Rotobrush 2 help

[Mistano]

Hello there, i’m lookin for a feature with rotobrush 2, i need to back propagate my analyse, but i couldn’t find how to do it, as i must change some details in the middle of the footage, to get the bad analyse good.

Can you help me please ?

Thanks a lot !

[Tim Kurkoski]

To propagate Roto Brush backwards from the current frame, you need to go frame-by-frame by using the keyboard shortcut for previous frame, Page Up, or use the Previous Frame button in the Preview panel.

[Mistano]

hello, when i try to do this, the propagation isn't propaged backwards from a modified frame, how shall i do it ?

Thanks a lot !

[Tim Kurkoski · Accepted solution]

On the frame you're adding new strokes, is the existing propagation going forward or backwards? You can tell the difference by the direction of the green arrows in the Roto Brush propagation span bar, below the time ruler in the Layer panel.

This is important, because if you add strokes, they will only propagate forwards OR backwards, depending on which direction the propagation is already going. Propagation only works in one direction at a time from the base frame (the first frame you draw strokes on, represented by the green rectangle with the dot in the middle).

If you need to change the Roto Brush propagation in both directions from a given frame, you should create a new span. Drag the one of the blue end points of the existing span to the end of where the existing propagation is OK, then move the CTI to the frame where you want to create the new base frame for propagation and draw new Roto Brush strokes. Then propagate the new span backwards and/or forwards as necessary.