Mario Kart Wii: a battle arena

Before you start

A battle arena is built like a race track (do the custom track tutorial first), with different course data. It's still one .szs holding course_model.brres, course.kcl, course.kmp, map_model.brres, vrcorn_model.brres and itembox.brres (copied from your disc when you place item boxes).

What every retail arena has, and yours needs:

• 12 start points, one per player, numbered 0 to 11 (a race track has one).
• 4 battle respawn points (MSPT).
• Respawn points (JGPT), usually 12.
• A CPU network of enemy points, many small linked paths.
• No checkpoints and no item paths.
• Item boxes, and for Coin Runners, coins (72 to 134 on retail arenas).

1. Model, collision, minimap and sky

1. Open a folder, export your arena as course_model.obj and build course_model.brres with Make .brres, exactly as in the track tutorial.
2. Make course.kcl with File > New > Collision (KCL) from Model.... Arenas are enclosed: make the outer walls walls, and anything you can fall into a fall boundary.
3. Make the minimap with Mario Kart Wii > Minimap Editor... and the sky with File > New > Skybox.
4. Optionally bake shadows with Mario Kart Wii > Create Shadow Map... on the track model.

2. Battle course data

1. Choose File > New > Battle Arena Course Data (KMP)..., save it as course.kmp and open it. It starts with the 12 starts, 4 battle respawns, 12 respawns and a CPU loop a working arena needs.
2. Load your track model and collision behind the canvas with Auto-Detect.
3. Drag the 12 start points round the arena, spread out and facing inwards. Keep each one's player number; the inspector shows it.
4. Place the 4 Battle Respawn Points (MSPT) in safe open spots. Right-click a point for Duplicate, Snap to Ground and Delete.
5. Draw the CPU network with the pen tool: several short enemy paths that link up so CPU racers can roam the whole arena. Right-click points to add more before or after them.
6. Add item boxes as Object (GOBJ) points, and coins (object 0x73) if you want Coin Runners to work. Duplicate on the right-click menu places them quickly.
7. Select everything and Snap to Ground.
8. Check the editor's header says Battle Arena: that means the course data is recognised as an arena, so Tools > Make Testable and Verify Archive use the battle rules. Run Make Testable to fill in anything missing (start numbering, battle respawns, respawns).

3. Pack and play

1. Put the six files in a folder (or an .szs made with File > New > SZS Archive...) and press Verify Archive with the type set to Custom Battle Arena.
2. Right-click it and choose Mark for Hot Swap > Mario Kart Wii > Battle Maps, then the arena to replace (Block Plaza is a good first choice).
3. Press Run. The checks before Dolphin starts won't let an arena run on a race track's slot, or a race track on an arena's slot, and list anything else likely to crash.
4. Start a Balloon Battle or Coin Runners on the arena you replaced.

More in Testing your mod and Mario Kart Wii tracks.

If it crashes

• Make sure there are exactly 12 start points numbered 0 to 11, and 4 battle respawns. Make Testable fixes both.
• An arena has no checkpoints. Add one and its course data is treated as a race track's, and the checks before playing will stop it running on an arena slot.
• Every arena needs itembox.brres in the archive, and Coin Runners needs coin.brres too. The missing-files banner copies them from your disc.