AttributesSerialize.md

Instance AttributesSerialize format

This document describes the binary format of the Instance.AttributesSerialize property.

Type notation

The following primitive types are defined for use throughout this document:

Type	Example	Description
intN	int32	A signed integer with a size of N bits. Little-endian encoding.
uintN	uint8	An unsigned signed integer with a size of N bits. Little-endian encoding.
floatN	float32	A IEEE 754 floating-point number with a size of N bits. Little-endian encoding.
[N]T	[9]float32	An array of constant length N, with elements of type T.
[]T	[]uint8	An array with elements of type T, the length of which is determined dynamically.
?T	?uint32	A value of type T, which may or may not be present based on some condition. If not present, the value is omitted entirely.
...	...	The type is determined dynamically.

A type may also be a named type defined elsewhere in the document.

Structures

A "structure" type comprises a number of ordered fields, each having a certain type. This document describes structures by using a table with Field, Type and Description columns. The Field column contains a name that identifies the field. The Type column contains a type as described above. The Description column contains a description of the field. Each row of the table is a specific field. When decoding or encoding, each row is read or written in order, top to bottom.

Format structure

The attributes format consists of one Dictionary value, which maps attribute names to values.

Several limitations may be applied to the Key field of an Entry in this Dictionary:

• Must not have a length greater than 100 bytes.
• May only contain alphanumeric bytes and underscores. (^[0-9A-Za-z_]*$)
• Must not begin with RBX, which is reserved for Roblox.

Dictionary

The Dictionary type represents a collection of keys mapped to values. It is a structure with the following fields:

Field	Type	Description
Length	uint32	The number of entries in the dictionary.
Entries	[]Entry	The entries of the dictionary. The length is determined by the Length field.

Entry

The Entry type represents a single key-value pair from a Dictionary. It is a structure with the following fields:

Field	Type	Description
Key	String	The key of the entry.
Value	Value	The value of the entry.

Value

The Value type holds a value of one of a number of types. It is a structure with the following fields:

Field	Type	Description
Type	uint8	An identifier indicating the value's type.
Value	...	Type determined by the Type field.

The following table describes the identifier's corresponding type:

Type ID	Type
2	String
3	Bool
5	Float
6	Double
9	UDim
10	UDim2
14	BrickColor
15	Color3
16	Vector2
17	Vector3
20	CFrame
23	NumberSequence
25	ColorSequence
27	NumberRange
28	Rect

Other IDs are reserved for future use.

Value types

String

The String type corresponds to the "string" Roblox data type.

It is a structure with the following fields:

Field	Type	Description
Length	uint32	The length of the string, in bytes.
Content	[]uint8	The content of the string. The length is determined by the Length field.

Bool

The Bool type corresponds to the "bool" Roblox data type.

Type: uint8

A value of 0 represents false, while 1 represents true. Any other value may be interpreted as true.

Float

The Float type corresponds to the "float" Roblox data type.

Type: float32

While Studio is not capable of producing attributes of the Float type (Double is used for numeric types), it does accept the type when decoding.

Double

The Double type corresponds to the "double" Roblox data type.

Type: float64

UDim

The UDim type corresponds to the "UDim" Roblox data type. It is a structure with the following fields:

Field	Type	Description
Scale	float32	Corresponds to UDim.Scale.
Offset	int32	Corresponds to UDim.Offset.

UDim2

The UDim2 type corresponds to the "UDim2" Roblox data type. It is a structure with the following fields:

Field	Type	Description
X	UDim	Corresponds to UDim2.X.
Y	UDim	Corresponds to UDim2.Y.

BrickColor

The BrickColor type corresponds to the "BrickColor" Roblox data type.

Type: uint32

Color3

The Color3 type corresponds to the "Color3" Roblox data type. It is a structure with the following fields:

Field	Type	Description
R	float32	Corresponds to Color3.R.
G	float32	Corresponds to Color3.G.
B	float32	Corresponds to Color3.B.

Vector2

The Vector2 type corresponds to the "Vector2" Roblox data type. It is a structure with the following fields:

Field	Type	Description
X	float32	Corresponds to Vector2.X.
Y	float32	Corresponds to Vector2.Y.

Vector3

The Vector3 type corresponds to the "Vector3" Roblox data type. It is a structure with the following fields:

Field	Type	Description
X	float32	Corresponds to Vector3.X.
Y	float32	Corresponds to Vector3.Y.
Z	float32	Corresponds to Vector3.Z.

CFrame

The CFrame type corresponds to the CFrame Roblox data type. It is a structure with the following fields:

Field	Type	Description
Position	Vector3	The position portion of the CFrame.
ID	uint8	A value representing a prefined rotation matrix.
Rotation	?[9]float32	The rotation portion of the CFrame. Present only if ID is 0.

The indices of the rotation array correspond to the following matrix elements:

Right	Up	-Look
0	1	2
3	4	5
6	7	8

Or, expressed as a CFrame constructor:

CFrame.new(_, _, _, 0, 1, 2, 3, 4, 5, 6, 7, 8)

Rotation IDs

The following IDs must produce the corresponding rotation matrix. Non-zero IDs that aren't in this list are undefined.

0x02 : [+1 +0 +0 +0 +1 +0 +0 +0 +1]
0x03 : [+1 +0 +0 +0 +0 -1 +0 +1 +0]
0x05 : [+1 +0 +0 +0 -1 +0 +0 +0 -1]
0x06 : [+1 +0 -0 +0 +0 +1 +0 -1 +0]
0x07 : [+0 +1 +0 +1 +0 +0 +0 +0 -1]
0x09 : [+0 +0 +1 +1 +0 +0 +0 +1 +0]
0x0A : [+0 -1 +0 +1 +0 -0 +0 +0 +1]
0x0C : [+0 +0 -1 +1 +0 +0 +0 -1 +0]
0x0D : [+0 +1 +0 +0 +0 +1 +1 +0 +0]
0x0E : [+0 +0 -1 +0 +1 +0 +1 +0 +0]
0x10 : [+0 -1 +0 +0 +0 -1 +1 +0 +0]
0x11 : [+0 +0 +1 +0 -1 +0 +1 +0 -0]
0x14 : [-1 +0 +0 +0 +1 +0 +0 +0 -1]
0x15 : [-1 +0 +0 +0 +0 +1 +0 +1 -0]
0x17 : [-1 +0 +0 +0 -1 +0 +0 +0 +1]
0x18 : [-1 +0 -0 +0 +0 -1 +0 -1 -0]
0x19 : [+0 +1 -0 -1 +0 +0 +0 +0 +1]
0x1B : [+0 +0 -1 -1 +0 +0 +0 +1 +0]
0x1C : [+0 -1 -0 -1 +0 -0 +0 +0 -1]
0x1E : [+0 +0 +1 -1 +0 +0 +0 -1 +0]
0x1F : [+0 +1 +0 +0 +0 -1 -1 +0 +0]
0x20 : [+0 +0 +1 +0 +1 -0 -1 +0 +0]
0x22 : [+0 -1 +0 +0 +0 +1 -1 +0 +0]
0x23 : [+0 +0 -1 +0 -1 -0 -1 +0 -0]

NumberSequence

The NumberSequence type corresponds to the "NumberSequence" Roblox data type. It is a structure with the following fields:

Field	Type	Description
Length	uint32	The length of the sequence.
Keypoints	[]NumberSequenceKeypoint	The keypoints of the sequence, the length determined by the Length field.

NumberSequenceKeypoint

The NumberSequenceKeypoint type corresponds to the "NumberSequenceKeypoint" Roblox data type. It is a structure with the following fields:

Field	Type	Description
Envelope	float32	Corresponds to NumberSequenceKeypoint.Envelope.
Time	float32	Corresponds to NumberSequenceKeypoint.Time.
Value	float32	Corresponds to NumberSequenceKeypoint.Value.

ColorSequence

The ColorSequence type corresponds to the "ColorSequence" Roblox data type. It is a structure with the following fields:

Field	Type	Description
Length	uint32	The length of the sequence.
Keypoints	[]ColorSequenceKeypoint	The keypoints of the sequence, the length determined by the Length field.

ColorSequenceKeypoint

The ColorSequenceKeypoint type corresponds to the "ColorSequenceKeypoint" Roblox data type. It is a structure with the following fields:

Field	Type	Description
Envelope	float32	Corresponds to ColorSequenceKeypoint.Envelope.
Time	float32	Corresponds to ColorSequenceKeypoint.Time.
Value	Color3	Corresponds to ColorSequenceKeypoint.Value.

NumberRange

The NumberRange type corresponds to the "NumberRange" Roblox data type. It is a structure with the following fields:

Field	Type	Description
Min	float32	Corresponds to NumberRange.Min.
Max	float32	Corresponds to NumberRange.Max.

Rect

The Rect type corresponds to the "Rect" Roblox data type. It is a structure with the following fields:

Field	Type	Description
Min	Vector2	Corresponds to Rect.Min.
Max	Vector2	Corresponds to Rect.Max.