Hi David, and thanks for the lucid explanation.
So, I believe what your saying is that direct modelers such as Rhino (minus Grasshopper) and other such applications are non parametric, as unlike Solidworks there is no linkage to existing data, where the operations on one element of the relationship will propagate to the others. However doesn't Rhino have 'History' that works with a subset of rhino tools like 'loft' where a relation is maintained with the curves lofted? perhaps partially parametric...! Or perhaps a historical structure does not necessarily imply a parametric essence. Like yourself, I am still having trouble separating generative with parametric design. Surely the fact that software is parametric facilitates the possibility for generative creations? Dan On Mar 4, 2:51 pm, David Rutten <[email protected]> wrote: > Wikipedia: > > "The term "generative modelling" describes a paradigm change in shape > description, the generalization from objects to operations: A shape is > described by a sequence of processing steps, rather than just the end > result of applying these operations. Shape design becomes rule > design." > > Well, that's clear enough. I'm still having a hard time drawing a > sharp line between parametric and generative though. > > -- > David Rutten > [email protected] > Robert McNeel & Associates > > On Mar 4, 3:48 pm, David Rutten <[email protected]> wrote: > > > Hi Daniel, > > > a parametric modeler is one that's driven by parameters, as > > disappointing as it sounds. So, yes, on a basic level ALL modelers can > > be considered parameteric. > > However, that wouldn't be a useful term since it wouldn't exclude > > anything, so when we talk about parametric modelers we usually refer > > to indirect parameters. > > > For example, in Rhino you define a line segment by specifying the > > start and end point. This is typically not considered parametric. In > > Solidworks you can define a line segment as a tangent relationship to > > a circle and a certain length and angle. This would be considered > > parametric. One of the major outcomes of this different ideology is > > that parametric models tend to be history based. When you define new > > geometry using existing geometry, it doesn't take much to change the > > starting conditions and have the entire model adjust itself. So, I > > think most people will agree that in a non-parametric environment you > > directly design the model, whereas in a parametric environment you > > design the description of the model. In this light, Grasshopper is > > definitely parametric. > > > However, the term "parametric" has been applied to packages such as > > Solidworks and Catia and Pro-E for so long that it is now tightly > > associated with that particular style of interface. Perhaps this is > > why the term "Generative" has been introduced. To be honest, I don't > > exactly know what generative modeling is supposed to be. > > > -- > > David Rutten > > [email protected] > > Robert McNeel & Associates > > > On Mar 4, 11:37 am, daniel hilldrup <[email protected]> > > wrote: > > > > Hi All, > > > > I don't know if I am in the right place to start this debate, but I am > > > looking for answers > > > to my questions as I am about to undertake research on the field of > > > 'parametric' CAD design and am looking for some terminology > > > definitions. > > > > I am a MA product design student looking to adopt some of Grasshoppers > > > excellent > > > capabilities, and apart from the research would like to know how the > > > software is defined. > > > > OK my questions/statement: > > > > What is a parametric design? Is there a definitive definition? > > > At a fundamental level isn't all CAD parametric, using parameters that > > > state type, insertion point and direction (as with a line). Elsewhere > > > I see, dimension based modelers classified as parametric.... > > > > Is Grasshopper Parametric? I know that the 'blurb' states that it is a > > > Generative Modeler > > > using algorithms, so does it make it parametric? > > > > Would really appreciate any sources of information on the definitions > > > of generative/parametric modeling and the differences. > > > > Right, back to the hopper to see if I can make something from this > > > incredible software!
