Learning Particles

In addition to composite work for the game trailer project i’m also handling the bulk of particle effects and the main particle effect that is a must in this particular project is fire.  Despite spending many hours in 3DS Max I am troubled to say that I have never delved down the particle effects road.  Not even working in game engines like Unity or Unreal have I played around with particles, usually because I’m stuck trying to figure out some ambiguous line of code.  But that has finally changed and I’m glad to say a lot of the preconceptions I had over creating particles have been broken.  It’s really not that difficult to get a handle on, unless ofcourse you have 30 million particles trying to render on the screen at the same time.  Yeah that’s a spoiler.

So after making two different styles of fire and smoke I can say at this point in time that particle creation involves two aspects, Creating the behavior of the particle and creating the look of the particle.  Starting with the behaviors I made a lot of mistakes that ended up costing me hours and they were really silly mistakes that looking back make me cringe.  After creating the particle emitter or the pflow as its called in 3DS Max I then added a wind force modifier which would give me a lot of options for the style I wanted.  However after playing with the various options for hours I just could not get the fire to behave the way I wanted.  Instead of coning inwards at the tip it was instead fanning outwards looking more like a sideways mohawk instead of a frontal one.  However by chance I dragged the wind force above the emitter which pushed the particles the other way, so after seeing this I tried to enter a negative number into the ‘Strength’ modifier not thinking it would work, but to my surprise turns out it does.  And with that realization the particle behavior performed almost exactly how I wanted.  Tweaking the turbulence, scale, and frequency modifiers for a little bit more gave me the result I wanted.

With the behavior of the particles sorted it then came down to making them look good.  For this project I only want to use materials instead of creating my own textures in order to get more creative with the material editor.  What I came up with was to use a composite map for the opacity settings which enabled me to combine a particle age and gradient ramp map together.  By doing this I could roughly simulate both the fire and smoke opacity over time with the particle age and also make the particles softer around the edges with the gradient ramp.  The colour of the particles was simply by adjusting the diffuse colour, except with the fire particles which I used a particle over age map, once again playing around with various colours to get the look I wanted.  Then lastly I added another particle age map to the self-illumination of the fire particle.

Not both particles were built the same though.  My first attempt, whilst produced a very nice looking particle, it was however a computer chugging experience.  It mainly worked just off simple gradient diffuse maps with 5% opacity, and the principle was the more particles I had the better it looked.  Unfortunately to get it visually appealing it took just shy of 30 million particles.  At this amount my computer took a vacation every time I clicked a button.  It wasn’t until a few hours after this I gave up for the second fire particle which I detailed above.  I unfortunately didn’t take photos of the particles but I did render out both sequences.  Enjoy.



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