**4.5 Solid model export**

180 Reverse Engineering – Recent Advances and Applications

*Analyzer*. The solid model generated is extremely accurate, where geometric error measured in average and standard deviation is 0.0002 and 0.0017 in., respectively (between the solid model and point cloud). Since the model is fully parameterized, it can be modified by simply changing the dimension values. For example, the length of the base block can be

*Wizard*, or *Modeling Wizard*, of *Rapidform* automatically extracts *Wizard* features such as extrude, revolve, pipe, and loft, etc., to create solid models from segmented regions. Note that a *Wizard* feature can be a surface (such as pipe) or a solid feature. There are five *Wizard*  features provided: *extrusion*, *revolution* for extracting solid features; and *sweep*, *loft*, and *pipe*  for surface features. There are three general steps to extract features using *Wizard*, (1) select mesh segments to generate individual features using *Wizard*, (2) modify the dimensions or add constraints to the sketches extracted in order to parameterize the sketches, and (3) use Boolean operations to union, subtract, or intersect individual features for a final model if

The same *tubing* example shown in Fig. 19 is employed to illustrate the capabilities offered in *Wizard*. We start with a polygon mesh that has been segmented, as shown in Fig. 19a. First, we select the exterior region of the main branch and choose *Pipe Wizard*. *Rapidform* uses a best fit pipe surface to fit the main branch automatically, as shown in Fig. 19b. Note that the *Pipe Wizard* generates section profile and guide curve as spatial (non-planar) spline curves, which cannot be parameterized. Also, wall thickness has to be added to the pipe to complete the solid feature. Next, we choose *Revolution Wizard* to create revolved features for the top and bottom flanges, as shown in Fig. 19c. Note that each individual features are extracted separately. They are not associated. Boolean operations must be applied to these

Fig. 19. Feature extraction for the *tubing* example using *Wizard*, (a) selected main branch region, (b) surface created using *Pipe Wizard,* and (c) flange created using *Revolution Wizard*

Although *Wizard* offers a fast and convenient approach for solid modeling, the solid models generated are often problematic. The solid models have to be closely examined for validation. For example, in this *tubing* model, there are gap and interference between

increased for an extended model, as shown in Fig. 18c.

decoupled features for a final solid model.

**Method 2: Wizard** 

needed.

The solid models created in specialized software, such as *Rapidform* and *Geomagic*, have to be exported to mainstream CAD systems in order to support engineering applications. Both *Rapidform* and *Geomagic* offer capabilities that export solid models to numerous CAD systems.
