Altering a Mask's Shape

Editing > Dissolves and Wipes > Creating Wipes > Editing Wipes >

You can manipulate points on a mask while displaying the incoming or outgoing clip.

Selecting Points

Select points using the Select option in the Edit Mode box. You can select individual points, individual tangents, or a group of points:

To select a point or tangent, click it.
To select additional points, press Shift and click the point. You can also press Shift+Ctrl and drag across a series of points.
To select multiple points, press Ctrl and drag the selection box over a series of points.

Breaking Points

You can break or modify a tangent using the Break option in the Edit Mode box:

Click a point to remove any tangents connected to that point.
Click a tangent and hold down the cursor to edit it separately from its opposite tangent. You can also select the Move option to edit the tangent without editing its continuity. Click the tangent again and hold down the cursor to edit the continuity of the tangent. Click the tangent again and hold down the cursor to edit the continuity of both tangents.
Click a point to remove any tangents connected to that point.

Calculating Tangents

Use the Auto option in the Edit Mode box to calculate the tangent for a point according to the curve the point is on. Select the Auto option and click a tangent.