Technical Article

Parametric Modeling in CATIA CAD Software for Process Optimization

February 02, 2020 by Maher Elkhaldi

Learn about CATIA, a CAD software program used for parametric modeling, and how it can improve automated processes.

Automation is a process of embedding decision making into inanimate objects. Here, objects can be physical (hardware) or virtual (software). For example:

  • Robotic fabrication and assembly lines for building computer chips executed by hardware, and defined by software
  • Programs to execute deterministic and non-deterministic tasks for form synthesis and optimization

Both types of automation are enabled by software.

Every software has a core engine with functions dedicated to executing tasks. Most software tools nowadays expose some of their internal functions to be triggered and controlled externally. These are known as Application Programming Interfaces (APIs).

This post will focus on CATIA, a parametric modeling CAD system famous for its robust solid modeling kernel and assembly-based data model.

 

CATIA logo

 

CATIA in Automation: Levels of Support

CATIA offers a few levels to support automation. The first focuses on scripting, the process for writing code to execute tasks.

 

Knowledge-Based Engineering

When writing a script, users (developers) cannot create their own abstract concepts. They are limited to using the system's existing concepts. For example, it is not possible to create a rounded-corner polygon object. Users will need to construct that as a series of line segments and arcs.

That said, CATIA supports creating custom features and assemblies that can be augmented with such scripts. This enables building self-configuring objects, which is the cornerstone for Knowledge-Based-Engineering (KBE) workflows. The language CATIA provides for this level of automation is the Enterprise Knowledge Language (EKL). I'll refer to this level as KBE.

 

Engineering Support

CATIA also exposes a large set of APIs to dotnet languages (C-Sharp and VBA) as well as C. These languages can be used to create new abstractions (object types composed from system-defined objects).

At this level, users can tap into system services and connect with other APIs. For example, you can export and import the coordinates of a point grid to and from a CSV/Excel file. I'll refer to this level as Engineering Support (ES).

 

Optimization

Another area of automation is optimization. At this time, CATIA supports only single-objective optimization. Users define sets of free variables that can be controlled by the optimization algorithm (selected from a set of predefined ones). They can also impose constraints and ranges to guide the optimization tool through the solving process to filter and narrow the solution space. I'll refer to this level as optimization.

 

How CATIA Can Optimize Automated Processes

The above three levels (KBE, ES, and optimization) can be used to orchestrate robotic arms simulations for fabrication pipelines.

For example, let's say an engineer must design motion paths for x number of robots to carry metal panels from a carousel, lay them down on a welding jig, perform welds, and then transport them back to another carousel. This process can benefit from automation to analyze and optimize execution times. Shaving a second off an assembly station could have significant cost savings (a major driver in automation) especially when producing at scale.

 

A rendering of a hydraulic arm in the CATIA interface. Image used courtesy of Dassault Systemes 3DS Academy.

 

Automation must also consider quality and standards. It is possible to augment the process of creating and storing CATIA objects (i.e., data) with a set of business rules to ensure certain standards are met.

For example, engineers can control naming conventions, validate parameters and descriptions to ensure they are filled and valuated correctly, flag issues with model organization, etc. all within CATIA.

 

Asynchronous vs. Synchronous Execution

An important aspect to highlight when automating parametric modeling systems is asynchronous (concurrent) vs. synchronous (sequential) tasks.

CATIA, much like other parametric CAD tools, builds relationships between elements top-down to ensure data integrity and prevent cycles. For example, data flows from A to B. Never will it flow back from B to A. This nature is protected by restricting most of the execution tasks to being synchronous: proceed to the next step once the current one is completed. This ensures that data is never accessed by more than one process at any given moment.

I think of automation in parametric modeling systems as a subset of programming. One that is disciplined by synchronous execution and empowered intelligent objects. 

 


 

Do you have experience with CATIA? Have you used parametric modeling to optimize a system before? Share your experiences in the comments below.