The script is a file that provides directions about what we do, and in what order, in other word an Animation. The following is the most basic of all animation methods
Before write a script, you need to create keyframes first
Steps to Accomplish
Start time = 0
Interpolation = Linear
Velocity = Constant
And then click ok
Since the start is the first keyFrame, the beginning of the animation, the start time is 0. The following steps shows you how to set the start time for the remaining KeyFrames.
Start time = 10
Start time = 20
In the Animation Producer dialog, markers are placed in the timeline grid at the 0, 10, 20 seconds
In the Range section - End = 20
In the Prewiev section - Loop = Enabled
https://communities.bentley.com/products/microstation/microstation_visualization/w/microstation_visualization_wiki/25750.how-to-create-keyframes