Cast animation/Cast backswing

The part of the animation which occurs after cast point has been reached is called backswing animation, and during it the unit is unable to attack or use abilities. This part of the animation is purely a liability; it has no effects besides temporarily impeding the unit, and as such it is beneficial to cancel a long backswing animation, which will allow the unit to execute other commands sooner. The player can cancel the backswing by ordering the unit to stop, move or simply by using an item or casting another spell during the backswing. Disables, including silence, will cancel it as well. However, queued orders do not cancel it. If orders are queued, the next order will be executed after the backswing finishes.

Backswing is individual to units and their abilities, and is not necessarily the same length even for spells with the same total animation time. For example if the entire animation of a spell takes 1 second, and the spell's cast point is at 0.3, the backswing will take 0.7 seconds. However, a spell animation of the same length with a 0.6 cast point would only have 0.4 backswing. Some units (and/or specific abilities) have long backswing animations, and it is on these units that cancellation of backswing will be most beneficial. Cancelling a short backswing is difficult, and generally achieves minimal difference in outcome, so it is not generally done.

As mentioned earlier, animations are bound to a unit's ability slots, whereas cast points are bound to the specific spells. As an example, uses the same visual animation (which has a length of 1.1 seconds) for all spells he gains through, meaning that irrespective of the brevity of the devoured unit's animation, when Doom performs the ability the animation will take 1.1 seconds - his animation time for that slot. This means if he were to use the ability (which has a cast point of 0.5) from the Harpy Stormcrafter, the cast backswing necessarily takes 0.6 seconds, to conform to Doom's 1.1 second total animation, even though when performed by the Harpy itself the ability has a different backswing time. If steals the Chain Lightning spell from Doom with  and then casts it, the animation will become the animation for Rubick's ability slot, and consequently the backswing would be 1.07.

This goes for every animation and ability. But since Ability Draft is the only game mode where abilities can have a different slot or be on different heroes, this only matters in that game mode. In all other game modes, it only matters for Doom and Rubick, since they presently are the only heroes which can acquire spells of other units.

Ignoring backswing
Just like how there are spells with no cast point, there are also many spells with no cast backswing. This means, once the spell reached its cast point, the unit will not pause, but will directly continue with the next order if given or queued.

Most spells which ignore the backswing have it directly set in the ability; there is no rule for which spells ignore it and which don't. However, all spells which do not interrupt channeling spells upon cast will ignore the cast backswing. Some abilities do not directly ignore the backswing animation, but rather leave the unit no other choice than to skip it. These abilities usually force an order on the unit as a part of the spells effect, such as ordering Juggernaut to attack the target or the Spirit Bear's  ordering the bear to stop.

No toggle or channel abilities have a backswing.

Abilities with no backswing
There are 5 ways a spell can have an instant cast backswing:
 * It has the "DOTA_ABILITY_BEHAVIOR_IGNORE_BACKSWING" tag, which causes the spell to ignore the backswing animation. It causes the visual animation to instantly stop once the cast point is reached.
 * It has the "DOTA_ABILITY_BEHAVIOR_IMMEDIATE" tag, which causes the spell to neither use cast point, nor cast backswing.
 * It has the "DOTA_ABILITY_BEHAVIOR_TOGGLE" tag, which turns the ability toggle-able, meaning it neither uses cast point nor backswing either.
 * Its backswing gets interrupted by forced orders issued by the cast spell, or is a channeling or transforming spell.
 * In some rare cases, the used animation is simply too short to have any backswing animation.

Анимация применения/Остаточная анимация 施法动作/施法后摇