Cascade

How to make an osu!mania map online

You don't need to install osu! (or even own a PC that runs it) to start mapping. This guide walks through making a playable osu!mania beatmap entirely in the browser with Cascade, from a bare audio file to an exported .osz.

1. Load your song

Drag an .mp3 or .ogg onto the page. The song appears in the bottom timeline as a waveform. If you already have a map you want to improve instead, drop the whole .osz.

2. Set BPM and offset

Open the Timing panel. If you don't know the BPM, use tap tempo: play the song and tap along, and Cascade averages your taps. Set the offset so the first beat lands on a barline, then turn on the metronome to check it. Getting timing right first matters more than anything else: every note you place snaps to this grid.

3. Place notes

• Click a lane to place a note; click and drag upward for a long note (hold).
• Pick a snap divisor (1/4 for most rhythms, 1/6 and 1/8 for triplets and bursts).
• Press Space to play back what you have; scrub with the mouse wheel.
• Copy, paste and mirror selections to build patterns faster, or start from the built-in pattern presets.

4. Polish

• Add hitsound additions (whistle, finish, clap) to accent the rhythm.
• Set a background image or a muted background video in Map Settings.
• Use Playtest mode to actually play your chart with judgements and accuracy, then fix what feels wrong.
• Add more difficulties to turn the map into a full spread.

5. Export

File → Export .osz packages the audio, background, video and every difficulty into one file you can drop straight into osu!. You can also export a single .osu, or convert the map to StepMania / Etterna as .sm.

Tips for your first map

• Map a song you know well; predictable rhythm is easier to chart.
• Follow the music, not the maximum note density you can play.
• Keep patterns consistent: similar sounds should produce similar shapes.
• Watch your map in the map viewer at 50% speed to spot mistimed notes.