Digital Mock Up

Digital Mock-Up Methods Lecture 5 Warren Hall

The role of 3D Mock-Up • Digital Mock-Up is latest innovation in digital product development – allows full visualization of complete product in 3 dimensions – Permits collaborative engineering as all users can see other users work as it evolves – improves error detection by locating clashes / interference's earlier in process

Evolution of the mock-up • Mock-up development began with introduction of 3D modeling • First mock-ups were created using one huge model with all parts included – Very poor performance due to model size • With development of multi-model sessions one session was used to position several models – had to copy session for more than one user – data integrity issues • now implemented using relational databases

Digital Mock-Up • A digital mock-up is – a collection of 3D models which are positioned in 3D space to represent the form of the product to be developed

Digital Mock-Up • All geometry is accessed via the database – models may be in database or pointed to by the database

• Each model is attached to a part in the product structure (BOM)

Mock-Up Schema Digital Mock-Up

Mock-Up Database

Bill of Material (Assembly Structure & positioning)

Geometry

Role of The Master Model • Not all representation types are used in the digital mock-up • The 3D master model is the model which is used to build the 3D mock-up – represents prime 3D definition of part – at Bombardier this is the structural model – at PWC this is the PDS model

Derivative Representation Types • Positioning applies to all models attached to a part • although mock-up is almost always constructed using master model one can build a mock-up from other rep types for specific purposes – FEM rep types for simulation contact analysis

Basic Mock-up Methodology • Basic steps to creating a mock-up – – – –

1. Create the parts 2. Create the Bill of Material structure 3. Attach the models to the parts 4. Position the models to create the mock-up

• Parts must be created within their context and at their final position – the latest surrounding geometry must be easily retrievable

One Part per Model • Key methodology in implementing BOM driven mock-up • In order to observe the structure of the BOM, a geometrical (CATIA) model should contain the definition for only one part – For initial designs of parts, they may be included in layout models. They can later be exploded to detail parts within the BOM structure

• Better structure and simplified management of information • enables part re-usability

One Part per Model Methodology • A part is a collection of specific attributes • CATIA models also have attributes – name, representation type, etc.

• A model must be attached to a part • A part does not necessarily have a model attached to it

Exceptions - System Software • In certain cases there are exceptions to one part per model methodology • Decision to make exception must be carefully weighed – Gains vs. Losses

• Within CATIA environment systems Software (Electrical Wire Bundle, Tubing) is one such exception

Exceptions • To maintain intelligence of systems software all elements (I.E. wiring harnesses and supports) must be in the same model – this automates re-routing with automatic support placement

• If one part per model methodology implemented intelligence would be lost – Results in net loss of productivity

Exceptions • Methodology to document exception must be developed – One possible solution is to store wiring harness model data at assembly level – Parts at sub-assembly level that should hold connectors, etc. have no models attached

Exceptions • Graphically following OPPM methodology Harness Assembly

Harness Part

Support Part

CATIA CATIA Model Model

Support Part

Support Part

CATIA Model

CATIA Model

Support Part

CATIA Model

Exceptions • Graphically, alternative methodology

Harness Assembly

Harness Part

Support Part

NOTE: No models attached at part level

Support Part

CATIA model containing harness & supports

Support Part

Support Part

Associating a Model to a Part • To insert geometry in the database the model must be attached to a part • General methodology – Using the VPM part object create the part in the proper environment (CAMAQENV) – Start CATIA and make the desired model active – select the model object in VPM

Associating a Model to a Part • General methodology - cont. – Click on the SAVE icon – complete the required fields in the panel – select ok to save

• NOTE – the part can be created at the same time the model is being saved

Associating a Model to a Part

Associating Non-Geometric Data • Non-geometric data is associated to observe the concept of the part (specs, etc.) • No relevance in digital mock-up context yet key to using BOM as data management tool • VPM refers to non-geometric data as DOCUMENTS • each document has an associated viewer used to view/edit (I.E. MS WORD)

Associating Non-Geometric Data • As with models data may be stored physically in the database or pointed to by the database yet must be accessed via the DB • Some “typical” documents – FEM post processing results – specs – performance data

Associating Non-Geometric Data