Maya Spline

A Maya Spline is a 2D hermite curve first introduced in Metroid Prime 2: Echoes. It's used in various file formats to animate some sort of effect over time. It most commonly shows up in MREA files in script object properties, but it can also appear in other formats.

Format

Structure (Metroid Prime 2/3)

Type	Count	Name	Notes
u8	1	Pre Infinity	Infinity setting for time ranges before the start time of the spline curve.
u8	1	Post Infinity	Infinity setting for time ranges after the end time of the spline curve.
u32	1	Knot Count	Number of knots in the spline.
Knot	Knot Count	Knot Array	Array of knots forming the actual spline.
u8	1	Clamp Mode	Clamp mode setting.
float	1	Minimum Amplitude	Minimum amplitude used for clamped splines.
float	1	Maximum Amplitude	Maximum amplitude used for clamped splines.

Structure (Donkey Kong Country Returns)

Basically the same data as in Prime 2/3, but shifted around slightly.

Type	Count	Name	Notes
u32	1	Knot Count	Number of knots in the spline.
Knot	Knot Count	Knot Array	Array of knots forming the actual spline.
float	1	Minimum Amplitude	Minimum amplitude used for clamped splines.
float	1	Maximum Amplitude	Maximum amplitude used for clamped splines.
u8	1	Pre Infinity	Infinity setting for time ranges before the start time of the spline curve.
u8	1	Post Infinity	Infinity setting for time ranges after the end time of the spline curve.
u8	1	Clamp Mode	Clamp mode setting.

Knot

Offset	Type	Name	Notes
0x0	float	Time (X)	Time the knot is placed at; also serves as the knot's X position on the spline.
0x4	float	Amplitude (Y)	Amplitude of the knot; also serves as the knot's Y position on the spline.
0x8	u8	Unknown
0x9	u8	Unknown

Infinity Type Enum

This file format is almost completely documented Values are unknown but are probably similar to the values on this page.

Clamp Mode Enum

ID	Mode
0	Unclamped
1	Clamped between min/max
2	Unknown