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you can fly!?Project Dogwaffle - PD Pro Post Work Tutorial #2

Using the Timeline Editor for Special FX.
(best viewed with 1024x768 or higher screen resolution - it's the 21st century, and you'll need this for Project Dogwaffle anyway.)


As a reminder, the original clip is courtesy of and copyright by :
Jack Whitney Studio
Digital Illustration, Animation & Design


1 -  Timeline Editor Basics

  Before starting with this tutorial, be sure to load the AVI file named  "theCave.avi" as created in the prior tutorial.

Now you're ready to start. Open the Timeline editor from the Animation menu:

Animation > Timeline...

What is the timeline editor?  You are sure familiar with the concept of filters, that apply special effects (fx) like gaussian blur or sharpening, color changes and miscellaneous transforms such as spherize. Such filters (found in the Filter menu) usually apply themselves on a simple image, i,.e. the current image buffer, or the current frame alone (when there's an image sequence or animation).

By contrast, the Timeline editor allows you to apply its filters over all frames of the animation. Furthermore, you can see the parameters of the selected filter and modify them to change across the timeline. This is done simply through keyframing on desired frames along the timeline. Dogwaffle will then interpolate between the keyframes, in linear or Spline based interpolations.

It is easily possible for example to use this with a brightness filter and cause the brightness to change, for instance from frame 0 to 20. Bringing the brightness from dark (black) to 100% in this manner will make an effect like 'fade from black'.

  There are many types of filters in the timeline editor tool. The one we're looking for at this time should simulate bubbles of air rising from the ocean floor and up in the water.

Unfortunately, there is no such filter in the Timeline. But, there is one that will be useful instead: the Snowfall filter. Of course, the snowflakes fall downwards, whereas we want the bubbles to rise. So, we'll just have to pretend we're in Alice Springs, and think like down-under - Flip the whole movie up-side down, then apply the filter of Snowfall, then flip the filter right-side uip again.

Thus, go to the Buffer menu and select Flip/vertical:

Buffer > Flip > Vertical

PD Pro immediately flips the current frame upside-down. Then it asks if you want to apply the flip to all frames of the animation (insted of just this one).

Click Ok and the whole movie will be upside-down.
Now, look for the Snowfall filter in the Timeline editor along the left side of its control panel.

The Snowfall filter is near the bottom of the set in the Animated category. These filters are animated even if none of their parameters are changed across keyframes.  (there are a few more such filters, such as the wave distortion fx in the Transform category)

When you select the Snowfall filter, you'll see several sliders indicating the filter's parameters:

  • Snowfall (amount, or density of snowflakes)
  • Velocity (of flakes falling down, or drops if going fast)
  • Wind speed (to the left or right)
  • Turbulence
  • Size of flakes

Select your preferred parameters, or just experiment with the default settings.

Then select the "Render" button in the lower left of the Timeline editor.

This will run the filter across all frames of the animation.

A progress bar  will show which frame it's working on. You can stop the rendering if you need to.

You can also click the Undo button. This lets you restore one level of rendering.

Rendered frames are stored in a Temp folder. If you work on large images and thousands of frames, perhaps you don't want to use the disk space for this. You can optionally uncheck the "Save undos" checkbox. Just be aware then that you can't go back to the prior movie with "Undo" in that case. Save often. Saving to native animation format may be the fastest way. It's not compressed, so you won't have to go through a codec selection dialog.

2 - The Linear Alpha Fader

It would be cool if we could make it look like some of the bubbles are not immediately visible when over or near the ground. They could appear to grow in size or fade from small to large size by making them fade in to full visibility.

One way to achieve such an effect is to use a linear alpha mask. At or near the ground of the ocean floor, the alpha will be off. Then it becomes more transparent (write-enabled) as it gets closer to the center and goes past the top of the cave.

This can be achived with the Linear Alpha fader.

Right-click the Linear tool in the Tools panel...
The menu of the Linear tool shows several linear and curvi-linear/circular tools and variants thereof. Many things can be constructed with the basic help of a rubberband line or circle as a constructing shape.

One of them is the Linear alpha fader. Choose that one.

The linear alpha fader starts from a fully write-enabled (transparent) mode and, as its name implies, fades away to fully blocked, opaque alpha.

Of course, the top of the cave is still near the bottom of the inverted (flipped) image.
To begin setting the linear alpha fader, click-and-hold somewhere in the image at a place which you still want to leave write-enabled. (transparent alpha)

Move (drag) the cursor, with the button still pressed down. The rubberband line indicates the direction along which the alpha will  change from transparent to opaque.

When you release the button, the endpoint of the rubberband line indicates the area where the alpha has completely become opaque (blocking).
The alpha transition is shown in the form of a line that's perpendicular to your rubberband progression line, and which indicates the middle (50% alpha) of the progression.

You can thus use this tool to make alpha faders in which the alpha changes very abruptly (short rubberband line) or over a long distance.
You can also keep adding additional alpha faders to the current one.

The linear alpha faders are multiplicative to the current alpha mask and eat away or add to it depending on where you place them and where they're already present.
To see the effect of the linear alpha fader, or any alpha maskfor that matter, choose any filter with a good visual effect. For exmaple, if using the Snowfall filter, set the size fairly high (not too high, it can take a while to render if you have much snowfall and a slow computer).

The preview window in the upper-left of the Timeline editor will them show the Snowfall only through the enabled portions of the alpha mask. (lots of white fluff and stuff near the lower left of the preview in this example)

If you need to do anything with the Alpha channel, such as storing a safe copy of it temporarily away, or bluring it, and many other things, look for that in the ALpha menu.

To clear the alpha channel's buffer altogether use the first menu item or the Control-D shortcut.

3 - More Alpha Selection Masks
Now that the alpha mask is in place, select some parameters as shown here for the Snowfall effect:
- lots of snowfall
- little velocity
- minimal if any wind speed
- default (low) turbulence
- small size

Render this filter across the timeline, and you will end up seeing snow flakes which are not immediately visible near the top of the image (which contains the ocean floor). The then gradually become visible and are fully present around the middle of the frame, or wherever you started the linear alpha transition.
There are other ways to select the desired local area of interest. For example, if you had a treasure chest partly stuck in the sand on the floor, you could want to have a few isolated bubbles emerge out of the treasure chest.

You could use the "Lasso to alpha" tool to select a vertical shape that will permit bubbles (snowflakes) to appear therein.
In another example, the lasso tool could be used to select an area around the swimming sea dog between the cave and the side where it leaves the scene.

That selection mask could then be used to confine something like a motion blur effect to that water 'canal'.
In some cases, further fine tuning of the selection mask is desired.

There are several ways to paint directly on the alpha mask. Right-click on the Tool panel's brush icon, and select "Paint on Alpha>"

In this example, the "Blobby 50" mode was used to paint the selection directly onto the buffer's alpha channel.

Typically you will want to also blur the alpha. This can be done from the Alpha>Blur alpha... menu

Like mentioned earlier, it is possible to take a snapshot of the alpha channel from the Alpha menu, through this option:

 Alpha > Store alpha...

It is possible to do a variety of things to the image mask of the alpha buffer. You can even paint directly on it there too.

This concludes this portion of the tutorials. You can now create various selection masks of varying  degrees of complexity to prevent or allow filters from the Timeline editor to be applied in controlled regions.

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> back to tutorial #1
> this was tutorial #2
> advance to tutorial #3

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