A Separate Forum for CATIA V5 KBE Community

This is to inform you that COE has launched a new and separate Forum for Knowledge-based Engineering) KBE. This is a separate discussion track devoted to KBE, KBE tools, KBE Techniques, KBE tips, KBE Methods/processes, KBE Templates, COE/KBE DPC questions and COE/KBE track Presentations.

Purpose: One of the purposes of setting this forum is to provide our CATIA V5 KBE users-- a neutral platform to discuss & ask questions, submit modeling tips, KBE hints, and suggest KBE-enabled solutions.

In KBE, often we are trying to capture the "INTENT" or the "DEFINITION" of the part/model. Meaning, "What you would like to do with the model eventually? Why are you making your model KBE-enabled? What possible variations you like to see in the model? What to morph this model into? And Why? What Techniques to use?

Not knowing "which KBE techniques are better than others" and "what KBE technique makes a model generic (morphable)" make our KBE developers' life difficult -- when using various KBE tools.

If anyone of you have direct interests in using any KBE, or any KBE (CATIA V5 KnowledgeWare) tools (like KWA, KWE, PKT, PEO and BKT workbenches), or if you have KBE questions, please do not hesitate to post your questions on this KBE forum.

Thanks for your support and participation,

Introduction to the CATIA V5 Knowledge Template
Franck Montigon, Strategy, CATIA V5 Shape Design & Styling, Knowledge and Analysis Solutions

Introduction

One of the main purposes of the CATIA V5 Knowledgeware solutions is to capture the trade know-how required for product design and harness this knowledge to develop new, better quality and faster products, notably by the creation of intelligent templates. These Knowledge Templates, as they are known in CATIA V5, combine varied elements included in product design. The templates are then reused either by the same team/project/company, or through the extended enterprise by way of exchanges between Original Equipment Manufacturers (OEM) and suppliers for example. This components-based approach accelerates and simplifies design.

Definition of a Knowledge Template

A Knowledge Template is comprised of varied elements such as geometry, product structure, and especially trade know-how as defined in CATIA V5 Knowledgeware. The most common knowledge elements are: Formulas and Rules(to parameterize a component), Design Tables(to define component alternatives), Checks(to check that the components match rules relevant to the company practices). There are also more advanced functions such as Optimizations(to optimize a component), Reactions(which can add a behavior to a component) and Sets of Equations(to solve equations and inequations).

It is this wealth of knowledge that enables both the creation of intelligent components, which are able to adapt to a new context (component morphing), and the efficient communication of the original design intent.

To fully appreciate the power and benefits the Knowledge Templates offer, it is worth noting that the Knowledgeware is one of the core components of CATIA V5, launched in 1999. The result? Knowledge can be accessed and used at every product design stage, from the concept to the maintenance, as well as be enriched interactively from all V5 applications.

The Knowledge Template can be classified in three categories, depending on whether the original design is:

• A sub-part element, in which case it will concern Feature Templates.
• A whole part, in which case it will concern Part Templates.
• An assembly (several parts and/or sub-assemblies), in which case it will concern Assembly Templates.

There are two types of Feature Template:

• The first allows for quick reuse of the design while controlling all the reused elements, i.e. being able to modify everything. These are PowerCopy templates (PwC).
• The second is just as fast but its exterior view is a “black box” (users cannot modify elements apart from some control parameters). These are User-Defined Feature templates (UDF).

Either type of feature template may be chosen depending on the degree of control sought and degree of confidentiality required (Intellectual Property protection).

The creation and reuse of the two types of feature templates is very similar. Part Template and Assembly Template creation follows exactly the same pattern.

Your geometry is created as well as all the knowledge elements that comprise it. The figure 1 shows the screen that enables interactive creation of a Feature Template. There are a number of tabs that we shall look at in their order of use:

1. You need to select the component to transform into a template in the Feature Tree. The "Definition" window will then display the list of components to choose from, the related external documents and the inputs required for the instantiation of the template, i.e. the input elements that the end user will have to indicate to insert his component in a new context.
2. Then rename these entries to make them as easy to understand as possible using the "Inputs" tab.
3. "Parameters", the third tab, enables the creator of the template to choose the parameters accessible after instantiation (in case of a UDF).
4. Customize your template by attributing a particular icon to it for a quick identification in the Feature Tree ("Icon" tab).
5. Indicate the geometric output elements that you want to use to support future developments (UDFs only)
6. Attribute a specific identity to your template, recognized by the V5 infrastructure, for advanced operations (search, rules, etc). (UDFs only)
7. Click OK. Your template has been created and may now be found in the Feature Tree of your part.

Add extra knowledge

Note that for even easier use of your template, you can add extra documents to explain how you created your component and how it should be reused in much more detail. This information will be accessible directly by the end user, through URL links, when he wants to instantiate this template.

Store, Share, Deploy

After reusing your Feature Template, you can opt for different means of saving:

• The "file based" mode enables you to store your Feature Template like any other file and reuse it with the "Insert component" command.
• The CATIA catalogues permit you to consult categorized information, provide wider distribution and simplified reuse thanks to previews of templates.
• Lastly, you can also save your templates in V5 Product Data Management systems (ENOVIAVPM, ENOVIA V5 LCA), and in SMARTEAM.

Reuse your Feature Template in another context

1. From any CATIA workbench, go to the menu and select "Insert from catalog", choose the template to instantiate, the window figure 3 will appear. This panel is comprised of a list of entries to fill in, an interactive window to view the component to be inserted, an explanation of the entries, and an access to more detailed information.
2. Select the inputs either directly on your model, or in the Feature Tree, or click on "Use Identical Name" if your entry parameters have already been identified in the context where you want to insert your template (automatic reconnection).
3. Click on OK. Your Feature Template has been instantiated and is adapted to the context.

After-reuse modifications

If you have chosen to create a Power Copy you can modify everything, since you have retrieved the original structure and information. However, if you have opted for a component-based approach (black box) via a UDF you can only change the entries and the parameters left free by the template designer.

Example of an Assembly Template

Here is a simple example of an Assembly Template. It is a trailer coupling, an assembly comprised of three parts.

1 – Instantiation of the Assembly Template (automatic reconnection),

2 – The template adapts to the context (shape, size, stiffeners, holes).

3 – The assembly to which the coupling is fixed is modified through the "Replace Component" command. The template adapts automatically to this new shape.

Summary

To recap, here are the points that we have dealt with in this article:

• Firstly, the user-friendliness of Knowledge Templates makes it a simple and powerful tool for capturing and reusing know-how. Everything is done interactively, whatever application you are working on.
• The knowledge integrated into these Templates allows it to be adapted instantly while spreading the company's best practices.
• Finally, the components-based approach speeds product design and increases productivity.

New Directions for CAD #2
Kurt Swanson, Boeing

This is a second article that looks at the dichotomy between natural and complex forms and manmade objects. This dichotomy in part is caused by limitations in CAD.

The evidence of minimal structures in nature can be examined in the formation of microporous structures present in marine skeletal structures. Three dimensionally microporous skeletons are found in echinoderms and certain species of coral. The side of the pores ranges from 15 to 500 micrometers (um) depending on the species.

Replamineform (meaning replicated life-form) materials have many applications; to date, they have been evaluated as medical devices and prostheses. The size of the microporosity makes the process ideal for making artificial organs and implants that become ingrown with host tissues. Microporous biomaterials can be used to replace bone, blood vessels, trachea, and other damaged tissue and organs.

Rather than to implant these biomaterials, Computer Aided Tissue Engineering (CATE) seeks to model these complex forms in precisely the right form (and with living tissue). Initial attempts to create scaffolding include tetrahedral and cubic lattice structures with cylindrical rods forming the edges of the unit lattice. The feature sizes for scaffolding are about 20 to 40 um. At this feature size the practical limit of the model is about a cubic centimeter -- this is a current computational boundary of a logically equivalent model.

Ten years ago the practical limit of a CATIA Boolean operational limit would be 100 cylindrical extractions from a cubic plate. The standard CAD practice is to require logical equivalence between the CAD model and the physical part. It is increasingly evident that such logical equivalence is impossible to maintain with the growth in definition and refinement of engineered structures. In composite modeling, for example, the database is required to maintain all of the flat pattern shapes and fiber orientation, stacking sequence, and the perimeter curves of each ply as it is applied to the lay-up mandrel. Not only does the database serve to define the part but defines the cutter paths and laser boundaries of the individual plys. The size of the database for simple composite parts is enormous.

For freeform biologics, the feature size differentiation precludes a logical equivalence. The differentiation of features is far too complex. We can know that the creation of biologics is the result of simple rules that are repeated over and over on a microscopic scale resulting in extraordinarily complex features. The most simple organs have a feature density, that when scaled, is beyond our most complex engineered part. Microcircuits which have high feature density but substantial uniformity).

Similarly, a practical CATE design approach is take a uniform Euclidian lattice and to replicate this basic structure in different scales and orientations to provide differentiation of structure in bone according to Wolf's law (Wolf's Law states that "bones respond to stress by making more bones". ). In practice the replication of a simple geometric pattern is insufficient to mimic the complex structures of spongy bone as the boundaries are difficult to manage. The underlying biologic process is fundamentally different than the Euclidean precepts that we impose.

In biologics: there is a set of initial boundaries; an automata or set of instructions on the interrelation of the parts; and there is an environment within which constrains and modifies the development of the organ. Biologics therefore lack a logical equivalence between codification and physical form, instead they have a computational equivalence that includes an automata, a sparse initial form, and an environmental response.

About the author: Kurt Swanson is a Senior Engineer (Boeing, Philadelphia, kurt.w.swanson@boeing.com). His interest is to expand the set of CAD surfacing tools currently utilized for design and to provide affordable, quality aerospace products.

The Past Year

Knowledge technologies continue to be an item of interest. There is a new Category in the COE Forums dealing with KBE.

Forum – Knowledge Based Engineering

The entries in the following table are articles from the recent past collected together for easy reference. We’re looking for articles about a variety of subjects, such as Knowledgeware, modeling techniques, etc.

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