RealFlow’s timeline is not just a simple time indicator – it is a versatile tool that gives you lots of information about a simulation. The timeline slider can be moved back and forth and will let you preview the simulation, but only if the simulation data was cached to disk. In this case, calculated frames are shown in orange. Real-time playback is not always possible, because very large cache files need some time to be loaded, processed and displayed. If you need a real-time preview, please consider using RealFlow's preview tools and the “Movie Player”.
By default you can also see a range between 0 and 200. This is RealFlow’s standard simulation and playback range, depending on the appropriate preferences. Start and end frames for playback can be changed any time with the fields to the left and to the right of the timeline. The second field on the right is used to specify the simulation range. The default range for all projects can be changed under RealFlow's “Preferences”.
Next to the frame range input fields, there are two buttons. The first one will update the timeline – something you had to do manually in previous versions of RealFlow with Alt + U (this option is still valid). If you do not know what an update actually does, please have a look at the following example: Imagine you have completed a simulation, but forgot to save the scene before you quit RealFlow. When you open the project file again, it sometimes happens that the timeline is empty and does not show the orange progress bar anymore. At first appearance, it seems as if your cached data is lost and when you hit “Playback” or create a preview, nothing happens. Your simulation data is not lost, of course, and can be restored with the “Update Time Line Cache” button or shortcut. RealFlow now browses the project directories and looks for cache files. A cache file contains specific data and information making it possible to resume from a certain point in time. Please bear in mind that this process is not specific and there is no plausibility test: it might happen that results of previous simulations are shown as well if they have not been overwritten in the meantime. The second button moves the timeline slider directly to the last cached frame.
If you have imported an SD file for geometry or animation data exchange, there is always an animation range saved with the file, regardless of whether there are any animated elements in your file or not. This range can be defined by the user in the plug-in’s export settings. In this case, an additional line appears, indicating how many frames were imported/exported with the SD file. Please note that this line does not have any influence on the simulation length! It is just a visual control of how many frames have been stored with your imported scene.
Another feature of the timeline is the “Lock button” on the left. Beneath this button you can also find a little triangle. By clicking on it, a mini menu is opened, showing some options for locking a simulation:
Locking a simulation means freezing all previously animated transformations or movements. Imagine a filled glass is being poured out – the pouring is animated. The first step would be to fill the glass. By locking the simulation you can do this for an exactly defined range of frames (= “Frame countdown”). After the glass is filled with particles, you unlock the simulation and the animation can proceed. You do not have to specify a certain range for the countdown, because it is also possible to unlock the simulation manually by clicking on the lock button whenever you want it. With this easy method you can save time, because you do not have to split the simulation into two or more parts – filling the glass and performing the animation. All this can be done within a single file. In other words: locking the timeline prevents RealFlow from exporting any files. This is useful for simulating initial states. After you got the desired result, set the initial state for the emitter and reset the scene, unlock the timeline and simulate as usual. Now it will start from the initial state.