Paint

In a 3D world the shape already exists and Paint dresses it, so the tool is a brush with materials in it. In a 2D world there is no shape to dress: the ground is a grid of cells, and painting is what decides which cells are ground at all.

Both are the Paint button in the tool column, and neither of them is the smaller job. Read the section that matches your project and ignore the other one.

Pick Paint and the strip under the view offers Texture, Blend, Auto, Colour, Wet and Dry. Texture lays the swatch you have selected. Blend mixes it into what is already there rather than replacing it. Auto hands the patch back to the ground, which then decides what it is made of by its slope and height. Colour paints the colour field instead of the material.

Wet and Dry work on how damp the surface reads, which is what makes a riverbank look like a riverbank rather than grass that happens to be next to water.

There is no verb that takes a colour off. White is no colour, so you clear a colour by painting white. Each stroke is one step of undo, and Ctrl+Z takes back the last one.

Drag to lay ground, and drag with the right mouse button to erase it. The strip has Paint and Erase and the brush size, from one cell to eight. That is the whole interaction. You are not drawing tiles one at a time and you are not picking which corner piece goes where — you are colouring in which cells are ground, and the tiles, the edges and the collision are all read back out of that.

The matching is ours and it is a pure function of the coverage, which has a consequence worth knowing: paint the same cells in a different order and you get the same world. Rebuild the project and your edges do not reshuffle. The sixteen drawn tiles it needs are cut from the nine pieces a tile pack already ships, so nothing has to be authored to make a new material work.

Whether the ground stops a walker is declared per material rather than assumed from the shape. A platformer's block and a top-down floor can be drawn with exactly the same strokes, and only one of them stops anybody. That is why the same tool serves both a side-on game and a game seen from above.

In a 3D world the panel on the right opens with Texture: a grid of swatches, first the materials this ground has, then every picture in your library, so a picture of your own can become ground. Pick a swatch, then paint. With Colour picked, a colour field with Hue, Saturation and Brightness sits under the swatches.

The same three sliders as Sculpt sit in the strip: Size, Strength and Falloff.

Advanced belongs to the 3D brush. Press it at the end of the strip and the panel adds a Slope range, exactly as Sculpt has, so you can paint only the steep faces or only the flat ground.

It also holds a toggle called "Only where it already is". With it on, a stroke strengthens the material where that material is already present and leaves the rest alone — the fastest way to tidy an edge without redrawing it.

When the ground offers them, Angle and Scale turn and size the material’s pattern. They control how the material is laid down rather than where.