A polygon mesh is output from a reverse engineering device. Once you use PowerSHAPE to fix holes quickly and accurately, you can combine scans as shown in this intersection between scans. A standard liner is created using a composite curve created from surface and polygon data.
If you are new to Delcam, you’re in for a treat. While the company is perhaps best known for its manufacturing applications such as PowerMILL (CAM) and PowerInspect, Delcam also offers design tools that it has been developing rapidly. The range is comprised of the hybrid-modeling system PowerSHAPE, CopyCAD for reverse engineering and polymesh wrangling, and ArtCAM for decorative 3D design. But what’s most interesting is that Delcam has now integrated PowerSHAPE (reviewed in DE, Nov. 2006) and CopyCAD into a single application to overcome problems found in most reverse engineering software.
As viewed by Delcam, these obstacles involve capturing and refining data and Delcam’s new solution does it very well. But typically any subsequent work requires that the data be transferred into a separate CAD system — and PowerSHAPE does this as well. So, to look at how this new combination works in practice, we’re going to step through a customization project, incorporating surface modeling, polygon mesh handling, and integrating a sculpted decoration on a motorcycle helmet.
A Perfect Fit
Let’s begin by taking a standard helmet design and adapt it to user’s requirements both in terms of fit and function as well as decoration. Since we’re talking about a safety product, fit and function must come first.
ArtCAM is used to take a 3Dmodel, flatten it, add more detail, and then copy and paste the design into PowerSHAPE.
The process begins with a scan of the customer’s head, a process always prone to holes that need to be patched. The good news is that PowerSHAPE now offers the polygon mesh handling tools from CopyCAD, allowing you to work with polygon mesh data from a reverse engineering system alongside surface and solid data. The Hole Filling tools are used to remove these gaps and to fill in the spaces.
PowerSHAPE offers tangency control to ensure that complex surface relationships are maintained while a planar cap can be used for more structured forms. The CopyCAD tools allow you to work with and refine the forms. Smoothing is interactive, with control over strength and smoothness, and geometry can be raised or lowered to achieve the desired shape. The cleaned-up head scan is then positioned relative to the standard helmet model and the intersection found between the head data and original helmet liner.
What’s important to note here is that you are using a mix of surfaces, polygon data, and composite curves generated by the intersection of both, all with the aim of creating a form that fits the customer. This is a recurring theme: using the data you have to achieve the end result you want.
The final object, adapted from a standard product to one adapted for user fit, is decorated in the manner requested by the customer.
For example, once you have the polygon-based liner in place, you then use the dynamic sectioning tools to create a series of sections through the polygon mesh. This is automated from a simple dialog that creates a grid of sections in a single operation. You then use that curve network to create a high-quality surface, delete the underlying polymesh, and create a slight offset to fit the head perfectly.
A Simple Command
The next stage shows off some tools that, while not unique, have been mastered by Delcam over the last few years. Call it Global Shape Modeling, call it Morphing, the point is the same — you can take a highly accurate surface set and make local modifications to that data, ensure that tangency and curvature are maintained, but still add some shape.
In PowerSHAPE, you have the ability to take a surface set and use the tools to define exactly what morphs you want, what geometry is affected, what isn’t, and how the transition between the two areas are handled. In our example, the morphing tools were used to create a more peaked version of the helmet. You can do this using two reference curves — the first of which resides on the start geometry and the other describes the final ‘destination’ for the surfaces. Or you could use the move command to shift selected geometry.
Adding Details For Customizing
While you can add form using surfaces, if you wish to create a differentiated product, that may mean complete personalization and adapting the product to the user’s lifestyle. To do this, you can take advantage of the ArtCAM component, which is used to create complex 3D reliefs in many creative industries, such as sign-making, jewelry, and giftware. These are built up using a series of 2D boundaries, extracted from a bitmap image, sketched by hand, or created with an STL file of a 3D object.
In this case, we worked with a 3D STL file image of a skull and flattened it in ArtCAM. We then used the tools to adapt it and refine it (to add detail and such) to create exactly the form we required.
All of the tools are very interactive and essentially help you sculpt the relief model. Once that’s complete, the final stage is to adapt this planar 3D relief to the form of your product. You copy and paste it from ArtCAM into PowerSHAPE, use the wrapping tools to position and scale it accurately to create the look you want, and instruct the system to apply it to the surface model. The system then trims out a portion of surface model to fit the triangle model into it. The end result is a helmet that’s not only adapted to the user’s physical characteristics, but has also been speedily customized.
Value Added Up Front
The product we've looked at is PowerSHAPE, which now integrates the CopyCAD tools within it. While we haven’t touched on the pre-existing tools much, the automatic surfacing technology Delcam introduced last year offers you surface creation workflows that are much more efficient with all of the additional tools you need to create the forms you want. Very few other systems can provide that capability easily, even if they have the basic underlying technology to do so.
So, why would you add PowerSHAPE to your toolset? Well, first of all, if you are currently using reverse engineering tools to capture and refine scan data to the point of very high-quality meshes, you might not have the powerful tools necessary to create the very high-quality surfaces. With PowerSHAPE you can integrate the two. Secondly, you can create design variants easily and within minutes based on a modular design. As we’ve seen in this example, swapping detail in and out is seamless and you can generate radically different design iterations with ease.
With the rise of high-volume manufacturing in emerging regions, the question for many western organizations is how to differentiate their products. By way of customization and design iteration, you can add value to your products and services without contributing to a high overhead in terms of upfront design work required to create models from scratch. Delcam’s system is uniquely positioned to enable that at the front end of the design process.
Contributing Editor Al Dean is the editor at DEVELOP3D, a new UK product development and manufacturing technology journal (develop3d.com). He divides his time between daydreaming about owning a 5-axis NC machine and having nightmares explaining its purchase to his family. Send comments about this article to DE-Editors@ deskeng.com.