Asset Plug-In API

Classes
class	Foundry::Katana::DefaultAssetPlugin
	Allows the access to the currently set Asset Management System plugin. More...
class	Foundry::Katana::DefaultFileSequencePlugin
	Allows the access to the currently set File Sequence plugin. More...
class	Foundry::Katana::Asset
	Primary class to derive from when implementing asset system plugin. More...
class	Foundry::Katana::AssetTransaction
	Virtual base for asset transactions. More...
class	Foundry::Katana::SimpleAction
	Simple action base class for performing an action (doit) and rolling it back (rollback) in case of error in this or subsequent action. More...
class	Foundry::Katana::SimpleTransaction
	Simple transaction maintains a list of actions. If an action returns failure during commit, execution is canceled and rollback() is called on all previously executed actions in transaction. More...
class	Foundry::Katana::FileSequence
	Primary class to derive from when implementing file sequence plugin. More...
class	Foundry::Katana::FileSequenceArray
	Container class that holds a vector of FileSequence instances and a vector of non-sequence filenames. More...

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Detailed Description

This API allows the implementation of two plugin types:

• Asset Plugin - which implements the connection of Katana with an Asset Management System (see Asset).

• File Sequence Plugin - which tells Katana how a fileSequence should be described as a string, and how to resolve that string into a real file path when given a frame number (see FileSequence).

Each Katana Scene will have one Asset plugin and one FileSequence plugin associated with it (see in the Katana UI: Project Settings tab-> plugins -> asset / fileSequence) Which can be accessed from other plugins using the classes DefaultAssetPlugin and DefaultFileSequencePlugin

Both Plugins can also be implemented in Python with a very similar interface (see the documentation for the AssetAPI Python module). Python plugins will be accessed by Katana and by any plugin using the DefaultAssetPlugin and DefaultFileSequencePlugin classes in a transparent way.

General design

An asset, as used in Katana, is a reference to input/output data -- usually files on disk. The reference typically resolves to a file path or sequence on disk, but this is not a requirement. It could resolve to a colorspace name or shader library version string, for instance. Scene files, input geometry/images, look files, and more can be referenced as assets in Katana. Although all these inputs and outputs can be specified directly as file system paths, asset systems exist to provide higher-level tracking, versioning, and publishing of this data than the file system alone provides.

Assumptions about asset systems

• A reference to an asset can be uniquely serialized to/from a single string value (referred to as an AssetId). In Imageworks' Vnp system, this is the spref url syntax(e.g. {spref:product.type?v=current}), but could just as easily be a guid or a serialized python dict.
• Each asset has at least two levels of hierarchy: the basic asset container, which may contain multiple asset versions.
• Each asset reference has some basic required Fields associated with it ("name" and "version" are currently the only two mandatory fields for every asset).
• Each asset can have a set of non-mandatory Attributes (name/value pairs) in which some meta-data related with the asset can be stored or used by the Asset Management System (Example: an image asset might have its LUT name, file type and resolution associated with it)

File Sequence Plugins

File sequence Plugins allow to set the way file sequence paths are represented and resolved by Katana. Check the documentation about the FileSequence class for more information.