Brush and Smart Brush are the main tools used for outlining 3D objects.
Brush gives the option of outlining the areas of interest manually. Like Smart Brush, the software builds up each segmented image slice into a 3D object. It allows an accurate voxel-based object correction or segmentation with more restricted interpolation.
Brush is recommended for correcting structures. You can correct the structure on a slice by slice basis, which aids the interpolation process.
Selecting Smart Brush Tools