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Basic Concepts of CAA V5

Approaches in Automation

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This article gives you Overview of Various approaches in CATIA V5 Automation

 

Advantages of Automation/Customization

  • Cost Reduction
    • Improved Efficiencies
    • Improved Quality Through Standardization
  • Customization
    • Provide additional functionality not provided in native products
    • Manipulate existing function to better fit customer processes

 

Examples of Automation

The application of automation in the design process is virtually unlimited. Some examples of automation at work:

  • batch script for the conversion of drawing files to PDF
  • export of points from Excel spreadsheet to CAD model
  • export of points from CAD model to Excel spreadsheet
  • grid of points, centered in CAD model (for element layout)
  • automatic spline creation (from selection of points)
  • create normal (perpendicular) lines to a surface

Automation tools

 

  • CATIA V5
    • CATScript,
    • VBScript
    • VBA
    • VB 6.0
    • CAA
  • Pro/Engineer
    • Mapkey
    • Pro/Program
    • Pro/Web.Link
    • J-Link
    • Pro/Toolkit
  • Autodesk Inventor
    • Autodesk Inventor API
  • Unigraphics NX
    • Knowledge Fusion (KF)
    • UFUNC

CATIA V5 Automation Tiers

CATIA (Computer Aided Three-dimensional Interactive Application)

  • Open architecture allowing to optimize solutions.
  • Process centric solutions

Native CATIA Automation

  1. Parameters – A feature defining a document or object property.
  2. Formula – A feature used to define or constrain a parameter
  3. Design Table – A table containing values to be applied to a document to manage parameter
  4. Templates – A Document used to store and reuse intent
  5. Power Copy – A set of features (geometric elements, relations,
    constraints) grouped in a generic context to be used in a specific context

Let us see them in Detail

1.Parameters

  • Intrinsic Parameters -
    • Created  by CATIA as a byproduct of geometry creation
    • Cannot be deleted without deleting associated geometry
  • User Defined – Parameters created by the user for a specific purpose
    •  Magnitude (Real, Length, Speed)
    • String
    • Boolean
    • Geometric (Point, Circle, Plane)
    • Import From Spread Sheet

    •  

2. Formula

  • Formulae – Relations specifying a constraint on a parameter.
  • Formula Wizard – A tool provided to assist with the syntax and format while applying a formula to a parameter.

3. Design Tables
 Design Table

  • Provides a means to create and manage component families.
  • These components can be for example mechanical parts differing in their parameter values.
  • An associative link is created between spread sheet and Part or Product

Design Tables can be created in following formats

  • Excel Spread Sheet
  • Tab Delimited Text Files
  • CATIA Design Table

4.Templates

  • A document (Part, Product, Drawing, Process) created in a general context for reuse
    in a specific context.
  • The new context is defined be modifying parameters or replacing specification geometry.
     

5.PowerCopy

  • A Power Copy is a set of features (geometric elements, formulas, constraints and so forth) that are grouped to be used in a different context, and presenting the ability to be completely redefined when pasted.
  • A Graphical interface is provide to guide user through selection of inputs and valuation of parameters.
  • Can be instantiated from a Document or from a feature catalog.


CATIA Knowledgeware

  • The CATIA V5 Knowledgeware turns implicit design methods into explicit knowledge for obtaining the optimum design.
  • Quick assessment of the best alternative for a design amongst numerous combinations of parameters and constraints.

Disadvantages

  • Complex Models Difficult to Maintain
  • Lacks Debugging Help
  • Requires Additional Licenses
     

Knowledgeware Applications

  1. Knowledge Advisor
  2. Knowledge Expert
  3. Product Engineering Optimizer

1.Knowledge Advisor

KNOWLEDGE ADVISOR is a CATIA product which allows users to embed knowledge within design and leverage it to assist in engineering decisions, in order to reduce errors or automate design, for maximum productivity
Knowledge can be embedded in design in form of

  1. Parameters (Already Covered in Native CATIA Automation)
  2. Formulae (Already Covered in Native CATIA Automation)
  3. Rules
  4. Checks

The rule and check capabilities require the Knowledge Advisor product.
 

A RULE  is a set of conditional statements, whereby the relationship between parameters is controlled.
A Check is a set of instructions used to analyze the value of specific parameters. It causes no events. It simply provides feedback to users in following ways

  • Silent : No message is displayed
  • Information: A user defined message is displayed

 

2.Knowledge Expert


The Knowledge Expert product allows you to create and manipulate relation-type features. These particular features are organized into a hierarchy.

  •  Expert Rule: An expert rule is a set of instructions whereby you can start an action for any object having a type defined in a type list.
  • Expert Check: An expert check is a relation which only verifies that a condition is true for all the objects of one or more given types. It does not modify the document it is applied to.

3.Product Engineering Optimizer

 

  • The Product Engineering Optimizer is tool to optimize product and part designs by minimizing, maximizing or targeting specific parameter values.

Problem Tab

 

Constraints Tab

Computation Results Tab
 


 

VB/VBA

  •  Macros / .CATScripts
    • Free, Rapid Deployment, Easy to Reuse Recorded macros, Limited Flexibility, Difficult to Debug
    • Great tools for rapid deployment of simple automation applications
    • Personal time saving operations
    • They are limited in scope and flexibility.
  •  VBA / .CATvba
    • Free, Graphical User interface (Forms), Editor Provides Debugging Capability
    • Offer increased flexibility and complexity through implementation of user interface forms and modules
    • Requires a short learning curve
    • VBA Environment is Not Object Oriented
  • VB6 & VB.NET– Runs Outside of CATIA, Increased Implementation of Components and Type Libraries, Individual Module Files Makes Collaboration and Sharing Code Easier.

How VB Automation works?
 

  • How does it work?
    • Dassault Systemes has “exposed” several CATIA objects so that they can be created, manipulated, and deleted by COM compliant applications
  • How does VB talk to CATIA?
    • dll’s – Dynamic Linked Libraries
      • These are compiled files that contain all of the functions that make CATIA V5 perform an action.
      • These files are both compiled and encrypted
      • These files are located in the UNLOAD directory for CATIA V5 (normally “c:\program files\Dassault Systemes\B20\intel_a\code\bin”)
    • tlb’s – Type Library Files
      • These files are necessary for “exposing” functions to Windows.
      • They act as maps which point to the mangled functions inside of the dll files that make CATIA V5 work.
      • The tlb files are located in the UNLOAD directory for V5.
      • Any external application needs to have access to (and reference) these type
        libraries

 

CAA

CAA (Component Application Architecture)

  • More Powerful and Faster than VB, Harder to Learn, Provides Access to Interfaces not currently available to Visual Basic.
  • The Primary language for development is C++. Java is also supported but it not as common.

Advantages of CAA

  • Single source code for both WINDOWS and UNIX
  • New wizards like workbenches, interactive commands, dialog boxes etc., can be created
  • Add new data and behaviors on an existing feature without overloading standard behaviors
  • No specific Run time license is required
  • Customized GUI using
  •  

Conclusion

Reading a part body through CAA V5 API

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Different ways to read a catia part

  1. Topology based reading
  2. Feature based reading

1.Topology based reading

1.1What is topology?

 

  • Topology is a logical information describing the boundary of geometric objects.
  • Topology allows to represent objects, by detailing their boundaries and the connections between their different parts

1.2 Basic topological objects in CGM

The topology manages three types of entities
 

1.2.1 Cell

A cell is a connected limitation of underlying geometry. There are 4 types of cells according to the dimension in the space in which they lie
 

  • Vertex
  • Edge
  • Face
  • Volume

Different types of cells and its associated geometry are shown below

1.2.2 Domain
  • A domain is a set of connected cells grouped to define boundaries.
  • A domain is a set of cells of dimension [n] connected by cells of dimension [n-1].
  • Domains define manifold components inside a non-manifold objects

 

1.2.3 Body
  • A body is a set of domains not necessarily connected.
Slide 6
Different types of cells and its associated geometry

Structure of CAA V5 Containers

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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

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