I am a newcomer to the realm of CAD/CAM and willingly to understand the rules of this field as soon as possible. I think most of the CAD packages concentrate on graphical task, but what about numerical computations? Typically those "what-if" problems. What kind of softwares are suitable for this purpose? Thx!

Not sure whether you're really talking about determininng theoretical "fit" between parts, or about statistical process control methods for determining fit, about determining structural strength or thermal or fluid dynamics based on 3D CAD models, or about mathematical models that solve problems like in optics or for wave propagation/deflection, etc., or more about how to reverse engineer complex geometry. If the former, then SolidWorks gives you the tools to determine proper geometry for very complex fit scenarios -- including semi-automated interference checking -- although it won't tell you how much actual clearance you have. The "Measure" tool has to suffice for much of that, but you can easily create a model of one part BASED ON another part, with offsets for sketches upon which features are based. You can even offset features/surfaces to create new derived and dependent parts and assemblies. And those capabilities allow one to define accurate theoretical clearances, although real-world clearances have to be determined based upon knowledge of manufacturing process and achievable tolerances.

Of course statistical process control methodology and SPC softwares (that are definitely separate from SolidWorks and other 3D MCAD software) are used extensively in industry to determine what is achievable and how to refine processes and designs for achievability. There is SOME software available as add-ons to 3D CAD programs to help determine proper tolerancing to help ensure fit for 2D CAD drawings generated from 3D models of parts, but mostly engineers just rely upon their own understanding of processes and proper tolerancing to create drawings that have a high probability of resulting in good parts.

Finite Element Analysis (FEA) for strength and thermal / fluid dynamic analysis for heat transfer and flow optimization are handled by separate softwares that may be integrated into a 3D CAD environment or may take output from the 3D CAD software for use in independent computation.

For physics including things like optics, wave propagation/deflections, etc., and other theoretical computational mathematics most engineers use software such as MatLab, Mathematica, FEMLAB and some others.

Reverse engineering complex geometry is mostly the domain of sophisticated hardware (like CMC and laser scanning equipment) which generate large amounts of data obtained from objects, which in turn is imported into and analyzed with sophisticated softwares which are complementary to (but separate from) 3D MCAD applications. As with FEA and thermal or fluid dynamic analysis softwares, some of that is written to be integral to a particular 3D CAD environment, and some of it simply outputs data that can be imported into the 3D CAD softwares.

Thanks a lot, Sporkman. But I still have some questions to expand. For example, I want to figure out the maximum volume of a conical machinery unit which the height and the area of the bottom face are the given arguments? By what means or what kind of tools engineers usually use? And after your expanation, I have a strong interest about the ecosystem of a CAD design procedure. As you metioned above, a lot of different softwares involve along a project. Usually engineers will have what weapons to comprise their arsenal? SolidWorks+Mathematica+Ansys+3DS+....?

Thanks a lot, Sporkman. But I still have some questions to expand. For example, I want to figure out the maximum volume of a conical machinery unit which the height and the area of the bottom face are the given arguments? By what means or what kind of tools engineers usually use? And after your expanation, I have a strong interest about the ecosystem of a CAD design procedure. As you metioned above, a lot of different softwares involve along a project. Usually engineers will have what weapons to comprise their arsenal? SolidWorks+Mathematica+Ansys+3DS+....?

: wrote : I am a newcomer to the realm of CAD/CAM and willingly to understand the : rules of this field as soon as possible. I think most of the CAD : packages concentrate on graphical task, but what about numerical : computations? Typically those "what-if" problems.

Pro/e has Behavioral Modelling, meant exactly to deal with modelling 'what if' problems. This function of Pro/e is used extensively to setup and run design studies for optimizing designs by a set of parametric (usually numerical) criteria. You can begin with a Sensitivity Analysis to see which of parameters has the greatest, which the least impact on the desired outcome. You can then proceed with a Feasibility/Optimization analysis which takes your design goals and varies the parameters, incrementally, within prescribed limits, to test either feasibility or to optimize the design. This can be done in conjunction with Mechanism Design to vary models and test their effect on a mechanism or in conjunction with Mechanica to test changes of part configuration on loading/stress, for example. And finally BMX allows you to conduct Multi-Objective Design Studies which lets you set up several goals and chart to solution of each plus make comparisons between them, IOW, several optimizations simultaneously. In both optimization analyses and MODS, the results can be used to modify the models according to the optimized results, including when done in conjunction with MDX or Mechanica.

There is a formula for that or something similar: redo the area-of-a-circle formula to get the radius of the bottom face, the CRC Math Tables book likely has a formula for cone volume given radius and heigth. If you study enough math (perhaps it's spelled maths where you are), especially through calculus, you should be able to derive such a formula yourself. You can also do this numerically, and probably some programs will do this for you for arbitrary shapes, but if an exact formula can be used, it's the preferred method (at least by me), though on second thought I'd use both methods to be sure they agree.

If you want numerical computations, write a program or procedure using the required formulae in VB or Delphi or any other high level language and compile to a .exe file.

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Hide Corp has a product called Intent which is a knowledge based design iteration program. It is imbedded into Unigraphics as Knowledge Fusion. Pro/E has the Behavioral Modeling Extension package.

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