Translation Technologies - CAD File Translations

CAD Interoperability

Interoperability involves more than just converting the geometry. CAD interoperability, or interoperability between CAD systems is realized when the converted model file is fully functional in the target CAD system. Full functionality involves more than just the ability to move a hole, or redefine a protruding boss. The details of how the geometry is defined must be available to the CAD application so that they can be fully analyzed and manipulated.

Dumb Solid

A conversion of the geometry only, with no information about how it was created. Neutral files (IGES, STEP, etc.) are dumb solids. They create boundary curves along the edges, and boundary surfaces from all of the geometric features of the part and translate only these geometric features. This type of translation results in a solid model that is very difficult to modify. For example, if you need to change the location of a hole, you cannot redefine it with the CAD system and move it to a new location. You can’t even erase the hole. Dumb solids are OK if what you need is a 3D picture of the part. However, you will not be able to use the part as the basis for a new design, or revise the design. Dumb solid files are inadequate for real collaboration efforts because they don’t provide true interoperability between different CAD systems.

Feature-Based Native CAD Translation

The easiest way to define this type of translation is to ask the question, “how would the part look if you simply recreated the model from scratch with the target CAD application”? You would have native feature history, including how each of the geometric features were defined, parameters if applicable, and construction geometry where appropriate. The model file would be fully modifiable, and would be completely usable by the target CAD system. A true Feature-Based Native CAD translation allows full interoperability between different CAD systems.

ACIS

One of two prevelant mathematics kernels.

CAD

Computer Aided Design

CAE

Computer Aided Engineering

CAM

Computer Aided Manufacturing

DWG

Proprietary format used by Autodesk CAD System.

FEA

Finite Element Analysis.

IGES

Neutral file format - works well with 2d and wire frame data. Solid ability limited. Doesn't work well for associated entities.

Math Kernel

Math engine built into CAD programs. Software companies purchase kernels for their programs.

NURBS

Non-Uniform Rational B-splines

Para-Solid

One of two prevenlant model Mathematics Kernels.

SAT

Extension that's given to a pure ACIS file.

Sliver Faces

Surface patches that are much wider than they are tall. Often occurs when a modeler attempts to resolve the fit between big surfaces.

STEP

Neutral file format - defines fewer ways to create each type of geometry. Works better with 3D than IGES does.

STL

Stereo Lithography file format - another netural file format, created by 3D Systems, for the Stereo Lithography Industry (Rapid Prototyping).

Transition Cracks

Nearly invisible gaps between features of a model.

X_T

A version of a Para-Solid.

MRP

Materials Resource Planning

PDM

Product Data Management

Solid E

CATIA functionality that containts the complete geometry construction information.

Solid M

CATIA functionality. A type of dumb solid that is only a faceted representation of geometry.

Viewer

A tool that allows viewing of specific types of files with very limited functionality.

Neutral File Format

Generic term used by industry to signify a number of "standard" formats. Usually dumb solids that don't allow any real modifiability. Also prone to geometry errors (IGES, STEP, etc.).

Model History Tree

List of all of the geometric features or solids that make up a model file.

Parasolid

see Para-Solid.

Geometric Features

The individual geometric features that make up a part model. Protrusions, cuts, revolves, holes, etc.

Solid Feature

A feature that has solid mass properties. Also refered to as a solid.