Controls

Controls are an RPE feature that allows you to adjust various note parameters in a keyframe‑based manner.

Alpha Control

Field Name	Type	Description	Default Value	Version Added
easing	int	Easing type to the next keyframe value. See reference table.	1	–
alpha	float	Note opacity.	1.0	–
x	float	Vertical distance between the note and the judgeline.	–	–

• alpha control controls the opacity of notes.
• It can be used together with the note’s alpha field without conflict. The blending formula is: noteAlpha = noteAlpha * nowAlpha (after converting from 0–255 to 0–1).

Behavior

When alpha control is defined as follows:

{
  "alphaControl": [
    {
      "alpha": 1.0,
      "easing": 1,
      "x": 0.0
    },
    {
      "alpha": 0.5,
      "easing": 2,
      "x": 100.0
    },
    {
      "alpha": 1.0,
      "easing": 1,
      "x": 9999999.0
    }
  ]
}

• The note’s opacity is 0.5 until it is 100 y‑coordinate units away from the judgeline.
• After that, it eases to opacity 1.0 using the Out Sine easing function until it reaches the judgeline.

Size Control

Field Name	Type	Description	Default Value	Version Added
easing	int	Easing type to the next keyframe value. See reference table.	1	–
size	float	Note size multiplier.	1.0	–
x	float	Vertical distance between the note and the judgeline.	–	–

• size control truly controls the note’s overall size, not just its width.
• It can be used together with the note’s width field without conflict.
• Does not affect the size of Hold‑type notes.

Behavior

When size control is defined as follows:

{
  "sizeControl": [
    {
      "easing": 1,
      "size": 1.0,
      "x": 0.0
    },
    {
      "easing": 2,
      "size": 1.5,
      "x": 200.0
    },
    {
      "easing": 1,
      "size": 1.0,
      "x": 9999999.0
    }
  ]
}

• The note’s size is 1.5 times its original size until it is 200 y‑coordinate units away from the judgeline.
• After that, it eases to 1.0 times its original size using the Out Sine easing function until it reaches the judgeline.

pos Control (X Control)

Field Name	Type	Description	Default Value	Version Added
easing	int	Easing type to the next keyframe value. See reference table.	1	–
pos	float	Multiplier for the note’s positionX parameter.	–	–
x	float	Vertical distance between the note and the judgeline.	–	–

• pos control dynamically controls the multiplier for the note’s positionX.

Behavior

When pos control is defined as follows:

{
  "posControl": [
    {
      "easing": 1,
      "pos": 2.0,
      "x": 0.0
    },
    {
      "easing": 2,
      "pos": 1.0,
      "x": 100.0
    },
    {
      "easing": 1,
      "pos": 1.0,
      "x": 9999999.0
    }
  ]
}

• The note’s positionX is 2.0 times its original value until it is 100 y‑coordinate units away from the judgeline.
• After that, it eases to 1.0 times its original positionX using the Out Sine easing function until it coincides with the judgeline.

y Control

|:------😐:-----😐:----------------------------------------------😐:---😐:----😐 | easing | int | Easing type to the next keyframe value. See reference table. | 1 | – | | y | float | (To be documented) | – | – | | x | float | Vertical distance between the note and the judgeline. | – | – |

• Behaviors are to be documented.

Skew Control

Field Name	Type	Description	Default Value	Version Added
easing	int	Easing type to the next keyframe value. See reference table.	1	–
skew	float	(To be documented)	–	–
x	float	Vertical distance between the note and the judgeline.	–	–

• Has no effect on Hold‑type notes.
• Behaviors are to be documented.