Creating a Mask

After you have added a GMask object to the scene, you can now create the mask itself.

NoteTo create a mask using a GMask Plane node, GMask Ellipse node or GMask Rectangle node, see GMask Plane and Gmask Preset Shapes.

To create a mask:

In the Edit Modes box, select Create (N).
Do any of the following to draw the mask:
- Click to add vertices.
- Shift-click to hide vertices and tangents as you add them.
- Shift-drag to draw the mask freehand. Vertices and tangents are hidden as you add them. After closing the mask, you can use the Lasso Fit field (in the Vertices tab of the GMask menu) to increase or decrease the number of vertices that define the freehand segments of the mask.
- Click and drag out the tangents to adjust the curvature of the spline at the current vertex.
Complete the mask by closing the mask shape or leaving it as an open spline.

Editing the Mask

You can edit the mask in three ways: by gestural action, by using the Edit Box, or by modifying the settings in in the GMask tabs. Editing operations, such as adding and removing vertices, can be effected whether or not the mask is completed. You can also edit mask properties, move vertices and tangents, add and edit the gradient, track the mask, change display properties before mask completion, and make shape transformations by enabling the Edit Box button.

To add points to a mask:

In the Edit Modes box, select Add (A).
Do one of the following:
- Click on a spline between two existing vertices to add a new vertex.
- Click on the first or last point of an open mask and click where you want to add a new point to continue drawing the mask.

To delete points from the mask:

In the Edit Modes box, select Delete (D).
Click on a vertex to delete it.
If the vertex is in a mask that is a closed shape, the splines that connected it to adjacent vertices will be replaced by a single spline.

Closing the Mask

A mask can be closed gesturally or in the Mask tab.

Create the mask.
Do one of the following:
- Create a spline to connect the last point in the mask to the first point.
  The mask is completed once it is a closed shape. The Closed button is enabled.
- In the Mask tab, enable the Closed button.
  A spline connects the last point in the mask to the first point.

NoteIt is still possible to change the size of the mask by enabling the Edit Box.

Finishing the Mask

You can finish a mask without closing it to make a shape.

To finish a mask:

Create the mask. Do not close the shape.
Click the Finish button.

The mask is complete. The Finish button changes to the Edit Box button. The Edit mode changes from Create to Move.

A mask can still be adjusted after it is finished.

To adjust the mask:

Enable the Edit Box button.
Click and drag any of the points along the border of the Edit Box to adjust the mask.

You can also adjust the mask using the following keyboard shortcuts:

Press Alt to drag the Edit Box proportionately.
Use Shift to drag the opposite sides of the Edit Box proportionately.
Use Shift + Alt to drag the Edit Box proportionately from the centre.