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Intuitive modeler offers alternative to parametrics.
TODAY, MOST MECHANICAL CAD products are parametric, history-based applications. There are, however, some exceptions-IronCAD, ImpactXoft and CoCreate's One-Space Designer Modeling 2005. Designer Modeling is a 3D CAD tool based on a dynamic history-free architecture that can make it easier to modify 3D models because there's no need to know how a design was originally created. Co-Create calls this "intuitive modeling." It's a unique method for designing parts and assemblies, although it may put off some users at first-especially those who have experience and a comfort level with parametric, history-based systems. That said, parameters aren't always what they're cracked up to be.
The Parameter Dilemma
In parametric models, each entity, such as a line or a fillet, has parameters associated with it. These parameters control the various geometric properties of the entity, such as the width and height of a rectangle or the radius of a fillet. They also control the locations of these entities within a part model.
These parameters can (usually) be changed to create a desired part for design optimization while maintaining original design intent. History-based parametric modelers create and maintain a record of how a part model is built. When parameters in a model are changed and it regenerates, the CAD application repeats the operations from its history, using the new parameters, to create a new part model. An advantage for this type of modeling is that users can perform what-if scenarios and test various sizes of parts to determine the best one for a given purpose by simply adjusting a part model's parameters and regenerating the part.
Some parametric modelers also allow constraint equations to be added to models. These can be used to construct relationships between parameters. If several parameters always require the same value, or a certain parameter depends on the values of several others, this is the best way to ensure that these relationships are always correct. This ability, however, can also lead to problems, especially when changes are made to parts that are heavily parameter-dependent.
As you can see, though parametric history-based modeling can be a powerful design method, it can also quickly get complicated, and models created using this method can be difficult or impossible...