… for Apple Motion

Tip #1317: An Example of a B-spline Mask

Larry Jordan – LarryJordan.com

The B-spline mask tool is great when you DON’T want sharp edges.

Most of the time, when we need a mask, we’ll use the Bezier tool, because it creates very flexible, highly-precise masks. So, I wondered, when should we use the B-spline mask tool?

The B-spline tool creates “blobs,” masks which have no sharp edges. It reminded me of the Blob generator in Final Cut.

So, I set out to create my own blob and discovered the very interesting effect you see in the screen shot.

Process:

• Add Chalk 03 to a layer
• Apply Behaviors > Spin to rotate slowly
• Apply Filters > Blur > Gaussian Blur
• Manually enter an Amount of 700, to make it REALLY blurry
  –
• Add Chalk 02 on a higher layer
• Apply Filters > Blur > Gaussian Blur
• Manually enter an Amount of 700
• Use the B-spline mask tool to create a blob of this upper layer, then add as much feathering as possible
  –
• Finally, add keyframes to different B-spline control points so that the shape of the blob animates/morphs over time

Cool.

EXTRA CREDIT

There’s lots of other effects you can add to change the look of this effect. Feel free to play as much as you want.