Structure of CAA V5 Containers

Basically all CATIA V5 document are following the same structure like header, blocks, containers, link to the container and footer. The CATIA document (file) may be either of the following type, the type includes CATPart, CATProduct, CATProcess, CATAnalysis and CATProduct. This article explains the content of any CATIAV5 File/Document containers and its relationships in CAA framework. ObjectModelerBase is the common framework for all the CAT Documents

The Containers of a CAT Document

All CATIA V5 document contains large number of blocks some of the blocks are referred as containers which holds the data like geometry, feature, sketch, annotation etc., and the containers are as follows

1. Product container (CATProdCont)


This container contains an ASMProduct feature. This feature serves as reference for all the instantiations of the CATIA document in Product documents (Assembly). The instantiation may be the instance CATPart or CATProduct itself. This CATProduct is called sub CATProduct (Sub Assembly). This container stores list of specification object, the first object is called root assembly, It has the product properties or part properties incase the CATDocument is CATPart. CATIProduct, CATIPrdProperties, and CATIMovable are the principal interfaces

 

2. Document property

This holds the information of the instance in an assembly. The information includes the transformation matrix, translation vector, assembly name and path of the CATDocument. CATILinkable object is the interface which has link with the instances of the product

 

3. The Part/specification/Root/Feature container (CATPrtCont)

It contains the design of the mechanical object. This design is defined by mechanical features which can be seen in the specification tree

There are three kinds of mechanical features:

  • Part: the main feature containing the design of the object
  • Geometrical features sets: the features containing either geometrical features sets or geometrical features
  • Geometrical features: holds a topological result

CATInit, CATIContainerOfDocumant, CATIPrtContainer, and CATIPrtPart are the few of the basic interfaces

 

Fig-1 Specification Tree

Part, geometrical features sets and geometrical features are again spec object as in the product container

 

4. The Scope Container

During the design, it can be useful to select an edge, or a face, for example, to create a form. These topological objects will be the inputs of a mechanical feature. But a feature cannot reference directly a topology as specification. The main reason is that geometry and topology can be deleted during an update. Consequently topological objects are unstable. The solution implemented in V5 to overcome this problem is to use a name instead of a direct reference to the topology. Such a name is called a generic name. It provides a stable way to reference a topological cell or topological sub element. CATIMfBRep and CATIMfBRepFactory are the principal interfaces

 

5. The CGM (CATIA Geometrical Modeler)/Result Container

The Geometrical is the container which contains the topological results of the geometrical features. A geometrical feature is a mechanical feature for which a topological object can be associated with its result. This topological object is a CATBody. The body can be in the form of solid, surface and wire. CATICGMCntainer, CATICGMObject, CATGeometry and its type are some of the major interfaces/class.

 

6. The TPS (Topological Product Specification) Container

These are specification object as in CATPrtCont or CATProdCont, This container has been first dedicated to functional dimensioning and tolerancing but is to be extended to handle roughness, hardness, and furthermore user specifications. It describes the general type of feature among Datum, Dimension, Form, Position, Orientation and RunOut. CATITPSDocument CATITPSSet, CATITPSView and CATITPSViewFactory are the some of the basic TPS interfaces

7. The TTRS (Technologically and Topologically Related Surfaces) Container

This container has list of surface geometry features upon which the product specification is applied. Component provided by the MechModInterfaces framework used to link TPS with surfaces. CATITPSTTRSServices, CATITTRSGeometry, and CATITTRS are the some of the basic TTRS interfaces

 

8. The Draw Container

A drawing document is a collection of sheets, A sheet aggregates views and a view aggregates all objects instantiated in it. Drawing, sheet and views are specification object. It’s structure is same as part container, same interfaces like CATIContainer and CATIContainerOfDocument are used to retrieve this container

 

9. The Standard Container

Standard container provides the drafting standards like ISO, ANSI, ASME and JIS and drawing sheet format like A ANSI, B ANSI etc., and the default standard is ANSI

10. The SeeBody Container and Camera Startup Container

See body container stores the identifier of the geometrical entity which is visible in the document and Camera Startup container stores the latest image of the CATIAV5 document

 

11. The CGR (CATIA Graphical representation) Container

It has the tessellation data. The tessellated geometrical data are stored in the form of points, lines triangles, strips and fans. This again follows the structure of CATDocument like header, containers and footer

 

Link Between the containers

All the mechanical features are included in the specification container. Among the mechanical features, one can find the geometrical features. A geometrical feature has the particularity of having a result which holds a topological result. The topological result, a CATBody, is included in the geometrical container. The scope which guaranties the naming stability of the sub-elements of the CATBody is contained in the scope container.

Mechanical features essentially capture the design intent of the end user. When it comes to computing the shapes that correspond to this intent, they rely on an underlying modeler, the topological objects

Fig-2 CATDocument Structure