how to know when an Null object accelerates or brakes?

Scripting for After Effects

how to know when an Null object accelerates or brakes?

Postby Mathieu Thibaut on 03/12/2017, 3:59 pm

Hello,

I have a very simple set: a null object that moves around. the trajectory is made by hand, (but I guess it could also be from a wiggle expression).
This null object is leading the emitter in particular, and I would like to be able to produce particles only when the Null brakes (slows down suddenly) or when it accelerate.

Is there any expression to detect when an object brakes or accelerates?

thanks

M
Mathieu Thibaut
 
Posts: 1
Joined: 03/12/2017, 3:40 pm
System Specs: windows 8, ram 12gb, nvidia graphic card

Re: how to know when an Null object accelerates or brakes?

Postby Mylenium on 03/14/2017, 8:04 am

You need to integrate the velocity at any given time and compare it to a previous state and then define a threshold. Refer to this for basic concepts:

http://www.motionscript.com/articles/speed-control.html

Mylenium
[Pour Mylène, ange sur terre]
----------------------------------------
www.myleniumblog.com
Mylenium
 
Posts: 3263
Joined: 02/1/2009, 11:45 am
Location: Germany
System Specs: Have, I do!

Re: how to know when an Null object accelerates or brakes?

Postby vjk_vfx on 05/13/2017, 1:21 am

plz check this script if it's helpfull
Attachments
2.png
vjk_vfx
 
Posts: 15
Joined: 05/2/2016, 11:57 pm
System Specs: i3, gigabytes
8gb ram
500 hdd


Return to After Effects Expressions