Software Lab 6-22-98

June 22, 1998 Design News

SOFTWARE LAB Reviews on tools of the trade

TurboCAD Modeler 2.0

Paris C. Altidis, Staff Engineer Borg Warner Automotive Inc.

TurboCAD Modeler has the Windows 95/NT look and feel. Its graphical interface features fully customizable toolbars, the modeling area, and an assembly tree that lists all parts and their features in the order created. All the tools in the TurboCAD Modeler screen offer context-sensitive help limited to the top level of each tool category. For a first-time user of the product, this can be a nuisance, especially when going through the tutorial lessons.

As a true feature-based program, TurboCAD Modeler lets you create parts from 3D primitives, or start from a 2D profile that can be extruded, revolved, or swept to create the 3D part. IMSI has included a wide array of 2D and 3D entity tools in an easily accessible toolbar. Tools like lofting and shelling offer functionality when modifying features in parts.

Correct dimensions are not important in the early stages of part creation since the part is driven by features that can be constrained in several ways. In its simplest form, TurboCAD Modeler will create a part such as a circular plate from a 2D circle, then extrude it, add fillets to smooth the edges, and maybe punch some holes in a specified pattern. Every operation in this scenario adds a feature to the assembly history tree. When the part is complete, you can locate a feature in the tree and modify every aspect of it, such as the thickness of the plate or the number of holes. In some cases, the assembly tree can be re-arranged simply by dragging and dropping features.

Constraints and assemblies. In TurboCAD Modeler the constraints are displayed with symbols that sometimes are cryptic in figuring out the constraint parameters. Three-dimensional constraints apply in assemblies to define the placement, alignment, or mating surface definition of the constituent parts. TurboCAD Modeler is built with a bottom-up architecture, and that sometimes can hamstring the creation of assemblies done after the parts are built. Although the constraint tools give you enough flexibility to properly position the parts, there are occasions when the assembly cannot be completed without some sort of cutting/pasting, or even positioning the part with only manually imposed constraints. The complete assembly can be checked for interference.

Drawings in TurboCAD Modeler can only be created using its 2D counterpart, TurboCad Professional, which requires a separate installation. The feature-based definition stops as soon as you export the views from the TurboCAD Modeler. That leaves you with two separate parts that can be edited independently without changes reflected in either direction (3D to 2D or vice versa). The exported views can consist of layers so that line and color attributes, as well as hidden lines, are preserved. The preferred format is DWG or IGES, since other methods such as SAT give you a 2D representation of the 3D part and redundant lines that are used to define the 3D surfaces.

TurboCAD Modeler includes a tutorial that covers almost all the features the program has to offer. However, lack of context-sensitive text for every level in any of the toolboxes makes it difficult to follow. Perhaps one of the most powerful features (but yet undocumented) is the use of Corel Script to automate the TurboCAD Modeler functionality. The novice as well as the experienced user will appreciate its usefulness because he or she can record the key and mouse sequences or write the code in an easy to learn language that is reminiscent of Visual Basic.

TurboCAD Modeler offers tools that are superior in some areas for its price range (about half the cost of most mid-range CAD software), but it lacks features like solid model/drawing integration offered in other full-fledged solid modeling programs. Adding documentation and some assembly management tools (such as BOM) currently included only as script examples would definitely enhance the value of the program.