a low window.

It is geometry, not a texture on the walls: thin quads a few millimetres in front of the surface with the gradient in their vertex alpha. The export writes them into the room’s details model on the game’s decal shader (draw bucket 2), never into the shell or its collision.

Free decals

Key	Action
Shift+B	Decal tool: a ghost of the chosen decal follows the pointer over walls, floors, ceilings, stairs and mesh objects; click to place it
R	Turn the ghost 15 degrees (Shift+R in the Blender keys)
[ / ]	Smaller / larger
Shift+wheel	Size
Alt+wheel	Turn

The strip over the view holds the picture, Width, Height, Turn, Opacity, the generator’s strength, Wrap and the colour. The seed moves on after every click, so the next decal is another stain.

The pictures are nine generators (a few numbers and a seed, so the project stores numbers, not images): water stain, crack, scuffs, soot / burn, grime patch, gradient (linear, radial or corner), mould, drips and footprints. Import image… takes a PNG, JPEG, TGA or DDS with its alpha, and a texture of the game works too.

Wrap bends a decal over inside and outside corners, floor edges and doorway reveals instead of stretching a flat rectangle across them.

Editing a decal

Select a decal (click where its picture shows, or in the Scene list). Properties has Picture, Size and turn and On the surface. The selection shows an outline with handles:

• the dot slides the decal over whatever surface is under the pointer;
• the two arrows slide it along its sides;
• the squares on its four sides resize it (the opposite side stays);
• the ring turns it, and the Scale tool’s handles resize it.

A decal outside every room is a problem and is not exported.

Mirrors

Tick Mirror at the top of a decal’s Properties and its rectangle becomes a mirror in the game, made the way the game makes its own: a reflecting quad (the mirror_default shader) in a model of its own in the decal’s room, and a mirror portal of that room on the same four corners. Place it, size it and turn it like any decal; it stays flat.

The view shows it silver: the reflection itself only appears in the game. A mirror on a wall and one on the floor are both possible.

A door in a doorway of the mirror’s room is written without the “don’t render in reflections” flag the game’s doors usually carry, as most of the game’s doors next to a mirror are, so the mirror can show it. This has not been checked in game yet.