The Bouncing Ball
Utilizing the concepts of frame rate, timing, arcs, squash & stretch, volume/scale, and keyframes, create a frame by frame animation of a bouncing ball - or of a similarly boucing object. Place your bouncing ball/object in a location and try to make the ball look like it is actually boucing off of a surface.
- Start Tahoma and utilize the Startup Popup (or use Panels → Startup Popup...)
- Choose your digital practice project
- If you need a new project, select "New Project"
- If your preferred project location is not selected, choose the project location — ie. "Documents/Animations"
- Give the new project a name and press "Ok" (we will use this as a practice project for a couple animation exercises)
- Still in the Startup Popup, under "Create a New Scene", type a scene name and choose "Create Scene"

- Select
Create a background so that your bouncing ball animation can take place in a specific location. This could be anywhere from inside a spaceship to a kitchen or a park. Make sure there is some sort of rigid object for your ball to bounce off of - like a sidewalk, wall, tree or etc.
Feel free to make multiple background levels if you would like to create a better sense of space. My example actually has 4 levels, each on their own layer: sky, background, road, & grass in the foreground
- Click on the first cell of the Timeline (or the first cell of the image sequence in the Timeline) and use the Command Bar to create a new Raster level
- Give the background level a descriptive name and choose "OK"

- Right-click on the new raster cell in the Timeline and choose "Edit Cell Numbers → Timestretch" to stretch out the drawing to last for at least 50 frames

- Change the value to "50"
- In the Level Palette:
- Add a new style by clicking on the new style button

- With the new color selected, go to the Style Editor and choose a new color (click higher in the right triangle to lighten the value & reveal the rest of the color wheel if needed)
- Repeat as necessary to create your color selections
- Change the Style Editor to the "Raster" tab - there are a variety of brushes you can use here that only work on raster and smart raster levels
- To add a specific brush to one of your colors, select the color(style) first in the level palette and then click on the brush of your choice in the Style Editor (you can change brushes for a style as many times as you would like)

- From the toolbar, use the Brush tool
(B) and the Eraser tool (E)
to draw your background
- In the Tool Option Bar above the Viewer, you can change the size and opacity of the active brush - you can even use a brush as an eraser
- In the Style Editor under Settings, you can change the settings for the active brush as needed
A keyframe is a point of major transition - often the beginning and ending of an action.
Traditionally, frames inbetween keyframes were called "inbetweens". Modern animating software has abbreviated from inbetweens to "tweens".
In animations where automation is utilized, the keyframes are created by the animator while the tweens are created by the program. In cel animation, both the keyframes and the inbetweens are created by the animator.
The strength of movement and gravity both have an impact on the timing of an animation and can add to believability.
- A ball dropped from a high place will gradually accelerate due to gravity
- A ball dropped from a lower height will accellerate less
- A ball thrown with a lot of force will start out fast and slow down over time
- The same ball thrown with less force will still slow down but also will be slower overall and travel a smaller distance
- A bouncing ball gradually slows down as it reaches the apex of it's arc
- A bouncing ball speeds up as it reaches the bottom of it's arc
Before we begin drawing and animating the ball, create a guide to show where you want the ball placed as it moves through the location. Vector levels are best as guide levels as they can be easily edited. Make sure to take the concepts of timing and force into consideration when planning out your ball positions.
- With the first cell of the top layer selected, add a new vector level (or in the first cell in the next empty column of the Xsheet view)
- Give a descriptive name, ie. Bouncing Ball Guide
- Set the Step to 50

- Use either the brush or the geometric tool (set to arc) to create a path representing the planned movement of your ball
- To use the Vector Brush, press the Brush tool
in the toolbar (or use B)- In the Tool Option Bar, you may notice the brush has some different settings for vector levels
- In the Level Palette, your new vector level will have the 2 default styles (transparent and black) - not the styles/colors you made for the raster level
- Raster (MyPaint) brushes do not work for this level type so if a raster brush is active, change the raster brush to none
- You can use the "Vector Brushes" in the style editor if you would like
- Instead of creating a new style, select the black style and adjust as necessary so that the color will be visible on top of the background - you may want to lower the opacity by adjusting the alpha channel (A) but do not make the style completely transparent
- With the brush active, click and drag in the viewer to draw
- To use the Geometric Tool
, select the Geometric tool (G) then set the shape to arc

- Use the Control Point Editor
to perfect the placement of the vector shapes if necessary

- Use the geometric tool's line segments to plan out the position of your ball along the guide for each frame
or hold down on shift while drawing with the brush to make straight lines
Unless an object is rigid like wood or metal, the principle of squash and stretch often applies. Forces acting upon objects often effect the exact shape. If you sit on a cushion, the cushion sinks down a little under the weight of your body. A softer cushion will sink more. A firmer cushion will sink less. Often this can be very subtle but slightly exaggerating the effect in an animation can add realism. Be careful though - too much squash & stretch can look a little too jiggly.

Since this is a bouncy ball, it will squash as the ball hits a surface and stretch as the ball bounces away from that surface.
- Create a Smart Raster Level:
- Left-click on the first vector cell and use the new smart raster level button
(if using the Xsheet view, left-click on the first empty cell in the next empty column)
- Give a descriptive name, ie. Bouncing Ball
- Change the Step set to 1 and choose "OK"

- Draw the ball in it's first position using the standard brush (B)
- Leave the color/style set to black for now (you'll notice the new level has it's own palette)
- Raster and Vector brushes will not work for this level type - you may need to set the Raster or Vector brush to none
- Press the down arrow or right arrow key to move to the next empty frame
- Enable "Onion Skin" in order to see the previous frame (Onion Skin can also show upcoming frames)
- To set relative Onion Skin (which shifts with the active frame):
- Click straight to the left of the Onion Skin marker on each previous frame you'd like to enable Onion Skin for — previous markers display in red by default
- Click straight to the right of the Onion Skin marker on each forwards frame you'd like to enable Onion Skin for — forwards markers display in green by default
- To set fixed Onion Skin (which is always visible, no matter what frame is active):
- Click just below the top edge of the Timeline for each frame — fixed markers display in blue
- To temporarily deactive Onion Skin, right-click in the Onion Skin area and choose "Deactivate Onion Skin"
- To re-enable deactivated Onion Skin, double-click on the Onion Skin icon
- To remove Onion Skin markers:
- Left-click on a single marker to remove it
- Left-click + drag across multiple markers to remove them
- Right-click in the Onion Skin area and choose "Clear All Onion Skin Markers"
- By default, Onion Skin only works for the active layer. Only if needed, extend Onion Skin to work for the entire scene by right-clicking in the Onion Skin area and choose "Extend Onion Skin to Scene"
- To return Onion Skin to only working on the active level choose "Limit Onion Skin to Level"
- Make sure you have the 2nd cell for your ball level selected/active in the Xsheet/Timeline then draw your ball in the second position
- Use the down or right arrow to move to the next empty frame and continue the process until you have drawn the ball in each desired position (don't forget to use arcs, squash & stretch and etc.)
- After the ball has been drawn in for each spot in the guide, select the entire ball column/layer and set each drawing to display twice:
- Click on the layer icon
- or click on the top edge of the layer (left edge of a column)
- Set the step to 2
- Click on "2's" in the Xsheet Toolbar/Command Bar

- Or right-click on the selected column/layer

The term cel-shading comes from the celuloid process when colors were painted by hand. Instead of creating full gradients from light to dark to show shading, artists would use a limited number of colors to save time. When an object or character has cel shading, traditionally there is a highlight and a shadow color added to a basic fill color.
- Create 3 new colors/styles for your ball's Smart Raster level:
- A midtone color (your choice)
- A temporary shadow color (typically blue)
- A temporary highlight color (typically red)
- With the highlight color selected, use the brush to draw the edge of your highlight (with the first cell active)
- The highlight may be a separate closed shape that doesn't necessarily touch any other lines

- The highlight may be a single line that creates a closed shape with other lines

- Repeat for the rest of the frames - use the down or right arrow key to move down the Timeline
- With both the first cell and the shadow color selected, draw the edge of the ball's shadow for the first frame (make sure this makes a closed shape for the shadow)

- Use the paint bucket
(F) to fill in the colors for each frame (should be set to "Areas")
- Go through each frame and fill the hightlight color
- Go through each frame and fill in the shadow color for each frame
- Go through each frame and fill in the midtone color for each frame
- Trying to fill a shape that is not closed may result in the color filling a larger area than expected
- Set the shadow and highlight styles to lighter and darker values of your midtone color
- Click on the highlight color in the Level Palette)
- In the Style Editor, select the color you want to use for the highlight (as long as Auto-Apply is on, the color should automatically update)
- Select the shadow color in the Level Palette and use the Style Editor to change the color

Create a frame by frame animation of a bouncing ball that includes the following:
- A background/sense of setting
- Timing (acceleration and/or deceleration)
- Force (changes in speed due to strength of initial movement and gravity)
- Arcs
- Squash & Stretch
- Cel shading