System Controlled Functions

~ ~ Some of the functions that go into designing a tower have been left for SNEAKERS to handle. This is due to several factors, including the problem of handling all of the user's possible requests. By controlling some of the functionality, SNEAKERS is better able to guide the designer in the design task, rather than requiring the program to be an arbitrary drawing program.

Design Phase:

The progression of the design from Abstract through Intermediate to Detailed is controlled by SNEAKERS. The user must follow this path and cannot skip a step in this progression. The user decides when a level of the design is completed, but SNEAKERS changes the interface to reflect the new level. This change sets up the widgets needed to get input at this next level. This guidance helps to focus the design, and does not allow the user to change focus except by restarting the design.

Component Selection:

The system will only allow components to be added in a prescribed order. A connector can only be placed on top of a support. If no supports have been placed, or all supports have connectors, no new connectors may be added. Except for the initial supports, which must be placed as prescribed by the abstract tower, all supports must be placed on top of another support which has a connector already in place. This helps keep the design correct, i.e., no unconnected supports on top of each other. It also helps guide the design so that it follows the pattern of the abstract tower.

Component Positioning:

The supports are placed on top of each other at various angles. The angles to be used are determined automatically by SNEAKERS to help follow the abstract tower. This is a four step process:

1. The system determines the ideal angle from the end of the last support to the designed top of that leg of the tower.
2. The ideal angle is compared with the allowed angles as determined by the type of connector being used to connect the two supports.
3. The closest allowed angle to the ideal angle is chosen.
4. The support's end point is determined based on the chosen angle and the support's length, and the support is placed.