Project Files

This page describes all file formats used in a CaseTalk project. Each format has a specific role in storing, transforming, or presenting the information model.

Overview

Extension	Full name	Purpose
.ig	Information Grammar	The primary model file; stores all model elements
.igg	Information Grammar (Grouped)	A transformed view: grouped, reduced, and lexicalized
.igd	Information Grammar Diagram	A visual diagram based on an IG or IGG
.exp	Expression File	Natural language expressions for model elements
.ctprj	Project File	Lists the IG files and settings belonging to a project
.sty	Style File	Visual style settings for a diagram
.cadf	Application Definition File	UI configuration for custom attribute profiles and controls
.todo	Todo File	Modeling task list attached to a project or IG file
.ig.index	Search Index	Quick-search index of the type names in an IG file
.igt	IG Template	Reusable model snippet or template pattern

ig

The .ig file is the primary model file in CaseTalk. It stores the complete information grammar: all object types, fact types, label types, roles, expressions, constraints, population, and all other model elements.

Every IG file has a unique identifier called its namespace, which is used to track the origin of elements when models are merged.

IG files are listed in a project file and opened in the modeler. They can have one or more diagram files and an optional expression file associated with them.

File associations: Opening an .ig file launches CaseTalk directly into that model.

igg

The .igg file (Information Grammar — Grouped) is a transformed representation of an IG file. It applies three transformations to the model:

Grouped — fact types are organised by their primary object type
Reduced — redundant or derived facts are simplified
Lexicalized — expressions are resolved to produce readable natural language output

The IGG is generated from the IG and is used for verbalization, reporting, and publishing. It is not edited directly — it is always derived from the source IG.

igd

The .igd file is a diagram file associated with an IG or IGG file. It stores the visual layout and display settings for a subset of the model elements: which types and facts are shown, their positions, and any diagram-specific annotations.

A single IG can have multiple diagram files, each showing a different view or subject area of the model. The diagram designer supports several rendering modes including Fact View, Logical, UML, ERD, ArchiMate, and others.

Note: The diagram file stores layout only — the model content lives in the IG. Deleting a diagram file does not affect the model.

exp

The .exp file stores the natural language expressions for an IG file. It contains all fact expressions and object expressions across all locales defined for the model.

Expression files can be edited in the Expression Editor and are used for verbalization, documentation generation, and multi-lingual output.

ctprj

The .ctprj (previously .prj) file is the project file. It lists all IG files belonging to a project together with their relative paths, and stores project-level settings such as archive history and namespace references.

Opening a project file in CaseTalk loads all associated IG files and makes them available in the Project panel. The project is the top-level container for a modelling effort.

sty

The .sty file stores the visual style settings for a diagram. Style files control colours, fonts, shapes, line weights, and other visual properties. Multiple style files can be defined and switched between in the Diagram Designer.

CaseTalk ships with several built-in styles (Classic, Modern, Plain, ArchiMate, Hapsah, etc.). Custom styles can be created and saved as .sty files.

cadf

The .cadf file (CaseTalk Application Definition File) stores configuration for custom attribute profiles and UI control definitions. CADF files are used to extend the CaseTalk interface with domain-specific controls and metadata schemas.

todo

The .todo file stores the modeling task list associated with a project or IG file. It lives alongside the project or IG file and is managed through the Todo panel. Todo items can be linked to specific model elements via bookmarks.

ig.index

The .ig.index file is a lightweight text index generated alongside each IG file. It lists the type names defined in that IG and is used for fast search across all known projects without needing to open the model files.

CaseTalk uses .ig.index files to search across the full project history efficiently.

igt

The .igt file (IG Template) is a serialized model fragment used as a reusable snippet. It stores a complete model — including OFTypes, fact types, and expressions — that can be inserted into other models or applied as a pattern.

There are two kinds of .igt files:

Plain snippet — contains a set of OFTypes and fact types with no anchor. Inserting it opens a merge wizard.
Template snippet — contains an OTFT[template] whose name matches the filename. That OTFT is the anchor; fact types with roles played by the anchor define the reusable pattern. Template snippets are idempotent: applying one twice has no effect.

.igt files are stored in the snippets folder configured via Tools → Environment → Snippets. CaseTalk scans this folder at startup and makes all found snippets available in Insert → Snippets and (for template snippets) Apply Template on the right-click menu.

The three built-in named templates — Annotatable.igt, Transitional.igt, and Localization.igt — each activate a specific indicator on the target OFType and add a virtual folder to the Source Mapping panel.