A replay is a sequence of 3D views shown one after another to give an animation. A replay is therefore like a short length of film, with each frame of the film being a snapshot of a model as it was at a given time. There are various controls and parameters that allow you to control a replay. Replays are a natural result of time domain simulation, but it is also possible to synthesise replays following frequency domain simulation.

Replay type

Active simulation replay times

There are two options for specifying the times used for an active simulation replay:

Export video

Replays can be exported as either AVI files or as PDF files, using the export video button on the replay parameters form. The generated file uses the view parameters of the most recently selected 3D view window. For PDF output you can specify how many replay frames are output on each page of the exported PDF document.

When you export a video clip you will be asked to select a file name for the video using the standard save file dialog. If the add program/file details to output preference is enabled, then each frame in the video has details of that frame (e.g. simulation time) written in the top left-hand corner of the frame.

AVI is a standard video format, so the file can then be imported into other applications, for example to be shown in a presentation. Note however, that AVI is what is known as a container format. So whilst the AVI container format is well known and understood, the video stream inside the container is compressed using a codec. Different AVI files can use different codecs and so it is possible for a machine to be able to play some AVI files and not others, depending on which codecs are installed on the machine. In order to play the AVI file you will need to ensure that the codec used to generate the video file has been installed on the target playback machine. The codec used for generating the video file can be set on the preferences form.

Note: AVI files can be very large if the window size is large or there are a lot of frames in the replay. Also, resizing video clips (after pasting into your presentation) will introduce aliasing (digitisation errors), so it is often best to set the 3D view window size to the required size before you export the video.