Part VII: Working with Specialized Functionality
Defining the role of direct edit tools
But direct edit CAD software has not taken over the market, even with all of the recent hype.
History-based modelers still dominate. There must be more to this story: the direct edit scheme
does have some weaknesses. While making individual changes is easy and intuitive, making con-
ceptual changes (changes to the design intent) is just like starting over again with direct edit. There
are also situations in which certain edits cannot be made, or reversing a set of edits does not result
in the original configuration. People who are used to the control and power of history-based sys-
tems are not going to relinquish that control for simple ease of use.It turns out that the simplified capabilities of direct edit tools are more suited to non-CAD special-
ists who still need to work with geometrical data either upstream or downstream from the main
production modeling. This means that a non-specialist can do the equivalent of a 3D napkin
sketch in Sketchup and hand it off to a specialist to add the details. It means that an FEA (Finite
Element Analysis) analyst can make simple edits to a model given to her by a specialist. A machin-
ist can add stock to a finished detail model without being highly CAD proficient. I don’t see CAD
power users or production modelers giving up history-based CAD software and changing over to
direct edit tools any time soon.As a part of the direct edit resurgence, CAD companies have figured out how to apply the concept
of parametrics (driving dimensions and geometrical relationships) directly to the solid model. Also,
the history-based modelers are adding some direct-editing functionality. This cross-pollination
helps bridge the gap that is now becoming mainly a discussion about history-based and history-
free CAD systems. In this chapter, I do not cover the details of how each CAD company has imple-
mented the direct editing scheme, I just want to help you understand where SolidWorks is today
in the direct edit spectrum, and what you might have to look forward to as the comparison
between the history-based and history-free worlds continues to take shape.This background information is important as a part of the overall discussion of the place of these
tools within the SolidWorks software. Adding direct edit tools to SolidWorks is not an earth shat-
tering change, but of secondary importance. Notice that the topic of direct edit does not dominate
this book, just one chapter out of 33. SolidWorks includes the tools because they are useful, not
because they are necessary.Understanding the strengths and limitations
of direct edit tools
Some of the selling points for the direct edit CAD tools are that you don’t have to worry about how
a part was made (you just make the changes you want to make), and that feature trees with “his-
tory” always include feature rebuilds (which users tend to complain about taking a long time, espe-
cially for large parts and assemblies).Without a doubt, grappling with feature order and feature rebuild times are problems that
SolidWorks users face daily and often complain about.