As a designer, I would prefer to begin building models from drawings that are scanned into the system. There is an entire process for creating rough construction models that would give you that same lines that are shown below. This exercise uses data that is digitized from a sculpture because that is a common way for large studios to approve 3D properties for CG production. Since this exercise deals with surface construction, the way these lines are created is not important.
1. Pre-Build Your Surfaces.
Please examine the images below. The lines that were digitized are set up so the lines can easily be used to create surfaces. Note how the lines radiate from the eyes and mouth so they can create radial surfaces around those parts of the face. Whenever possible, try to determine ahead of time how the surfaces will be built, then digitize accordingly.
You can also use data that is digitized directly inside Alias using
the Microscribe utility. This utility can be downloaded from http://www.immerse.com.
It is called In-ScribeSGI.
|Digitized Data Front||Digitized Data Side|
2. The digitized data is imported as polylines.
The data can be imported as ".obj" or ".dxf" if you have polyline data to start with.
3. Import the file into Alias.
You will need to use the Alias file browser to locate the file in the file system. Once the file is loaded into Alias, you can open up the windows by using "alt-w" to open a 4-window view. This will allow you to view the data.
4. Convert the Lines into B-Splines.
If you digitized NURBS curves from inside Alias, or imported b-spline digitized data, this next step is not necessary. You should proceed to the next page.
Use Pick -> Object to select the polylines in the file. When all of the lines are highlighted, use Object Edit -> Fit B-Spline to create splines where the original digitized lines were.
It would be a good idea to pick the digitized lines again and save them for reference by using Object Display -> Tgl Template.