I received an e-mail a few months ago from someone starting up in the industry as a roto artists asking for advice. I wrote down my go-to list of roto rules and then realised that there were a perfect 10 of them so I thought they would make a good blog post.
So here they are, my Top 10 Roto Tips:
- Break the objects down into much simpler shapes. If that means you have to roto each strand of hair separately then that’s what you will have to do. Pick one simple object and just follow it all the way through the shot, then go back and pick the next shape.
- Watch the motion of the object carefully before you start. To start with place your keyframes at the most extreme positions of the movement, then go back and refine the shapes from there. Use as few keyframes as possible.
- Use tracking data where ever you can. The point tracking in Silhouette is really good and the planar tracking in Mocha is amazing. Let these do the hard work for you and will allow you to use less keyframes.
- Try to transform your whole shape using the transform/rotate/scale tools before you start editing individual points. This will prevent boiling.
- Keep the control points of your shape on the same part of the object all of the way through the shot. If the point starts at the bottom of the guys ear make sure it stays there and doesn’t move to the top of his ear during the shot. This will cause your motion blur to be wrong and makes it harder to stop your shape boiling. If the outline of the shape changes too much to keep your shape consistent turn off your shape and start a new one.
- Keep your edge consistent. If your spline is 1px in from the edge at the beginning of the shot, that’s fine, as long as it is 1px in at the end too. The compositors can always slightly dilate or erode your matte but only if it is consistent.
- Make sure you know why the matte is needed. You can waste a lot of time if you roto areas or frames that aren’t needed.
- Learn all of the keyboard shortcuts for whichever application you are using. This will speed you up a lot.
- Keep checking your work with the solid overlay view. It is easier to see any issues this way than with your splines.
- Once you think you have finished your work check it carefully yourself before you send it to your compositor. Don’t worry if you think you are slow when you start, everyone is. Personally I think it is more important to spend a little more time on your work and get it right than try and rush it so you can send something that is wrong. In my experience people remember if they have to send someone’s work back for fixes again and again, but they won’t mind if it is a little late if they know it will be perfect when they get it.
If you liked this post check out my post on frame-by-frame painting