Terrain Paint is a sandbox mode accessible from the "Change mode" menu in the top right corner of the sandbox, visible when advanced options are shown. The terrain paint mode allows you to draw and edit terrain in the sandbox.
The terrain will look identical to the Block objects, but they stick together as a cohesive terrain piece and cannot be interacted with as regular objects. The terrain paint mode can also be used to modify the Procedural Terrain generated in a procedural adventure level.
While in terrain paint mode, clicking and dragging on the screen will always draw or erase terrain. On desktop, you can use the middle mouse button to pan the camera around while in terrain paint mode.
In the bottom-left there are options to select what layers will be affected by the terrain paint mode. With layer inclusion enabled, it will paint across the selected amount of layers (denoted with a plus), while with layer exclusion disabled it will only paint on the selected layer.
The terrain paint mode has a few different brushes to choose from:
The adventure robot can mine all of these terrain types with the Zapper, with each type being tougher to mine.