Maya

How to fade particle instancer

(Maya Dynamics Tutorial)

In this tutorial i`ll try to explain how to fade particle instancer on

a particle basis :). So, here we go :

I`ll duplicate my object which i intend to use as instance 10 times for this example.

The number of duplicates are actually steps of fading.

After fhat i`ll duplicate the shader of my object 10 time as well and I`ll lower the transparency on every shader 10% lower then the previus one. After that assign

the shaders to my object like in the screenshot below.

II`ll create my particle object and i`ll prepare it for instancer. Having to make those basics/routine every time i`m using MEL snipets to add custom attrs and write some basic creation and runtime expresion. So here is the code, just select your particle shape and run it.

Now i`ll open creation expression and replace the row which

set te x_indexPP attribute with x_indexPP = 0;

Now i`ll select my 10 objects and attach the instancer. (make sure the instacer attr are set like in the screenshot so the custom attr will be used);

If I hit play i`ll get something like this (i`ve keyed emmiter emission rate at frame 0 with

value 20 and at frame 20 with value 0, just to keep the scene readable) :

Now I`ll make two new custom attrs, named x_dieAt and x_dieAtPP. x_dieAt is a %

value of the lifespanPP at which i want my particle to start fading. x_dieAtPP is the

calculated value at which my each particle i want t start fade, and i`m using it

because i have diferent lifespanPP for every particle. Next, in the creation expression

i`ll add the line which calculate x_dieAtPP.

Now I`ll start dealing with runtime expression. This is pretty simply but a good

understanding of the linstep function is needed. Below is the code i`m using to

make my particle switch to the next object (which is the next step in transparency).

Hope i`ve made this very clear and easy to follow.

Alin Sfetcu - VFX Artist

aSfetcu (at) gmail.com