CopyCAD's new triangle modelling tools
allow complete designs to be
produced from incomplete scan data |
CopyCAD’s new modelling tools permit the creation of a range of primitive geometric shapes, including spheres, cubes and cylinders. While these mean that the software could be used as a complete triangle modelling system, it is expected that most applications will be in the completion of reverse engineered models.
A typical example would be in the plastics industry, where initial hand-modelled prototypes are often produced in solid material. Reverse engineering from such models will only produce the external surfaces of the component. However, within the new release of CopyCAD, these surfaces can be offset by the material thickness to generate the internal surfaces. Extra geometric features, such as reinforcing ribs and bosses for fixing, can then be added to complete the model.
Other improvements in the new release include the ability to refine the triangles created from the original data, either across the whole model or in a specified area. This facility will help in the generation of a smooth horizon line when creating mould designs from triangle data, especially when starting from models made up of coarse triangles.
CopyCAD has been able for several releases to fill holes in the model resulting from missing or sparse data. This functionality has now been improved by adding the ability to use multiple patches to fill the affected area. The use of multiple patches will give closer tangency matching to the scanned data, especially in regions with large curvature changes, with no gaps or overlaps between the new surfaces generated and the remainder of the model.
The latest CopyCAD release comes at a time when there is a resurgence of interest in reverse engineering, after a period when it was widely believed that the technique would be replaced completely by computer-based design methods. This renewed interest was highlighted last year when CopyCAD was the winner of the Desktop Engineering Readers’ Choice Award for October.
Even those companies using CAD successfully for the majority of their modelling requirements still have some designers working with very complex shapes that prefer to produce models by hand. The time and effort needed to retrain those people in new computerised design techniques may make it impractical to change their working methods, especially if they are reluctant to abandon their original skills. Often, it is easier to leave such craftsmen to work with their traditional methods and capture the results with reverse engineering to generate CAD models.
Of course, a combination of both techniques can be used to obtain the final CAD model that is needed. For companies that wish to work in this way, Delcam’s Total Modelling approach to design allows users to build up CAD models quickly and easily with data from different sources. For example, Total Modelling makes it simpler to design the main outline of a product with CAD, but use hand models for complex details or decoration. The hand-modelled sections can then be digitised and combined with the main CAD model in the computer.
A similar approach can be taken when developing “new” parts that are, in fact, variations on existing components. It is often quicker to digitise the existing part and limit the CAD work to the desired modifications, instead of completely recreating the whole part with CAD. |
