Difference between revisions of "Motion (.MOT) File Format"

Revision as of 18:14, 7 September 2025

Note: This page pertains to Reverse Engineering of Okami File Formats.

Explanation

This file incorporates curves and/or properties for an given embbed model. Because of that, it's almost always certain that they are contained in a file container (dat). There's instances of mots that controlled properties instead of bones, so it's not always certain of what it animates. A further inspection have to be done. But since it animates bones most of the times, i will threat it as curves that animates bones.

Mot main header

Offset	Type	Size	Description
0x00	`uint32_t`	4	File identifier (Magic number).
0x04	`uint16_t`	2	Animation's frame count.
0x06	`uint8_t`	1	Animation's curve info count.
0x07	`uint8_t`	1	Loop flag, sets if the animation either loops or not (1/0).

on Offset 8, The File gives informations about the curves, i.e: what bone it animates, etc.

Curve Info

Offset	Type	Size	Description
0x00	`int8_t`	1	Bone index (-1 means it animates the mode's root bone).
0x01	`int8_t`	1	Curve properties (See below).
0x02	`uint16_t`	2	Curve keyframe count.
0x04	`uint32_t / float32_t`	4	Keyframes offset / value

the 4th offset of each curve info can be either a float, or uint32. it's only set as a float if the property family of the curve is a Single Pose. Otherwise, it's a offset. The curve property will define what property of the bone/object it is animating. There's some properties who could not be determined yet. See some already identified values bellow.

Curve Properties (Already identified)

Value	Property Family	Property
0	Single Pose	Position X
1	Single Pose	Position Y
2	Single Pose	Position Z
3	Single Pose	Rotation X
4	Single Pose	Rotation Y
5	Single Pose	Rotation Z
6	Single Pose	Scale X
7	Single Pose	Scale Y
8	Single Pose	Scale Z
16	Quantized Curve	Position X
17	Quantized Curve	Position Y
18	Quantized Curve	Position Z
19	Quantized Curve	Rotation X
20	Quantized Curve	Rotation Y
21	Quantized Curve	Rotation Z
22	Quantized Curve	Scale X
23	Quantized Curve	Scale Y
24	Quantized Curve	Scale Z
50	Semi-Precision Curve	Position X
51	Semi-Precision Curve	Position Y
52	Semi-Precision Curve	Position Z
53	Semi-Precision Curve	Rotation X
54	Semi-Precision Curve	Rotation Y
55	Semi-Precision Curve	Rotation Z
56	Semi-Precision Curve	Scale X
57	Semi-Precision Curve	Scale Y
58	Semi-Precision Curve	Scale Z
80	Full-Precision Curve	Position X
81	Full-Precision Curve	Position Y
82	Full-Precision Curve	Position Z
83	Full-Precision Curve	Rotation X
84	Full-Precision Curve	Rotation Y
85	Full-Precision Curve	Rotation Z
86	Full-Precision Curve	Scale X
87	Full-Precision Curve	Scale Y
88	Full-Precision Curve	Scale Z

The Property Family tells the game how the keyframes are handled ingame. Depending on the Family the property is set in, it can be readen diferently.

Single Pose

This Property Family is the cheapest to compute. Because since it's a single pose, The there's only one keyframe, in which is given on the Curve Info.

(Example):

Offset	Value	Description
0x00	-1	This field is telling that the curve is animating the root bone of the model.
0x01	5	This field is telling that the curve animates the Z rotation of the root bone, being set on a Single-Pose Property Family.
0x02	1	This field is telling that there's only one keyframe on this curve, which makes sense, since this curve is set on a Single-Pose Property Family.
0x04	0.52	This field is telling the value or the Z rotation right away, no more computing needed.

From now on, every single other curve are hermite curves. See more bellow...

Quantized Curve

This Property Family Is known for having Quantized values. It's the most eficient type of curve, regarding storage size.