Wednesday, March 17, 2010

Particle Dispersion Effect Using 3DS Max and Particle Flow


There are lots of similar animations on the Internet but I couldn’t actually find a good tutorial that is explaining how to create effect like this so here you can find one. First let’s take a look at the final animation and a sample screenshot from the middle of the movie.



That’s what we are going to create but before we start I’d like to point out some possible methods of creating this effect that I’m familiar with and some situations where you may find it useful. Effects like this one are usually very basic stuff and at the same time they have a wide usage anytime when you want to:

  • dissolve,
  • explode,
  • burn,
  • destroy,
  • hide,
  • and more…

something in a quick, simple and believable way. You can do it using different techniques and some examples include:

  • using modifiers such as “delete mesh”
  • using plug-ins like RayFire that are affecting object’s mesh
  • using materials that are not affecting mesh but making object invisible.

Here I will show you the third method because that one works best for me and is probably the best one in most cases, especially, when it doesn’t have to be perfect. Also it’s probably the quickest one to do and it gives you relatively the best results. So, of course you don’t have to play with all your mesh because it is much more complicated, time consuming and hard to calculate on average computer that you are probably working on at the moment, than if you had to use particles that are in a matter of fact made for such things. We won’t even touch our object (excluding a need of selecting it occasionally) but we will hide it using materials instead and let particles simulating sand appear in the correct place and time.

Step 1 – Objects to disperse

Open up your Max and create some kind of an object. I chose teapot because it is more complex and has more details than other objects. It doesn’t really matter if it’s big or small. I used 40 centimeters for radius so I was playing with quite big teapot :) . Don’t forget that size does matter if you are going to render your scene. Some rendering engines works better if you keep real world dimensions.


Step 2 – Setting Up Particle Flow

Once you’ve done that turn on Particle View window. Usually it’s under 6 hotkey so you only have to hit 6 right after you’ve made teapot but if it doesn’t work go to Graph Editors -> Particle View in the top menu of your 3ds Max. Right click in the window that will appear and create Empty Flow (under Particle System section). Then create Birth right next to that and connect them together (find part of table that makes your mouse cursor like 3 arrows pointing to the center and drag and drop this part of your table on the top of another).


Step 3 – Modyfing Particle Flow

We have to modify a list of items by adding there some new objects. Right-click again and add Position Object, Force and Shape from a list.

  • Position Object – because we want to add our teapot (or whatever you are using) to a system
  • Force – because we want to add wind (otherwise particles won’t fly away)
  • Shape – because we want to see particles on renders

We have to modify all of them slightly before we can go any further but first let’s add one more thing to our scene.


Step 4

Go to Space Warps, choose Forces and then Wind. Place it somewhere on your scene. Again it can be either big or small as you wish because it doesn’t make any difference except it’s easier to find in viewports. I made it around 10 meters. Rotate and move it a bit so that it has direction in which you want your particles to fly. You can also make it falling ground but in this tutorial I’ll only cover flying.

Once you have your wind you can modify its setting. I found that standard wind’s strength is too high so it’s good idea to decrease it a little bit. Also you’ll probably want to add some turbulence to it so that it won’t go perfectly straight. Try to change other settings here if you won’t satisfied when we’ll be able to see the result (we can’t yet).


Step 5

Go back to Particle View and select Position Object. Add your teapot to Emitter Objects list.

Step 6

Now choose Force and obviously you have to add there your forces. In our case there is only wind.

Step 7

Go to Display and choose there your particles’ color as well as their type. I decided to make them look like a sand so I think Dots and yellowish color will be great.


Step 8

Now select Shape and decrease its size a lot like for example to 1cm or 2cm.

Step 9

Go to the Birth and change Emit Stop to something bigger like 50 and Amount to something really high. I think 20,000 would be enough for now but for the final renders you’ll probably need to increase this number to around 100,000 (depending on how many particles you need). Finally we can close that and get back to viewports and our teapot. Animation is already there. Maybe values I chose are not good for you but always you can play with them as you like. Now it’s good time for that. If it slows down your computer don’t worry. You can go to your PE Source settings and look for Quantity Settings. Decrease Viewport % a bit and it will show less particles in your viewport but still they will be visible on your renders.


Step 10

We can get back to our teapot again. We want it to disappear and that can be done using gradient ramp as an opacity map. Opacity slot as many others works that way it grabs value from color of any grayscale map and make your objects more or less transparent. For instance, if you will put there black bitmap it will be invisible all the time because black has value of 0. Go to Material Editor (M) and select one of the material slots. Select opacity slot and then change it from NONE to Gradient Ramp.


Step 11

Basically what we want to achieve is animated material which will make teapot disappear while there are particles flying around. We need to animate gradient and make it change from white at the beginning to black at the end during 100 frames. It’s a bit complicated process. Try to even set key frames for already set indicators (colors)(for instance if indicator is already white set it white again anyway when you move it to another position). Turn the Set Key mode on and go to the 1st frame.

  1. Frame: 1 – 1% indicator set to black and rest white at positions 2%, 3% and one at 100%
  2. Frame: 2 – 1% and 2% indicators set to black and rest white at positions like before (remember to change their color to the same color here even if they already have this color – this will make key frame)
  3. Frame: 98 – move indicators from 2% and 3% to accordingly 98% and 99% (1% indicator is black and 2% indicator is white all the time)
  4. Frame: 99 – 99% indicator set to black and rest black but 100% is still white
  5. Frame 100 – 100% indicator set to black and rest are black

Now you should have nice gradient moving from left to the right. It may be hard to achieve so I’ve prepared a video presenting whole process. Make sure to turn on Set Key mode as I did and to press key button each frame to create a key frame.

A couple things to note:

  • to see material’s key frames on your time line you have to add this material to teapot or other object first
  • you will have to move key frames then because particles are starting to appear slowly and you want your teapot to disappear only when there is a lot of particles already and not right after animation starts.

Step 12

If we now render that at for example 50th frame it will be ok for some objects but not for teapot. You have to add some mapping to it. Modifier called UVW Map should work fine with standard settings but simple objects like teapot. Animation is ready. It looks almost or exactly like we wanted to but you can play with gradient a bit and make it softer or add there some noise to make effect better. I’ve set my noise amount to 0,08, size to 0,93 and mode to Fractal.



Well, that is all for now. I hope you enjoyed my tutorial. As I mentioned you can use this effect in variety of ways. Especially it is useful when you are going to burn something and want to burnt part of your object disappear, when you want to make an explosion and want your object to disappear consecutively part by part. It doesn’t require much calculating power as it is with modifying mesh and gives you quite good results.


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