Cast | A new open-source container for models, animations, and materials

The goal of cast is to create an engine agnostic format that can be parsed and written with ease. In addition, cast should have very similar output on any engine.

3D Engine Plugins:

• Autodesk Maya (Beta): Releases
• Blender (2.8+) (Beta): Releases
• 3DS Max: (Help wanted)

Programming libraries:

• .NET Framework: (Help wanted)
• Python: Libraries/Python
• C++: (Help wanted)

File stucture:

All files start with a cast header:

struct CastHeader
{
	uint32_t Magic;			// char[4] cast	(0x74736163)
	uint32_t Version;		// 0x1
	uint32_t RootNodes;		// Number of root nodes, which contain various sub nodes if necessary
	uint32_t Flags;			// Reserved for flags, or padding, whichever is needed
};

A cast file is basically a group of generic nodes. Nodes are given a unique registered id, which can tell the loader what the data is, and how to handle it.

Following the cast header is a collection of nodes which must be of type CastId::Root.

A node looks like:

struct CastNodeHeader
{
	CastId Identifier;		// Used to signify which class this node uses
	uint32_t NodeSize;		// Size of all data and sub data following the node
	uint64_t NodeHash;		// Unique hash, like an id, used to link nodes together
	uint32_t PropertyCount;	// The count of properties
	uint32_t ChildCount;	// The count of direct children nodes

	// We must read until the node size hits, and that means we are done.
	// The nodes are in a stack layout, so it's easy to load, FILO order.
};

There are several registered cast ids available:

enum class CastId : uint32_t
{
	Root = 0x746F6F72,
	Model = 0x6C646F6D,
	Mesh = 0x6873656D,
	BlendShape = 0x68736C62,
	Skeleton = 0x6C656B73,
	Bone = 0x656E6F62,
	Animation = 0x6D696E61,
	Curve = 0x76727563,
	NotificationTrack = 0x6669746E,
	Material = 0x6C74616D,
	File = 0x656C6966,
};

Following a node, is the list of properties [Node.PropertyCount], a property looks like:

struct CastPropertyHeader
{
	CastPropertyId Identifier;	// The element type of this property
	uint16_t NameSize;			// The size of the name of this property
	uint32_t ArrayLength;		// The number of elements this property contains (1 for single)

	// Following is UTF-8 string lowercase, size of namesize, NOT null terminated
	// cast_property[ArrayLength] array of data
};

For properties, cast has several built in types:

enum class CastPropertyId : uint16_t
{
	Byte = 'b',			// <uint8_t>
	Short = 'h',		// <uint16_t>
	Integer32 = 'i',	// <uint32_t>
	Integer64 = 'l',	// <uint64_t>

	Float = 'f',		// <float>
	Double = 'd',		// <double>

	String = 's',		// Null terminated UTF-8 string

	Vector2 = 'v2',		// Float precision vector XY
	Vector3 = 'v3',		// Float precision vector XYZ
	Vector4 = 'v4'		// Float precision vector XYZW
};

Parsing

To read a cast file, you just need to traverse the root nodes and their children. Properties always come before a nodes children. Each node has the total size of itself, and all children, so if a processor doesn't understand a node id, it can skip the entire node and continue reading.

Cast ids are integers for performance, unlike FBX where nodes are full strings.

Cast processors:

Model:

Field	Type(s)	IsArray	Required
Children	Skeleton, Mesh, Material	True	False
Parent	Root	False	True

Mesh:

Field	Type(s)	IsArray	Required
Children	None	True	False
Parent	Model	False	True

Property (id)	Type(s)	IsArray	Required
Name (n)	String (s)	False	False
Vertex Position Buffer (vp)	Vector 3 (v3)	True	True
Vertex Normal Buffer (vn)	Vector 3 (v3)	True	False
Vertex Tangent Buffer (vt)	Vector 3 (v3)	True	False
Vertex Color Buffer (vc)	Integer 32 (i)	True	False
Vertex UV Buffer (u%d)	Vector 2 (v2)	True	False
Vertex Weight Bone Buffer (wb)	Integer 32 (i), Short (h), Byte (b)	True	False
Vertex Weight Value Buffer (wv)	Float (f)	True	False
Face Buffer (f)	Integer 32 (i), Short (h), Byte (b)	True	True
UV Layer Count (ul)	Integer 32 (i), Short (h), Byte (b)	False	True if has uv layers else False
Maximum Weight Influence (mi)	Integer 32 (i), Short (h), Byte (b)	False	True if has weights else False
Material (Hash of CastNode:Material) (m)	Integer 64 (l)	False	False

Notes:

• Face Buffer is an index into the current meshes vertex data buffers where (0, 1, 2) are the first three vertices from this mesh.
• The Face Buffer follows CCW (right-handed) winding order, this may be different in other apis, where you may have to remap the indices.
• Each vertex descriptor buffer must contain the same number of elements ex: if you have 16 vertices, you must have 16 normals if they exist, 16 colors if the buffer exists. Otherwise it's assumed they are default / skipped.

Blend Shape:

Field	Type(s)	IsArray	Required
Children	None	True	False
Parent	Model	False	True

Property (id)	Type(s)	IsArray	Required
Base Shape (Hash of CastNode:Mesh) (b)	Integer 64 (l)	False	True
Target Shapes (Hashes of CastNode:Mesh) (t)	Integer 64 (l)	True	True
Target Weight Scales (ts)	Float (f)	True	False

Notes:

• At a minimum one Base Shape and one Target Shape must be present.
• Target Weight Scales indicates the maximum value the target shape can deform to. The count usually will match Target Shape(s) but if it does not plugins should fall back to 1.0 as the default.

Skeleton:

Field	Type(s)	IsArray	Required
Children	Bone	True	False
Parent	Model	False	True

Bone:

Field	Type(s)	IsArray	Required
Children	None	True	False
Parent	Skeleton	False	True

Property (id)	Type(s)	IsArray	Required
Name (n)	String (s)	False	True
Parent Index (p)	Integer 32 (i)	False	False
Segment Scale Compensate (ssc)	Byte (b) [True, False]	False	False
Local Position (lp)	Vector 3 (v3)	False	False
Local Rotation (lr)	Vector 4 (v4)	False	False
World Position (wp)	Vector 3 (v3)	False	False
World Rotation (wr)	Vector 4 (v4)	False	False
Scale (s)	Vector 3 (v3)	False	False

Material:

Field	Type(s)	IsArray	Required
Children	File	True	False
Parent	Model	False	True

Property (id)	Type(s)	IsArray	Required
Name (n)	String (s)	False	True
Type (t)	String (s)	False	True
Albedo File Hash (albedo)	Integer 64 (l)	False	True
Diffuse File Hash (diffuse)	Integer 64 (l)	False	True
Normal File Hash (normal)	Integer 64 (l)	False	True
Specular File Hash (specular)	Integer 64 (l)	False	True
Emissive File Hash (emissive)	Integer 64 (l)	False	True
Gloss File Hash (gloss)	Integer 64 (l)	False	True
Roughness File Hash (roughness)	Integer 64 (l)	False	True
Ambient Occlusion File Hash (ao)	Integer 64 (l)	False	True
Cavity File Hash (cavity)	Integer 64 (l)	False	True
Extra (x) File Hash (extra%d)	Integer 64 (l)	False	True

File:

Field	Type(s)	IsArray	Required
Children	None	True	False
Parent	CastNode	False	True

Property (id)	Type(s)	IsArray	Required
Path (p)	String (s)	False	True

Animation:

Field	Type(s)	IsArray	Required
Children	Skeleton, Curve, NotificiationTrack	True	True
Parent	Root	False	True

Property (id)	Type(s)	IsArray	Required
Framerate (fr)	Float (f)	False	True
Looping (lo)	Byte (b) [True, False]	False	False
Transform Space (ts)	String (s) [local, world]	False	False

Curve:

Field	Type(s)	IsArray	Required
Children	None	True	False
Parent	Animation	False	True

Property (id)	Type(s)	IsArray	Required
Node Name (nn)	String (s)	False	True
Key Property Name (kp)	String (s) [rq, rx, ry, rz, tx, ty, tz, sx, sy, sz, vb]	False	True
Key Frame Buffer (kb)	Byte (b), Short (h), Integer 32 (i), Float (f)	True	True
Key Value Buffer (kv)	Byte (b), Short (h), Integer 32 (i), Float (f), Vector 4 (v4)	True	True
Mode (m)	String (s) [additive, absolute, relative]	False	True
Additive Blend Weight (ab)	Float (f)	False	False

NotificationTrack:

Field	Type(s)	IsArray	Required
Children	None	True	False
Parent	Animation	False	True

Property (id)	Type(s)	IsArray	Required
Name (n)	String (s)	False	True
Key Frame Buffer (kb)	Byte (b), Short (h), Integer 32 (i), Float (f)	True	True

• Format designed by DTZxPorter with input from various developers.
• Icons by Smashicons