## Model states |

OrcaFlex builds a mathematical model of the system being analysed, the model being built up from a series of interconnected objects, such as lines, vessels and buoys.

OrcaFlex works on the model by moving through a sequence of states, the current state being shown on the status bar. The following diagram shows the sequence of states used and the actions, results etc. available in each state.

Figure: | Model states |

The model states are as follows:

The state in which OrcaFlex starts. In reset state you can freely change the model and edit the data. No results are available.

OrcaFlex is performing the static analysis of the model. You can abort the calculation by clicking the reset button.

The statics calculation is complete and the static position results are available. You are allowed to make changes to the model when in this state but if you do so (other than very minor changes, such as pen colour) the model will be automatically reset and the statics results will be lost.

The dynamic analysis is in progress. The results of the simulation so far are available and you can examine the model data, but only make minor changes (e.g. pen colours). You cannot save the simulation to a file while calculating – you must pause the calculation first.

The dynamic analysis has begun, but it is paused. The results so far are available and you can examine, but not significantly change, the model data. You can also save the part-run simulation to a file.

The simulation is complete. The simulation results are available and you can store the results to a simulation file for later examination. You must reset the model before significant changes to the model can be made.

You can use the extend dynamic simulation facility if you wish to simulate for a further period of time.

The calculation has become unstable. The simulation results are available and you can store the results to a simulation file for later examination. This allows you to examine the results up to the point at which the simulation became unstable, to try to understand the reasons why. However, please treat these results with caution – the simulation going unstable indicates that the dynamic calculation may not have converged successfully at earlier simulation times.

You must reset the model before significant changes to the model can be made.

To illustrate how model states work, here is a typical working pattern:

- In
**reset**state, open a new model from a data file or use the current model as the starting point for a new model. - In
**reset**state, add or remove objects and edit their data as required for the new model. It is generally better to use a very simple model in the early stages of design, only adding more features when the simple model is satisfactory. - Run a static analysis (to get to
**statics complete**state) and examine the static position results. Make any corrections to the model that are needed – this will automatically reset the model. Repeat steps (2) and (3) as required. - Run a simulation and monitor the results during the calculation (in
**calculating dynamics**state). - If further changes are needed then
**reset**the model, edit the data accordingly, and repeat steps (2) to (5) as required. - Finalise the model, perhaps improving the discretisation (by, for example, reducing the time step sizes or increasing the number of line segments). Run a final complete simulation (to reach
**dynamics complete**state) and generate reports using the results.