Visual Object Tracking (VOT) is usually relegated to bounding boxes, because they're less time consuming to make. Darwin allows you to create instance mask object tracking in a quick and easy way.
You can activate Instance IDs by heading to the Classes tab in your dataset, editing or creating one, and adding Instance ID as a Subtype.
Once you create a class with an instance ID you can edit it by accessing the object centroid and pressing the ID icon. Here, you can type any value you wish.
Each value up to 999 billion is represented with a unique set of colors that will assist you in comparing and matching instances once datasets start becoming large.
When moving between frames of a video, you can copy over objects and their sub-annotations, such as instance Tracking IDs using the "Copy Annotations" button, which will carry over the previous frame's object in bulk, or by copying and pasting them individually.
You can also paste sub-annotations using the CTRL + Shift + V shortcut (CMD + Shift + V on Mac). This will only paste sub-annotations, such as Instance IDs or attributes, and not the annotation itself.
After copying over an annotation to a future frame, you can adjust it to the new position and shape of the target object by re-running Auto-Annotate. The shortcut for this is M.