To play a simulation
- If the TimeLiner window is not already open, click Home tab  Tools panel Tools panel TimeLiner TimeLiner . .
- On the Tasks tab select the Active check box for all tasks that you want to include in the simulation. 
- Be sure the active tasks are assigned the correct Task Types. 
- Be sure the active tasks are attached to geometry objects, and click the Simulate tab. 
- Click the Play   button. button.The TimeLiner window displays the tasks as they are carried out, and the Scene View shows the sections of the model added or removed over time, in accordance with the task types.  
Note: When the 
Simulate tab is in use, by default the current simulation date is overlaid in the 
Scene View. You can customize the displayed information by using the 
Overlay Text Dialog Box.