Slide-based tours have only a start and end position and WWT smoothly moves between them. However, if you need finer control to change views, location and appearance of objects etc. in a more flexible fashion. Each slide of a tour can have timeline control.
Important: Tours containing timelines can only be played back on WWT 5.0 or later. When you first add a timeline you will see a warning to this effect.
To create a tour using timelines, do the following:
- Create a new tour - "Guided Tours/Create a New Tour..."
- Set Look At mode and orient initial view for the Tour.
- Create an initial slide by clicking "Add New Slide"
- Right-click on this slide and select "Show Timeline." This will display a timeline window at the bottom of screen. The buttons outlined allow you to adjust the size of the window as well as unpin it from the main window.
The timeline editor shows objects and settings on the left. Initially, there will be a single element on the left called "Camera." The "+" symbol to the left will open a list of attribute you can control. There are transport controls which take you to the beginning or end of the timeline as well as playing forward or backward. The time is shown across the top of the remainder of the frame. Time is shown in MM:SS along with frame numbers – 30 frames per second. Objects can be controlled down to 1/30 of a second. You can use the scroll wheel on your mouse to change the scale of the timeline if the mouse is over the numeric labels and to scroll the view of the timeline left and right if the mouse is below them in the timeline. You can grab yellow triangle which adjusts the current time. This is useful to get from one point to another and see motion in the main window.
Note: The one aspect of the view that cannot currently be controlled by the timeline is the Look At mode. This must be set once for the entire slide.
Note: If you change the duration of a slide with an existing timeline, it will ask you if you want to trim/extend or scale the timeline.
For this example I will Look At SolarSystem. A one-slide tour showing this example is available here.
Adding Objects: You can right click and select “Add to Timeline” on many of the objects in the Layer Control Manager on the left hand side of the screen. For some planetarium productions, the constellations need to be turned on at some point and then fade out. You can add separately control Constellation Pictures, Figures, Boundaries and Names. In this example, I will add Constellation Figures. I will also add “Planetary Orbits” under “3d Solar System,” which shows up as “SolarSystemOrbits” in the timeline editor.
You can also add an overlay objects that are created by clicking the Text, Shapes or Picture buttons in the upper left of the WWT window. Create the object such as a text object and then right click it in the main window and select “Add to Timeline.” For this example, I’ll create two Text Objects called “Our Solar System” and “The Sky” and put them at the same location. Then add them to the timeline.
Hint: Sometimes you can’t see the overlay objects because then are stacked up, underneath a menu or difficult to find in Full Dome mode. In the “Guided Tours” menu select “Show Overlay List.” A list of text, shape and image overlays is shown. You can right click on overlay objects and change the ordering, color etc. You can change the name in the Overlay List by right clicking and selecting “Properties.” When using the timeline editor do not select Animation, which a slide-based way of doing the same thing as timeline editing.
Keyframes: Each object or setting in the timeline can change display attributes at specific times and WWT will smoothly move between them. These are called Keyframes and are represented in the timeline editor as light rectangles. Above the list, there is button to create (key) and delete (key with x over it) keyframes. Initially, there is a keyframe at the begging of the timeline for every object.
In this example, I will start with a view of the sky with constellations, fade out the constellations and fade in planet orbits and end with a view of the Solar System. You can easily move keyframes in time, so start by considering the sequence and refine the timing later.
I will start by expanding the timeline editor clicking the up arrow. I will first adjust the constellation figures to fade out from second 4 to second 5.
- Click the “+” symbol to the left of “ConstellationFigures.”
- Click on “Opacity” under “ConstellationFigures.”
- Move the timeline scrubber to 00:04.
- Click the Add Key button (looks like a key above the list).
- Move the time to 00:05.
- Make sure “Opacity” is still highlighted and click Add Key button.
- Click on the first key you made at 4 seconds. An editor box will show up. If a single key is selected then the label of the key will be shown above the field on the upper right. If key object is not expanded a keyframe will control all attributes. Note, the time field is also shown but you cannot
change the time.
- Make sure the Opacity is set to 1.
- Edit the Opacity keyframe at time 00:05, and set it 0. Then close the window by typing the X in the upper right.
- Do the same for the Opacity keyframe at time 00:00.
- Edit the Opacity keyframe at time 00:05, and check that it 1.
- Do the same (steps 1-11) for the “Color.Alpha” attribute under the Text object entitled “The Sky.”
- Run the time scrubber back and forth and you should see that at time 00:04-00:05 the constellations and text “The Sky” will fade out.
- For the “SolarSystemOrbits” create keyframes at 00:04 and 00:05 the Opacity attributes to 0 at time 00:00 and time 00:04 and to 1 at 00:05.
- Repeat this for “Color.Alpha” for the text object “Our Solar System.”
Now when you play the tour (either with the play button in the timeline editor or the big play button to the left of the single slide of the tour, the tour plays, showing the sky rotating with constellation figures and text label “The Sky” shown. Then at 00:04-00:05 these elements fade out and the planetary orbits fade in with a text label “Our Solar System.”
Advanced: Keyframe editor can also allow you to select “Transition Functions.” These affect the way attributed change between one keyframe and another. The transition of input and output values is shown graphically. You can select from the following choices.
- Linear — Numbers are linear changes between values
- Exponential — Changes are change faster at the begging and slow down at the end – similar to EaseIn below.
- EaseIn — Changes are change rapidly at the begging and slowly at the end.
- EaseOut — Changes are change slower at the begging and rapidly up at the end.
- EaseInOut — Changes slowly at beginning, changes rapidly in the middle and slowly at the end.
- Instant — Keeps starting value until the very end where it changes instantly to a new value.
- Custom — Allows you to change the curve interactively. Grab the yellow square handle on each end of the curve which manipulates the beginning and ending shape of the transition curve.
It is good to choose a keyframe such as camera motion and try out all the transition functions to get a sense of what they can do.