This unhelpful error message occurs when the traced lengths exceeded the maximum permitted, usually due to the program not correctly finding the end of the root.
Replacaced with a more helpful error message.
Replaced with better error message.
Underlying cause (length>max permitted) still possible, but should be possible to fix by choosing good background model and tracking model.
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Replaced with better error message.
Underlying cause (length>max permitted) still possible, but should be possible to fix by choosing good background model and tracking model.
May be caused when root grows near/off the edge of the image, and blender bar >0 used as motion model
Additionally, having overlapping roots can cause this.