Before I post some examples, what version of SolidWorks are you using currently?
Try creating a billiard ball and post your attempt here.
I would imagine that the SW help explains it adequately. Split line is very useful in machine and consumer modeling when one needs to introduce new topology (for instance -geometrical edge) into the model. For instance. You extrude a block of material but it will become a injection molded part to be molded with a non-planar (curved) parting line. Before the part line draft is attempted, the use will create a Split Line using a sketch which is then projected on the 4 side faces of the block. At that point the part line draft feature has the lines ( new topological edges in the block) to create the part line draft drafted away from each side of the edge in the block.
the examples on youtub seem to conflict in what theyre saying ie mixed with split ,where a wing is cut into 2 parts and saved and others differ.
i can make a disk cut it into sections with split lines and color the sections with different colors .
but thats different than using split which carves up a solid part and then ditches the cut away section.
theres a split
and a split ine in curves and a split line in features
3 options of split
i will put this on the back burner and return at a later time
I think you are confusing the Insert>Feature>Split with
these are two very different things.
I can post a exmple that demonstrates both in the same file, but you didn't answer my question.
The split part command ( menu>insert>features>split ) is used to split solid bodies into two or more parts were as the split Line ( menu>insert>curve) is used to split model faces.