Parent / Child Hierarchy
In Animation, the concept of the Parent / Child Hierarchy could be explained as such:
A finger is a part of a hand, which is attached to a wrist, which is attached to a forearm, and so on. Ergo, when we wave an arm, the finger as a result of its connection to the hand, etc, is also animated with the rest of the arm, wrist and hand.
Another way to look at this is with a simple list breakdown.
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SHOULDER (Parent)
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BICEPT
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FOREARM
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WRIST
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HAND
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FINGER
Everything beneath the shoulder is a Child to the Parent (the shoulder). Wherever the shoulder goes, the children will be attached. This is an important concept to understand when setting up a rig for Animation.
By default, new Objects created in a scene will not be tied to one another. You must manually set the Parent / Child Hierarchy before you begin Animating. This is done via the Explorer Menu. We will cover this in the next module.
Time-line & Playback Menu
The Time-line and Playback Menus are pretty straightforward. If you hover your mouse over any of the buttons, a pop-up will indicate what the tool does (as in all menus in XSI).
The Time-line is broken down into 100 frames by default, 24 frames equals 1 second. You can raise the time-line value to whatever you like. Once you have setup an animation, you will be able to Scrub an animation by dragging your mouse left and right over the time-line.
As well, the Playback Menu is the control panel in which to view your animation. Stop, play, forward, backwards, etc.
SETTING KEYS
Locate the Animation Tools Menu on the bottom right.
This menu is very intuitive and is the fastest way to start animating an object. We will review the most commonly used features it contains in the next module.
By setting a Key, we are referring to the process of f lagging a specific frame in the time-line. Whatever is setup in your scene, will be tied to that Frame, known as a Key (i.e. key frame). The animation program will extrapolate the data in between 2 Keys, so the animation is smooth from one Key to the Next.
For Example:
If we create a sphere on the floor, and set a Key for this state at frame 1, this will be the state the sphere starts in at the beginning of the animation.
If we then move the sphere upwards, followed by setting a new key at say Frame 10,
XSI will translate all of the sphere’s positions between frame 1 and 10 – frames that we did not set keys in will be automatically populated for us. Of course we can go back after, and edit the automated animation between Keys… But more on that later.
Note: To begin setting keys, an object must be selected in Object Mode, in addition to being in Transform mode (otherwise, how are you going to animate a static object?)
AUTOKEYS
Auto keying is nearly identical to manually entering Keys. The only difference of course is the Auto feature. This is great for a variety of reasons, but it must be used with caution, and should be toggled off frequently, otherwise adjustments you make, but didn’t intend to animate, will plague your animation time-line.
Auto keying is great for basic translations, and entering values into the Transform menus. Quick and dirty is the name of the game. For precision animating, you will want to turn this off, and manually set your Keys.
Exercise 1:
By using Auto key; Practice animating a sphere by entering numeric values in the Transform Menu. Set your time-line for 60 frames.
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Create a sphere, enable shading in the camera view, and set its radius to 1.
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Translate the sphere to the far left of your grid so we have room to animate to the right.
X = -18
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Turn snapping ON and move the sphere so that it sits on top of the grid.
Y= 1
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Press the Auto button underneath the Animation Header menu in the bottom Animation shelf (it will turn red indicating its active).
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Under the Transform menu highlight the -18 value in the X axis and manually type in the same value of -18 and press enter.
Note: By doing this, with the Auto key feature enabled we are setting the Initial state of the sphere (X = -18) at Key Frame 1. Without setting our starting frame, our animation will not work as expected later.
You will also notice that there is now a red box under Frame 1 in the Time-line menu, indicating we have set a frame:
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Now move the red Time-line marker to Frame 10.
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Enter the following values into the SRT Text boxes under the Transform Menu.
X = -16, Y = 4
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Move the Time-line marker to Frame 20
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Enter the following values into the SRT Text boxes under the Transform Menu.
X = -14, Y = 1
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Press the | < Button to return to the first frame in the Time-line, and press > to Play this animation.
The Sphere does a simple bounce!
Hover your mouse over all of the playback control buttons for a description of what each does and experiment with them on your animation. For example the far left buttons in the playback menu will cycle through each frame of your animation (Previous Frame | Left, Next Frame | Right). This is a handy way to see the frames that XSI sets up for you in between your key frames.
You can also observe this by manually dragging the Red Time-line Marker left to right, etc. This is called scrubbing.
Note: If you want to adjust any frame in between key frames we already setup, simply drag the time-line marker to the desired frame and make your adjustment. Since Auto key is still enabled, your changes will automatically be key framed.
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Continue animating the sphere across your scene, from left to right. Simply add the value (+2) to the X axis and alternate between 4 & 1 for the Y axis to simulate the up and down of the bounce every 10 frames.
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At frame 60 the SRT Text box values should be:
X = -6, Y = 1
Note: If time permits go ahead and set the time-line to 120 and continue animating the ball across the screen.
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Feel free to save your work in the Scenes Directory under Haus of Mapping Curriculum Project Path.
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