Basics
ProTOp session concept

In ProTOp the term optimization session is used to denote the environment that:

• holds all model data and state parameters and
• manages all processes

related to a particular optimization task. Once a session is created, it contains a complete definition and current state of the optimization task. Within a session the optimization processes can be started, paused, and continued at any time. Meanwhile, the optimization task itself can be changed or upgraded as desired. The intent is to offer the designing engineer a powerful tool for efficient FEA-based design experimentation, prototyping, and finalization.

Session data and state

All session data can be classified into three main groups, as follows:

• FEA model data containing the complete finite element model,
• optimization model data containing configurators, technological constraints, etc., and
• setting and tuning parameters used to drive the optimization process.

When and how these data can be changed, depends on the session state. Any session exhibits one of the following three states:

• initialized state denotes a session with initial structural design (no optimization has been run yet);
• optimized state denotes a session with at least partially optimized structural design;
• running state denotes a session with an optimization process in progress.

The setting and tuning parameters can be changed at any session state, even during a running optimization process. The optimization model data can be changed anytime, except in the running state. The FEA model data can be changed only in the initialized state.

In ProTOp the FEA model data can be changed by various tools that operate on the FE mesh (mesh conversion, refinement, and stripping). In practice these tools can normally be engaged also in the optimized state of a session, e.g., after partial optimization. In this case, however, ProTOp will automatically generate a new session, which is actually a copy of the current session, but with its state changed to initialized. The engaged tool is then applied within the newly created session.

Active session

A ProTOp project can contain as many sessions as needed, but only one of those can be flagged as the active session. The active session is the one on which all ProTOp tools and procedures are applied.

New sessions can be generated either manually (on user request), or automatically (for example if the FEA model is about to change). In any case, the newly created session always becomes active automatically, while the previously active session is deactivated and saved for eventual later use. Of course, the user is free to change the currently active session as desired.