Walls, Scroll, and Collision¶

Walls, scroll limits and collision shapes decide where characters can move and how far the camera advances. Together they define the playable space, which is separate from — and easy to get out of step with — the background art.

Walls¶

Setting	Effect
Left Wall	Blocks the left side of the scene so the player cannot walk past it.
Right Wall	Blocks the right side.
Vertical Left	Makes the left wall run straight up and down instead of slanting with the floor. Only available while Left Wall is on.
Limit X	The horizontal position, in pixels, at which a wall limit takes effect.
Diagonal Limits	Slanted boundaries of the walkable area, for scenes whose walls are not square to the screen.

Walls are what create closed-room encounters, stop players at scene edges, and keep enemies inside the intended combat area.

Vertical Left is the setting people miss. By default a wall slants to follow the floor's perspective; turning it vertical is what you want for a genuine flat surface such as a lift wall or a door frame, where a slanted boundary looks wrong as the player walks up and down.

Diagonal Limits exist for scenes built at an angle — alleys, ramps, bridges — where a rectangular walkable area would either cut off usable floor or let characters walk into the scenery.

Scroll Limits¶

Scroll limits control how far the camera advances before the scene stops or transitions. A scene has an X limit and diagonal scroll limits.

When a scene feels too short, too long, or transitions early, check the scroll limits before you touch the art. This is almost always the cause, and it is a much smaller fix than re-cutting a background.

Custom Collision Shapes¶

Where simple wall limits are not enough, custom shapes define collision from a list of points.

Setting	Meaning
Points	The corner points, in pixels. The shape is drawn by joining them in order.
Closed	Joins the last point back to the first, making a closed outline rather than an open line.
Collision Side	Which side of the shape blocks movement.

Use custom shapes for slopes, irregular boundaries, stage-specific blockers, and anything a rectangle cannot describe.

Collision Side is the field to check first when a shape appears to do nothing, or blocks from the wrong direction — the geometry is usually right and the side is backwards.

Pits¶

Pits use the same point-list model, plus Pit Damage: the damage taken by anyone who falls in. Setting it to 0 makes the pit harmless, which is useful for purely visual gaps or for a pit that only inconveniences.

Walls have Max Height and Stops Knockdowns. With Max Height at 0 the wall blocks at any height. Above 0 it only blocks entities lower than that many pixels above the ground, like a rail or a low fence: walking characters stop, while jumps high enough pass over it and thrown characters always do. Tick Stops Knockdowns to also catch knocked-down characters (including script-driven knockdowns) at any height, so a knockdown never flies over the rail (for example, a rail in front of a pit).

The interaction rule is worth stating explicitly: grounded players, enemies and items always collide with pit boundaries, but airborne objects can still fall through when there is no ground beneath them. So a character knocked into the air over a pit will drop into it, while one walking is stopped at the edge.

Treadmills¶

A shape can carry a Treadmill Velocity — the speed it pushes anyone standing on it, along the horizontal and depth axes. This drives conveyor belts and moving floors.

Editing in the Preview¶

The preview shows wall handles, scroll ranges, collision lines and scene objects. Handles stay a constant size on screen regardless of zoom, so you can zoom right out to set a scroll range and right in to place a collision point.

Drag for the broad shape, then correct exact values in the Inspector.

Testing¶

Still previews hide collision problems. Test in gameplay and specifically with movement that leaves the ground: jump arcs, throws, and knockbacks are what find gaps in walls, pits that catch when they should not, and diagonal limits that stop short.

Related pages: The Level Editor Workspace, Scene Settings, Spawns, Background Layers. round-layers.md).