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Revcad have introduced their new RAD CAD technology in the new version of their flagship product Sheet Lightning (Version 5.0 and Lite 5.0) for specialized sheet metal design of ducting, flues, chutes, hoppers,
feeder, silos, tubular steel design and related products.
What is RAD CAD?
RAD CAD is ‘Rapid Application Development for CAD applications’. It is based on a philosophy that reduces a complex design process to its simplest form for specific products, while at the same time
providing lower and more flexible (and more complex) design levels.
Using RAD CAD technology a CAD ‘expert’ can create designs at the lower level, then raise them to a higher level for the ‘non-expert’ to use. The lower level may require 3D CAD skills but
designs that are promoted to the higher level can be left in the hands of a novice. The skills of the expert are then only required when the design changes its fundamental form in some way. If the required design is
simply a variation of the original it should be completely definable at the higher level.
RAD CAD Design Levels
A higher RAD CAD design level may reduce a design problem to simple parameters such that the design process requires no more than typed dimensions. At the same time RAD CAD technology maintains the availability of
lower CAD levels that provide tools and facilities closer to a general 3D CAD system. A key feature of RAD CAD with its multi-design levels is that designs can be created at the lower level then promoted to a higher
level by applying specific analysis rules. The design can then be manipulated at the higher level and added to the design library such that it can be recalled and modified by typed dimensions only. At any time the
design can be demoted to a lower level for the design process to continue using more general CAD tools.
Parametric design technology has been around for a while in various forms and is appropriate for many design problems, but it has its limits. Parametric technology begins to hit significant barriers as the design
complexity increases and the number of design variables increases. In fact there tends to be an exponential increase in the parametric complexity as the number of components in the design increases. RAD CAD answers
the problem with design levels that go higher still.
RAD CAD Language?
The highest design levels of RAD CAD technology involve the invention of language. CAD systems provide macros and/or an open software architecture to access their basic command structure. All this serves to
radically increase the potential of the CAD system, but the language very rarely rises far above the CAD system command level. The design of macros and ‘application’ software tends to start at this basic
command level and lift the command level to new heights by combining them to form new and more powerful commands thus extending the command structure. Often this means an impressive speed increase and is a step in
the right direction for incremental increase in speed and productivity.
RAD CAD takes a very different approach. It begins by examining the actual design product and asking ‘What is the most convenient and meaningful way of defining both the design and the design process for this
particular product?’ Parameters may be sufficient to define the final design but what do they say about the design process. For example the CAD level does not understand the concept of a ‘support’,
whereas the product level may understand the concept and therefore is able to ensure that the design component conforms to the conditions and behaviour required by a support.
RAD CAD is geared to the invention of a ‘product language’ that defines and encapsulates the design process, not primarily in CAD system level commands, but primarily in ‘product
commands’. The CAD level commands that actually create the CAD design represent a lower language level to which the design may be downgraded if required, such that work can continue at the lower level. The
language system may embed several language levels between the ‘product language level’ and the fundamental CAD command level, including the parametric level.
RAD CAD in Bespoke CAD Application Development
Revcad specialize in developing specialist CAD application software. Their RAD CAD tools have been created specifically to bring the possibility of bespoke engineering CAD application development for complex
design within a cost effective timescale. As a result they are rapidly expanding their specialist product capability for designs as diverse as lamp shades, bouncy castles, structural steel supports for building such
as football stand and others. For example the flagship product Sheet Lightning includes special design features relating to the product for ‘pressure vessel’ design and complex multi-intersection
‘feeders’.
Levels and Concepts of RAD CAD
The lower RAD CAD application levels often combine selective parametric design with general 3D CAD design. 3D design can be notoriously difficult, but in many cases the reason for the excessive difficulty is that the
design process has been forced to fit into a particular low level design philosophy of a general CAD system. RAD CAD technology breaks out of these restrictions and provides the user with 3D design that can have its
most convenient form for the particular product in question. The following features are standard during 3D CAD design and simplify it greatly:
1. RAD CAD 3D tools are accompanied by equivalent dialog controls which can do everything that could be done in the 3D view.
2. The motion and events of the 3D cursor is often controlled or restricted by RAD CAD, rather than the perpetually liberal movement in a normal 3D CAD system.
3. Color coded object highlight prompts are constantly made for valid object selections along with textual prompts when using RAD CAD 3D tools to guide the user as closely as possible through the design process
and the use of a tool.
4. Already mentioned - the design process can be raised and lowered through various CAD levels ranging from entirely parametric to general 3D CAD.
5. Language invention (as discussed above).
The future of RAD CAD will be able to use the open architecture of general CAD systems (such as Autocad) in such a way that it uses the CAD system as its graphics engine. The whole
application will be able at any time to be pulled away from the CAD system and provide its own higher level design tools where required, or alternatively is can selectively override the more complex parts of the
design process. Currently the integration of Revcad’s applications to general CAD is via a seamless export of CAD data only.
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