Double Dash: a custom track

Before you start

This tutorial takes a Mario Kart: Double Dash!! track from a 3D model to racing it in Dolphin. You need your Double Dash disc linked and its tools turned on in Settings > Games, Dolphin installed, and a model of your track exported as .obj or .dae. If you've made a Mario Kart Wii track, most of this will feel familiar: the editors are the same.

A Double Dash track is a slot's .arc archive (for example Luigi2.arc for Luigi Circuit), plus a multiplayer copy ending in L.arc. Inside, with the slot's file prefix:

• luigi_course.bmd: the model you see.
• luigi_course.bco: collision.
• luigi_course.bol: start, enemy route, checkpoints, respawns, objects and cameras.
• luigi_map.bti: the minimap, a picture of the road.
• luigi_sky.bmd: the sky (optional).
• objects/: models for the track's objects.

Each slot's minimap area is fixed in the game itself, which is why the app reads it from your disc.

1. Prepare the model

1. Name your materials after what they are. The app guesses each surface from its material name: grass or offroad is off-road, sand, dirt, mud, gravel, ice and snow are what they say, wall, fence, rail or barrier is a wall, water, lava or void is a fall, boost or dash is a boost, ramp or jump is a ramp, and anything else is road.
2. Keep it under about 15,000 triangles, the busiest retail track. Textures are shrunk to fit the GameCube's memory for you.
3. Export a sky model too if you want one.

2. Build the track

1. Choose File > New > Mario Kart: Double Dash!! > Track from Model....
2. Pick the slot it Replaces (Luigi Circuit is a good first choice), your track model and, optionally, the sky model. Leave Scale at 1 unless your model is the wrong size.
3. Press Create and choose a folder. The slot's archives are written there, with a start point on the road, an intro camera, collision and a minimap. The console lists what was made and what's still missing.

3. Check the collision

1. Double-click the .arc to open it, then open *_course.bco.
2. Check every surface in the list is what you meant. Select a triangle to retag everything connected to it, and make sure walls are walls and anything you can fall into is a fall.

More in Mario Kart Wii tracks: the collision editor works the same way.

4. Course data

Open *_course.bol. The track model and collision load behind the canvas on their own.

1. Start point. Already on the road: drag it onto your start line and turn it to face the way you race.
2. Enemy route. CPU karts follow it. Pick the pen tool, click along the racing line all the way round and press Finish. Right-click points to add more before or after them.
3. Checkpoints. Draw them with the pen tool too, across the whole road, in driving order. Double Dash freezes while loading if the shape between two checkpoints bends, so keep them evenly spaced on curves.
4. Item boxes. Right-click empty canvas and choose Add Object Here, then set its type to GeoItemBox. Press ⌘D to place more.
5. Objects. Any other object works the same way. If its models aren't in the track, a banner imports them into objects/ from your disc.
6. Cameras. Tools > Intro Cameras... edits the opening fly-over.
7. Snap to Ground. Select everything with a marquee and choose Snap to Ground.
8. Check it. Press Check Laps: it lists anything Double Dash can't cope with. Make Testable fixes most of them.

5. Minimap, shadows and budget

1. The minimap was drawn from the collision. To redraw it (after changing the collision, or scaling), right-click the .arc and choose Mario Kart: Double Dash!! > Minimap Editor..., and tick the surfaces that belong on it.
2. For shadows, choose Mario Kart: Double Dash!! > Create Shadow Map.... Move the sun and watch the live preview; the shadows are baked into the model's vertex colours, the way retail tracks are lit.
3. Open *_course.bmd to see its Track Budget next to every retail track.

6. Drive it

Right-click the .arc and choose Mario Kart: Double Dash!! > Edit Track in 3D... to look round the track and drive the route before going near the emulator.

7. Play it

1. Right-click the .arc and choose Mark for Hot Swap > Mario Kart: Double Dash!! > Tracks, then a cup and the track to replace. Its files are renamed for that slot, so any of your track archives can go in any slot.
2. Press Run. The first time, choose your Double Dash disc as the base disc.
3. Before Dolphin starts, the track is checked. Errors stop it, each with what to do; press Auto Correct where it's offered to fix it for you.
4. Dolphin boots a patched copy of your disc; the original is never changed. The same copy runs in Nintendont on a real Wii or GameCube.

More in Testing your mod.

If it freezes

• Run Check Laps: a bent checkpoint quad freezes the game while the track loads.
• Every enemy route group must join another at both ends, so the route loops. Make Testable joins them to the nearest.
• Parts of the track outside the slot's minimap area don't show on it. Scale the track or pick a slot with more room.
• Too many triangles slows the game down, especially in split-screen. Check the Track Budget.

Next: a Double Dash battle arena, or the Double Dash reference.