Dissolving Models with Particle Flow and Animated Opacity Map In this tutorial we are going to start taking a look at Particle Flow, and one of its uses in digital effects of making a model look as though it is dissolving into dust. This is a more advanced method and requires a bit of a better understanding of 3DS Max and Particles Systems. As such I will assume if you are trying this tutorial out that you have a decent knowledge and understanding of the program and it's more basic points. To start open a new 3DS Max file, and create 2 things. First, make a teapot and second create a wind space warp. Position these two items with the end result in mind. We are going to make this teapot dissolve into dust and blow away in the wind. I've given my teapot a radius of 40 and 8 segments, just for looks. The wind I have given a strength of 0.25 and left it set to Planar. Give it a Turbulence of.7 Frequency of 5.0 and Scale of 0.05 This will change up the pattern of our wind instead of blowing our dust particles in a straight line.
Your scene should look something like this so far. Now that we have the objects we will need in our scene, we can open up the Particle Flow window. Hit 6 on your keyboard, this should bring up a new window that we will use in creating a flow chart of what our particles will do. **if hitting 6 doesn't bring up the empty particle flow window, then look at the top of your 3DS Max window and find the button that looks like - - This is the keyboard shortcut override toggle and as long as it is depressed will allow us to open the particle flow window by hitting 6** You can also get to this window by going up to the main menus, clicking on Graph Editors and then down to Particle View. You can also create a particle system from the create tab called PFlow, the only downside to this is that it will start you with default flowcharts and you will have to spend time removing them in order to build your own.
One way or the other, you should now have a new window in front of you that looks like this: This is the Particle View window. Here we have complete control over what our particles do at any given moment in our animation. It lets us script out events and how the particles will act, react, or change over time. Don't let the lists of items scare you, it really is all pretty self explanatory after you get used to it. The large empty grey area, is where we will drag and drop items from the below list and connect them with lines and arrows. The list below in the white area, is all of the "events" we can add, modify, and place in our flow chart area. The dark grey are to the right side, is all of our settings. Depending on what we have selected in our flow chart, the settings here will change. Just like the settings in our Modify tab.
First things first, we need to create a new system. Right click in the empty grey area in the Particle View window: Find New -> Particle System -> Empty Flow. This will create a new Particle Flow system in both our viewports, and in the Particle View flow chart area. An orange icon will appear in your viewports, this is the PF Source we just created. In your Particle View window you will see the same name PF Source. Here it appears like a box in our flow chart. Click on the Render 01 (Geometry) icon in the flow chart, and notice that the settings come up in the dark grey area of Particle View on the right hand side of the window. These are the settings for the new PF Source we just created. Here we can adjust how much of the particles will be visible in the Render, and what they will appear as. Leave everything here at the default for now.
Next we need to start selecting and dragging out "Events" from the list in the white area below the flow chart. Find the listing that says "Birth" and click and drag it out to the empty grey area just below the PF Source node we just created and then drop it. Like this: When you have done so, you will now have two boxes in your flow chart. The original PF Source, and now a new box labeled Event 01. This is the beginning of our particle system. In other particle systems you may have used each particle is told when to start and stop, and how many particles we are going to have total. It is the same here, only we are placing the settings ourselves.
Before we adjust the settings we need to link our PF Source 01, to our Event 01. Notice the little blue line with a dot at the end of it just below the PF Source box? Click on the dot, and drag and drop it in the empty circle above the Event 01 box. This will link them together and tell the flow chart pieces that they are related to one another. As long as a dotted blue line with an arrow at the end of it points from one to the other, we can continue. Click on the Birth Icon in the Event01 box, and go over to the right to adjust its settings. These settings should appear familiar to you if you have had any experience up to now with particles of any type. Emit Start: 0 - This is when the particles will start emitting from our object. Emit Stop: 50 - This is when the particles will stop emitting from our object. Amount: 50000 - This is how many particles we will have in total. Set yours to match mine for now, we can always come back later and adjust to our liking further. Now that our particles have a place to begin, we need to tell them what they will begin to emit from. In our case, it will be the teapot we started with in the beginning of this tutorial.
Head down to the list of events again, and find one that says "Position Object". Then click and drag it into the Event01 box with our Birth event in it, and drop it right between the Birth 01 and the Display 01 events in the box. Like this: If you dropped it correctly, the new event will now appear in the Event01 box between Birth and Display. ------------------------->
Click on the Position Object 01 and go over to the right side of the Particle View window to adjust its settings. Click on the "By List" button under the Emitter Objects. From the resulting list choose the Teapot we created in the beginning, and then click on the Select button. <--- It should then appear in the empty Emitter Objects: list. Now scrub back and forth in your timeline and see what we just did. You should see all kinds of little tick marks being generated on the surface of the teapot from frames 0 to 50.
We have successfully told the teapot to be the emitter for our particles. Next, we need to tell our particles to obey the wind spacewarp we made in the beginning of our tutorial. Go back to your Particle View window, and this time in the list of Events, find Force. Click and Drag the force event to between the newest Position Object, and the Display01, just like we did before. Drop it in between. --------------------------->
Then click on the Force01 icon, and adjust its settings to the right. Once again, click on the "By List" button, and select our wind from the resulting menu. ------------------> Again, check out the results of adding the wind to the flow chart in your viewport by scrubbing back and forth along the timeline. Our particles are created, and now are moving with the wind away from the surface of our teapot. So far so good. Our particles still need a bit of guidance, go back to your Particle View window and find in the events list the one that says "Shape" Drag it and Drop it just below the force like before.
----------------> Click on the Shape event and adjust its settings to the right like before. This is going to further define what our particles look like. Anything from spheres, to tetras, or cubes. This is also where we can adjust how big our particles are going to be in the final render. Experiment with these settings to figure out what might work best for what you wish to accomplish. For the purpose of this tutorial I have just set the particles to appear as 3D Cubes, and given them a size of.35.
When finished go back to your Flow Chart area, and click on the last icon in the Event01 box. The Display event that we have been avoiding since we first created our Birth. This setting lets us choose what color we want our particles to be, as well as what the particles appear as in our viewport. Click on Display 01 and look to the right for the settings: I have selected Geometry from the drop down under Type: This will show us our cubes in the viewport. I have also changed the color here to match the color of our current teapot. If this was more than a tutorial, we would definitely want to change this from a color to a real texture, but for our demonstration purposes, getting the colors of the teapot and the particles as close as possible is good enough. That's it for the particle system. Our particles are complete. you can now close down the Particle View Window. Only one thing left to do now, and that's make it look as the our teapot is vanishing as our particles break off and fly off into the wind. To accomplish this, we will use a simple animated opacity map. So please open your material editor (M).
In your material editor choose an empty texture slot, and change the diffuse color to match your particles. In my case it was a pinkish purple color. Then once you have a matching color, assign it to your teapot and then click on the Opacity map button either by finding Opacity in the Maps rollout, or by clicking the empty box button next to Opacity marked above. Find and select "Gradient Ramp" from the list.
In the gradient ramp we are going to do a few things. As this is in our opacity map channel, this will be how we are going to make it appear as though our teapot gradually blows away into dust. In order to accomplish this, we are going to custom animate the Gradient ramp, and then add some noise. As with any gradient editing program, you will see the gradient, in this case, black to grey to white. The three markers along the gradient are where the full change in color takes place. Clicking on the gradient anywhere else outside of these markers, will add another marker that you can change. Click in the middle of the gradient to add a fourth marker. You can then click and drag these markers to various positions along the gradient, in combination with the position numbers above the top right of the gradient that tells you what the RGB color is for said marker, and the Pos number or (Position) number along the gradient from position 0 to 100. You can change the color at each marker, by double clicking on top of the marker itself. Do this now, for each marker and turn all 4 colors to white. White is the color assigned to fully opaque in an Opacity Map, Black is fully transparent and anything in between will vary based on how light or dark the color is. Double click each marker along the gradient and change the color to white for all of them. We want the gradient to be fully white at first, so that our teapot is also fully visible, or fully opaque.
Next, move the second marker in from the left, to Pos=1. Then move the 3rd marker in from the left, to Pos=2. Great, now we can begin animation. Turn on your auto key button, and then move the timeline scrubber to keyframe #70. ------> Then return to your Gradient Ramp, and the 4th marker at Pos=100. Double click and change the color to black.
Move the third marker to Pos=99, once it is at Pos=99 double click that marker and change it to black also. Then move the second marker to Pos=98, and then double click the second marker and make it black. Then lastly double click on the first marker and make it black as well. Good. This will make more sense soon, I promise. Now with auto key still on, go back to the timeline scrubber and move it to keyframe #2. Look at your Gradient Ramp now. All the colors at this end of the timeline are still white, but at frame #70 we have changed them all to black. A couple more changes and we'll be ready to move on.
At frame #2, go back to your gradient ramp and double click on our 1st marker, to make it black. Do the same for the second marker at frame #2. Now scrub back and forth down the timeline to see the changes. The black color should animate and move down the gradient, slowly overtaking the entire white gradient ramp, with black. Look at your teapot and your texture in the material editor. It should slowly be moving from fully visible, to invisible.
Next, lets add some noise to this line so it doesn't vanish in a straight edged line. If Auto Key is still on, good. If not, turn it back on. Below the gradient in our Gradient Ramp Parameters, you will see the Noise: settings. (note: don't open the rollout entitled noise, just the settings in the Gradient Ramp Parameters.) Move your scrubber back to Frame #70. Then increase the Amount: setting in your Gradient Ramp to 1.0 from 0 and mark the radial button named "Fractal" Turn the Auto Key off, and check out the animation on your texture now by scrubbing back and forth along the timeline.
Hopefully it should be vanishing in an irregular pattern now. Make sure to add a "UVW Map" Modifier to your teapot on the modifier tab and adjust the gizmo to give you the best results, then you are all done! Render out your animation and make any necessary tweaks.