Rhythm and structure

How to map the music, why beat segments have holes in them, and why the level has to peak where the track does

A rhythm game rests on one sensation: the player is not moving to the music, they are playing it

The beat grid

The beat grid is for you, not for the game. Playback never reads it. You use it to place content on the music, and generators act on the same beats

The grid is made of segments. A segment is a stretch of constant tempo, and there can be several. Between segments there can be holes: an intro with no percussion, a break, the tail after the last note

Map only the stretches that will carry content. An intro usually needs nothing

Finding the tempo

Find the bpm
Then the offset
Then the beats per bar

The bpm is unknown? Tap it in along with the track in the Beat Grid window (Shift+T). Round it to a whole number and fix the rest with the offset

A track is almost always written on a whole bpm. A fractional value usually means the offset is wrong rather than the tempo

Mapping the sound

Split the instruments across different kinds of content:

the kick - under whatever requires action from the player
secondary hits - under motion that requires nothing
long pads and atmosphere - under the background and the camera

Then the level sounds like it has depth instead of hitting one beat with everything

The size of a movement carries the strength of a sound. Small movement, weak hit. Large movement, strong hit. A big effect on a weak note reads as a sync error even when the frames are exact

The shape of a movement carries the accent. A sharp turn stresses a strong note, a smooth curve a weak one

In 4/4 the beats rank 1, 3, 2, 4. An action on the first beat is the most intuitive there is. Syncopation gives groove. But syncopation used often or inconsistently stops the player knowing where they are

An odd meter is split into groups the player can count. In 7/4, groups of 4+4+2+2+2 are easier to follow than 4+4+4+2

Structure

Sections are what a player remembers. A level without them is four minutes of the same thing, even when something new happens every five seconds

Repetition teaches. A pattern that comes back is recognised and learned faster. Too much of it bores, and breaking an established pattern for no reason reads as carelessness rather than as variation

Recommendation

Put markers on the track's structure before placing the first object: intro, verse, chorus, break, drop, outro. They show on every timeline and cost nothing

Caution

The level's peak has to land on the track's peak, and rests are mandatory. A break is where the player breathes. A level with none exhausts people before it gets difficult

The ending is designed too: either a final peak or a calm fade-out. A level should not simply stop

Why segments rather than keys

The beat grid is a list of stretches, not a track of keys. A key track cannot express absence: its last key would reach to the end of the level. And segments need holes between them

Next: Frames, time and the length of a level, Difficulty and the curve