5 July 2011: Last week I had the chance to spend some web time with Paul Sagar, Director of Product Management at PTC. Paul is in charge of PTC’s surfacing and industrial design (ID) products. Paul’s background is in industrial design (ID) and design engineering in the UK and has spent about 11 years at PTC.
At PlanetPTC, Creo Freestyle was one of the many product announcements that struck me as fascinating. Just the idea of having incredible ID software as a freebie within Creo Parametric was one I wanted to explore further. After searching the PTC site for more detail with limited success, PTC’s VP and PR leader, Eric Snow, organized a web conference that “knocked my socks off!” You will see what I mean soon.
Immediate after my return from PlanetPTC I asked for a clarification as to precisely what Freestyle was and how it worked. Paul kindly responded with this piece of information –
- “Freestyle is a new feature inside Creo Parametric that allows for rapid freeform surface creation. It is built upon the concept of subdivisional modeling.
- The result of the Freestyle feature is a quilt of surfaces. The resulting surfaces or quilt can be added to, just like any other surfaces, with tools such as trim, merge, round, etc, or even thicken or solidify to make the model solid.
- When working with Freestyle you always have to start with a primitive shape. A gallery of primitives is available for you to choose from such as sphere, cylinder, circle, disc, etc.
- You are always working and manipulating the control mesh that surrounds the primitive. The control mesh can be subdivided up to add more detail or control. Adding more details allows for more control over the shape.
- The 3D dragger allows for quick and easy manipulation of the control mesh and consequently the resulting geometry shape. The resulting geometry is high quality, curvature continuous, manufacturable surfaces.”
Here is what I wanted to find out about on the call:
- What it does and what it cannot do,
- Where it fits competitively,
- How does it compare to a full ID system,
- How the designs get started and how they are stored within Creo, and
- What is sub divisional modeling?
Paul explained that Freestyle is a new freeform surface modeling capability added into Creo Parametric. Called a super feature within the model tree, Freestyle appears as a single feature with the tree. It’s almost like a modeling environment within a feature. It’s a simple and easy tool use, and is designed to be intuitive, interactive and quick. Targeted to industrial designers who want a tool to conceptualize but are not interested in the methodology of building surfaces, which has traditionally been done by building curves and surfaces from those curves. Modifications are made to the surfaces by going back and manipulating the curves. Instead Freestyle is designed to just deal directly with the shape. Thus users can concentrate on the form rather than what’s behind the form.
See the video of the bottle design that Paul downloaded.
The resulting surfaces generated by Freestyle are of high quality. You can take them directly to manufacturing. They can be thickened and brought directly into Creo Parametric as solids. They can be acted on as a normal solid with all solid modeling features, for instance, by adding ribs and bosses and holes. It can be brought directly into machining.
Surface manipulation. Can you control how the resultant surfaces by, for instance, controlling tangencies or other typical surface controls? His comment: “No. That is not how sub-divisional modeling works. It does not use normal surface patching techniques.”
A design starts with a primitive. Each primitive comes with a control mesh.
Creo Freestyle Primitives
Each mesh has edges, vertices, and faces. You can push or pull on them, or you can subdivide it. For instance, you can chose and edge and “split this edge,” and Freestyle will add more controls on that edge. The more controls, the more flexibility to manipulate the surface.
Each face of the control mesh corresponds to an actual patch in the resulting geom. that is created. Each patch is curvature continuous, resulting in a smooth model. Surfaces are G2 continuous, with some exceptions.
In the movie file of the bottle design, you should be able to see the design being developed. Unfortunately there is no audio file describing the workflow, but I am sure our readers can follow the concepts of Freestyle from watching the movie. Note that the design starts by building a solid model from a scanned sketch.
A sketch of the bottle
Trace Sketch allows importing the image and manipulates it, such as for fit or scaling, the objective being to use the image as an underlay for the design. A sphere is used to start designing the solid model using Freestyle. Special features during the process such as “connect” joins two faces together for completing the handle. Other operations such as a crease can generate either a hard or soft edge. Also note that Creo does not capture the history of the Freestyle design; only as a single Freestyle feature.
The 3D model of the bottle
Other sub-divisional modelers like Maya and 3D Studio Max, use sub-divisional modeling, but none of these modelers create NURBS surfaces — Creo Freestyle does. It creates regular Creo Parametric surfaces. Similar capabilities to Freestyle exist in Rhino’s T-Spline models and CATIA’s Imagine and Shape.
Conclusions:
- You can build geometry very quickly with Freestyle.
- It’s full integration with Creo Parametric integrates Freestyle design into the traditional design workflow.
- It has only a few commands and should be relatively quick to learn.
- The resulting geometry is of high quality and thus not throwaway work.
- The resulting surface geometry can be operated on directly using Creo Parametric surface commands or converted directly to a solid and manipulated with traditional Creo Parametric commands.
- With Freestyle free and relatively easy to learn, we recommend that users who do any industrial design begin using Freestyle right away.
