Friday, 14 September 2012

All about CATIA - part 2

CATIA basics
Does CATIA work on Windows Vista or Windows 7?

In my experience, R18 of CATIA 5 aborts during installation on a Vista 32bit operating system.  It will install and run on a Vista 64 bit operating system and Windows 7 operating system.  However, the licensing server won’t run on Windows 7 yet.  Dassault will probably sort out this problem with a release in 2010 or early 2011. CATIA v6 installs and runs on Windows 7. And yes, Catia V5 can run on a Unix platform.

 System Requirements

Here are some basic system requirements that you should follow to make sure you can install and run CATIA v5.

• Your workstation needs to be at minimum an Intel Pentium III or Pentium 4 based.

• Memory: 256 MB of RAM is the minimum recommended for all applications. 512 MB of

RAM is recommended for DMU applications. These days a Windows workstation will come with a lot more RAM, which is very helpful.  The more the better, at least 2GB to run well.

• Disk drive: 4 GB is needed for the install. You will want a lot more free space on your C drive; at least 25% of the disc free so you can run the program well.

• You’ll need a DVD Rom for installation of course.

• Display: A graphic color display compatible with the selected platform-specific graphic

adapter. The minimum recommended monitor size is 17 inches.

• Graphics adapter: A graphics adapter with a 3D OpenGL accelerator is required with

minimum resolution of 1024x768 for Microsoft Windows workstations and 1280x1024 for

UNIX workstations.

 How is CATIA organized?

CATIA V5 is organized into what are called workbenches.  A workbench is a working environment with a specific set of tools appropriate to the dominant task of that workbench. 

 CATIA has a number of basic workbenches—

  1. the sketcher workbench,
  2. the part design workbench,
  3. the wireframe and surface design workbench,
  4. the assembly design workbench, and
  5. the drafting workbench.

 Think of each workbench as a place where you perform a certain task, like drawing, or solid modeling, putting your parts together so they work as a whole (that’s what the assembly environment is about), etc.  Let’s take a moment to define what each workbench does:


·         The Sketcher Workbench is where you do your drawings.

·         The Part Design Workbench is the parametric, feature-based environment where you create solid models.

·         The Wireframe and Surface Design Workbench, like the part design workbench, is also parametric and feature-based, but in this workbench you create wire frame models or surface models, as opposed to solid body models.  A surface is like the “skin” of a solid, but it has a zero thickness value.  The tools in this workbench are similar to those of the part design workbench, but you have additional functionality for creating and manipulating surfaces. 

·         The Assembly Design Workbench is where you assemble the components you’ve modeled, constraining them so they work together properly and accurately. There’s two methods for creating assemblies, top-down and bottom up. 

·         The Drafting Workbench is where you document your work, for example, by creating detailed drawing views that you’ll be sharing with your customer or suppliers/vendors. When we talk about drafting later on, we’ll be learning about the two methods of drafting, interactive and generative.

 
CATIA file extensions

·         CATPart – this is the file extension for the files you create in the Sketcher, Part Design, and Wireframe and Surface Design workbenches. 

·         CATProduct – this is the file extension for a CATIA assembly. 

·         CATDrawing – this is the file extension for the files you make in the Drafting Workbench.

 
Some important terms you should understand before we start…
Feature-based Modeling

In 3d CAD design, you start with a sketch, and then turn it into something 3D, either a solid or a surface—these are features.  A feature is defined as the smallest building block that can be modified individually. Then you put your features together into parts, and your parts together into assemblies.  A model created in CATIA V5 is a combination of a number of individual features andeach feature is related to the other directly or indirectly.

 
Parametric Modeling

This is a term that’s really easy to understand, actually, but seems confusing at first. Basically, you create your 3D models using sketches that have parameters like size (length, width, area etc) and relationships (parallel lines, equal sides etc).  The relationships are called constraints in CATIA.  These parameters can be changed anytime during the design, modeling and documenting process fairly easily, so that you don’t have to start from the beginning if you want to make a small change. This is the single most cool and time-saving functionality of computer aided design, as distinguished from paper-based design, where you’d have to rebuild the whole thing from scratch if you wanted to see how a small change works.

 
Bidirectional Associativity

This basically means that your work updates across all CATIA environments; if you make a change in one workbench, you won’t have to duplicate it elsewhere; CATIA does that for you.  The bidirectional associativity ensures that if any modification is made in the model in any

one of the workbenches of CATIA V5, it is automatically reflected in the other workbenches

immediately.

Specification Tree

The specification tree appears on the left of your screen, and keeps track of all your operations, in a nested format that lets you see how you made a feature. Each sketch and feature, etc, has its own branch or node in the tree, and if you expand a branch, you can see of what that branch is comprised.  The specification tree that appears when you start a new file under the Part Design workbench.

 

Compass

The CATIA compass is a tool that is used to manipulate the orientation of parts, assemblies, or sketches.  You can also orient the view of the parts and assemblies.  By default, it appears on the top right corner of the geometry area.  All the 3D CAD programs have something like this; in AutoCAD it’s called the UCS, or User Coordinate System; in Inventor, you have the View Cube also.

 
Constraints

Constraints refer to the relationships among your geometric entities, or drawing elements. In the sketcher workbench, you use geometric constraints to define the size and position of your drawings, and then you apply numerical dimensions to precisely define the size.

 Constraints also refer to the relationships among your parts; these are called assembly constraints and they are available from the assembly design workbench.

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