Rotoscoping - Separating elements from a shot by tracing around them, essentially.
First of all I added a 'grade' node to the original footage to adjust the white/black levels. This made the footage have more contrast, and therefore made it easier to track.
A 'Roto' node was the added (shortcut key 'O' in the node graph). using the bezier tools I then divided the rabbit up into sections as seen in the 'roto' node's layer panel (fig.5). Starting from some key positions in the footage where the rabbit is most exposed, I used the bezier tool to trace around the separate limbs. This was made easier by adjusting the opacity of the roto-shapes so i could see through to the background plate (fig.1)
Roto shapes have the ability to feather using small handles on each bezier point. The feather is indicated by the dotted line, the shape by the solid line (fig.2).
Once one frame is done, you move to the next significant frame and transform the shapes to once again fit the subject you are tracing (fig.3). The software will automatically key the frames where alterations were made, key frames are shown in blue on the timeline (fig.7).
Nuke will also tween from key-frame to key-frame.
The process of moving the shapes to fit each frame continues until you have a complete rotoscope.
The final result will be a moving silhouette of the object/creature you traced (fig.4 shows the resultant Alpha).
The node graph is shown in fig.6.
No comments:
Post a Comment