Shoe Design and Visualization

3 Modifying a Last Model
SHOE DESIGN AND VISUALIZATION WITH RHINOCEROS
As we have seen in previous chapters, last manufacturers and footwear designers make use
of existing lasts to develop a new last. They make modifications or blends between them to
adjust the last to new footwear models or to offer new aesthetic lines.
Modifying a last is a three-step process:
1 Split the last into two basic areas: a fixed part and a part to be transformed.
2 Make the modification on the area to be transformed.
3 Create a surface that blends between the two areas.
A similar procedure can be used to join a body from one last and the toe from a different
last.
1 Select a part to keep and a part to eliminate from each last.
2 Create a surface blend between the two parts.
When the modified last is made up of several surfaces, it is worthwhile to rebuild the last
following the procedures from the previous chapter to make a new last that consists of only
three surfaces.
We are now going to look at two typical modifications:
• Raising the heel
• Rotating the toe inward
The techniques described can also be used when blending two lasts.
Rhino deformation tools can also be used for aesthetic modifications.
Raising the Heel
To set the heel height, you will:
• Mark the last at the splitting point.
• Trim away a portion of the last between the forepart and the backpart to make room
for the rotation.
• Rotate the backpart to establish the elevation.
• Create a transition surface between the two parts.
Trimming the transition area from the last
The first step is to mark points on the last. You need a reference line that defines the center
of the transition between the forepart (toe section) and the backpart (heel section).
Copyright © 2005, Institute of Biomechanics of Valencia and Robert McNeel & Associates. 39