Smash directional influence

Smash DI, or SDI, is a mechanic, like directional influence, that is performed during the frames of hitlag in which the target is immobile after being hit by a hitbox. The length of the hitlag varies from attack to attack, from 2 frames to 18 frames (Samus' Charge Shot). Smash DI allows the character to shift their position before being launched, which primarily allows players to escape multihit moves and certain combos, but can also slightly increase a character's endurance (by shifting their position from a blast line slightly farther away before launching), and can move the character into a wall or ceiling to allow wall and ceiling techs. By pressing different directions on the control stick, the player can Smash DI multiple times. This is best represented in the Perfect Control video, at approximately 2:38, and with a frame-by-frame version at about 3:51, during the end credits.

To perform SDI, a player has to move the control stick or c-stick during the hitlag of a move. Whatever direction they input, the character will shift a very slight distance in. Using both the control stick and c-stick together when SDIing, known as double sticking, can allow a player to make more SDI inputs than what would normally be humanly possible.

A subtactic is the quarter-circle DI, which involves inputting multiple SDI inputs more easily by rotating the control stick 90 degrees. Quarter-circle DI was introduced to the United States by smasher Captain Jack and was once known as Japanese DI.

Despite its near identical name, Smash DI is not a subtype of directional influence, but a different mechanic altogether that is performable under the same circumstances. The major difference being that, while DI changes the trajectory a character is launched in, SDI changes a character's position before launch.

Unlike DI, SDI is possible in the original Super Smash Bros..

Automatic Smash DI

Automatic Smash DI functions similarly to Smash DI, but it occurs the frame after the attack's hitlag ends. The character will move, but not as far as in normal Smash DI. ASDI may be inputted either with the control stick or the C-stick, but if both are being held when hitlag ends, the direction in which the C-stick is being held out prioritizes the Control Stick.