Hi @akar.zaephyr ,

I was a little confused by the interpAccel parameters as well. Here is a post from @lucky.andrei

that pretty well breaks it down.

Here is a breakdown of the expression and its elements:

`interpAccel(Time format, Min, Max, Acceleration Factor)`

**Time Format** = this can be any time related tag. Generally #DWE# is easiest to start with since it is a simple running time that starts when you wake your watch.

**Min** = Start point in the Time Format you chose above

**Max** = End point in the Time Format you chose above

**Acceleration Factor** = Speed at which the interval accelerates

From this I had a few questions in trying to implement this expression. The difficulty is understanding that you need to have a start and end point. This is different from the expression above. The full formula is really:

`(x+(interpAccel(Time format, Min, Max, Acceleration Factor)*y))`

x = starting point

y = end point

For instance, here are three variables on an element that you can use:

**Position** (i.e. x and y axis)

Placing this expression in the x axis will move an element

- Animation will begin at ‘0’ seconds of #DWE# (wake)
- Element moves from x-axis position of 0 to 160
- Animation will end at position 160 over the course of 2 seconds

`(0+(interpAccel(#DWE#, 0, 2, 1.5)*160))`

**Rotation**

@Tomas has a great tutorial on this example posted HERE:

- Animation will begin at ‘0.2’ seconds of #DWE# (wake)
- element from position 0 to #DWFSS# (i.e. current seconds position)
- Animation will end at position #DWFSS# over the course of 0.6 seconds

`(interpAccel (#DWE#,0,2,0.8) * #DWFSS#))`

**Size**

Placing this expression in the Size variable (Height, Width, Radius) will increase/decrease its size:

- Animation will begin at ‘4’ seconds of #DWE# (wake)
- Element will start at size 0
- Size will increase to 8 over the course of 2 seconds

`(0+(interpAccel(#DWE#, 4, 6, 2)*8))`

The last mysterious piece of the expression is the acceleration factor. My best guess to how this works is in the diagram below:

Decreasing the number to 0 will smooth the animation. Increasing it appears to give a ‘ramp up’ in the observed animation.

[Mini-Tutorial] InterpAccel - Fly In Motion Expression Help

This bit is key to what you are trying to accomplish.

`(x+(interpAccel(Time format, Min, Max, Acceleration Factor)*y))`

x = starting point

y = end point

Good luck bro!