Mechanical Desktop integrates Auto-desk's mechanical design tools into a
consistent environment with capabilities ranging from 2-D drafting through
parametric solid modeling and associative assembly and drawings. It includes
AutoCAD R13, Designer R2 with assembly modeling, AutoSurf, IGES Translator,
PartSpec, and MaterialSpec.
Flexibility is Desktop's most impressive feature. While parametric and associative geometry can lead to a rigid, frustrating user environment, Autodesk has done an excellent job of avoiding these pitfalls. Notably, Desktop retains AutoCAD's robust undo capability, offers a wide variety of construction processes, and provides alternatives when drawing automation falls short of the user's intent.
Designer has matured significantly. Construction geometry is vastly improved in both capability and visibility control. Several tools virtually eliminate the need to repeat identical construction steps. Feature arrays assure efficient generation of repetitive geometry. Arrays are hierarchical so child features duplicate with an arrayed parent.
Designer now permits modeling underconstrained features, offering the ability to rollback to earlier construction steps and add constraints if needed. This permits quick conceptual work, with the refinement of fully constrained geometry only if the concept warrants the additional effort. This process can provide insight into preferable methods of constraint as well. In essence, Designer has significantly increased functionality while adding flexibility -- a noteworthy accomplishment.
Designer's associative 2-D drawing tools have matured, but less so than the construction tools. Drawings still require significant manual cleanup effort, leading to more rework than I'd like when features are edited. I'd appreciate a multiple sheet capability to minimize regeneration time for complex drawings. Although a work-around, Designer's 2-D drawing export provides a welcome safety net. A drawing may be exported as an editable, 2-D drawing at any point, providing the unlimited flexibility of 2-D editing to achieve the exact output desired.
Desktop's inclusion of AutoSurf and the capability of cutting Designer solids with surfaces is an important step in free-form modeling. Although surface cuts aren't parametric, Designer permits AutoSurf edits even after cuts are complete. Multiple surfaces can be used to generate thin shells and conventional features can be added to surface-cut features.
Assembly modeling is the newest Desktop tool. It manages local and external parts, assembling components with a reasonably intuitive constraint system. The assembler provides the basis for drawing management of large assemblies, and the sharing of details among many users. It permits simultaneous management of assembled and exploded views.
I created moderately complex assemblies of external parts and of single and nested subassemblies, and, in one case, replicated an assembly 16 times to generate a test of speed and clean-up capability. I was pleased with all results. Since many of my designs include closed-loop linkages, I hope that a future release includes a feature similar to 3D Studio's IK module.
While PartSpec and MaterialSpec provide insight into things to come, I believe that a 3-D parts database, with improved product-focused (rather than vendor-focused) search would be consistent with Desktop's powerful 3-D capability.
Desktop is an aggressive step in Autodesk mechanical design integration, providing marked improvement in Designer, and offering an essential capability in assembly modeling. I think it has been