In a press release this week coinciding with EuroMold 2010 in Frankfurt, Delcam, a UK-based CAD/CAM software company, announced the release of PowerSHAPE 2010. I have always been intrigued by PowerSHAPE mainly due to the fact that it is a surface modeler, and not a solid modeler. All solid modelers usually tend to behave in a similar fashion. On the other hand, surface modelers tend to vary a great deal. But now, as far as PowerSHAPE is concerned, that appears to be changing. PowerSHAPE 2010 is the version when Delcam has started using the Parasolid solid modeling kernel from Siemens PLM. The interesting part is that Parasolid has not replaced PowerSHAPE’s existing modeling kernel, but rather sits alongside it.
If you are not completely aware of the difference between a surface modeler and a solid modeler, you may find this interesting. Basically, surface models describe the external surfaces of an object by means of trimmed surfaces like NURBS Surfaces, Coons Patches, Bezier Surfaces, etc. and sometimes even curves. These models need not be watertight, ie. form the boundary of a closed volume. On the other hand, solid models always describe a closed volume and are strictly watertight. Surface modelers usually start with curves which are swept, extruded, etc. to result in surfaces, which then may or may not be sewed together to yield the final surface model. Solid modelers usually start with a bunch of closed curves (a sketch) which is then extruded to yield a watertight solid. From there on operations are carried out on the solid to always result in a solid.
Solid modelers are good at designing prismatic objects like those used in mechanical engineering, but not very effective when it comes to creating aesthetically pleasing “sexy” surfaces. A good example is Matt Lombard’s recent modeling challenge where he challenged SolidWorks users to SolidWorks’ Freeform tool to take a surface and deform it freely to result in a human face. As you can see from the images of faces on his post, this kind of stuff is not easy to do in a solid modeling system like SolidWorks. From what I can guess, the images that look more like human faces are actually very good surfaces already brought into SolidWorks and then tweaked a little.
On the other hand, surface modelers find it difficult to do solid modeling-like operations like shelling simply due to the fact that they first need to close them into watertight solids. Of course, surface modelers can cut, trim and extend faces of non-watertight surface models. But that sometimes can lead to undesirable results since they are mostly bothered with the surfaces that are in the proximity of the area of interest and not the entire model as a whole.
Delcam has been developing its home grown surface modeling kernel for the past 30 years. Just by that I am assuming that their stuff must be good. And that is precisely what I intend to find out in this series. But if their stuff is good then why have they added the Parasolid modeling kernel to PowerSHAPE 2010? We will find out why in the next part.