Rotoscoping

In order to combine any pieces of imagery/footage within visual editing software, the process of ‘Rotoscoping’ takes place. Rotoscoping involves the tracing of an object in order to create a silhouette/matte that then extracts the object from a scene therefore enables the placement of another background.

To do so,  the following steps need must take place:

Upon opening the read file (R) which needs to be extracted a rotopaint node needs to be added.  However before doing so, the read file needs to be attached to the viewer. Followed by the rotopaint node.  The brezier then needs to be used to trace the outer area of the object, creating an alpha channel in which makes the selected areas white and outer areas black. This will then need to be key frames throughout the shot as the object moves.

Following this process, a premult is needed in order to extract the white selected areas and remove the black, similar to that of the green screening process.

Add the second set of footage, followed by a merge node in order to view the two sets of footage combined with the rotoscope which will then also be attached to the viewer.

After this, if needed: create the transform/grade nodes in order to edit scale, placement or gradient.

The nodes should look like this: