Tutorial:Blinking

Avatars may blink as a means to convey a character's personality and suggest liveliness. To blink, you must first have eyes that have been split into a separate ModelPart. Your script will scale this group to simulate blinking.

To begin with, define variables containing parameters the script will use: the path to the eye model, their height, and the length of the blinking animation.

local eyes = models.model.root.UpperBody.TheHead.Eyes
local EYE_HEIGHT = 2 --The height of your eyes in blockbench units
local BLINK_RATE = 4 * 20 -- 4 Seconds

The BLINK_RATE variable is multiplied by 20 as the script will deal in ticks, and there are 20 ticks in a second.

Next, the logic that determines when to blink will be performed in a TICK event. 4 new variables will also be needed to store the calculated position and scale for the eyes, alongside a simple timer. These will be initialized outside of the TICK event.

local oldScale = vec(1, 1, 1)
local newScale = vec(1, 1, 1)
local oldPos = vec(0, 0, 0)
local newPos = vec(0, 0, 0)

local tick = 0
function events.TICK()
  -- Sets old pos and scale for later interpolation
  oldPos = newPos
  oldScale = newScale
  tick = tick + 1

  -- If time to blink, set new position and scale to close the eyes, otherwise open them
  if tick % BLINK_RATE == 0 then
    newScale = vec(1, 0, 1)
    newPos = vec(0, EYE_HEIGHT / -2, 0)
  else
    newScale = vec(1, 1, 1)
    newPos = vec(0, 0, 0)
  end
end

In order to give the blinking a smooth appearance, the rendered position and scale will be calculated and set in a RENDER event, using the variables initialized earlier.

function events.RENDER(delta)
  -- This interpolates the blinking to make for a smooth blink
  local scale = math.lerp(oldScale, newScale, delta)
  local pos = math.lerp(oldPos, newPos, delta)

  eyes:setPos(pos):setScale(scale)
end

Here is the completed code:

local eyes = models.model.root.UpperBody.TheHead.Eyes
local EYE_HEIGHT = 2 --The height of your eyes in blockbench units
local BLINK_RATE = 4 * 20 -- 4 Seconds

local oldScale = vec(1, 1, 1)
local newScale = vec(1, 1, 1)
local oldPos = vec(0, 0, 0)
local newPos = vec(0, 0, 0)

local tick = 0
function events.TICK()
  -- Sets old pos and scale for later interpolation
  oldPos = newPos
  oldScale = newScale
  tick = tick + 1

  -- If time to blink, set new position and scale to close the eyes, otherwise open them
  if tick % BLINK_RATE == 0 then
    newScale = vec(1, 0, 1)
    newPos = vec(0, EYE_HEIGHT / -2, 0)
  else
    newScale = vec(1, 1, 1)
    newPos = vec(0, 0, 0)
  end
end

function events.RENDER(delta)
  -- This interpolates the blinking to make for a smooth blink
  local scale = math.lerp(oldScale, newScale, delta)
  local pos = math.lerp(oldPos, newPos, delta)

  eyes:setPos(pos):setScale(scale)
end