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In this scene showing a fighter plane taxiing on a runway, you will use a particle system to simulate heat distortion.
If the sunset image is not visible in the viewport, use Alt+B to load up the image you downloaded for this tutorial.
The jet wash from the engines creates the heat distortion effect you often see in the movies.
Before you start this tutorial, you need to render the existing animation to disk.
In the Render Scene dialog, set the Time Output to Active Time Segment.
Save the Output File name as Fighter plane or FPlane
and set it to .png
Set the png format to 24bits with no Alpha Channel.
Save the Animation to disk. This could take a good 15 to 20 minutes, depending on the speed of your system.
When the rendering is done, disable Save File to disk and set the render output to Single frame.
Make sure you are at Frame 0 and go to the Particle Systems panel.
In the left view, create a PF Source icon slightly wider than the tail wings.
Make the height about equal to that of the fuselage.
You will adjust the particle system in a moment but for now, adjust its position in the Front view just ahead of the reactors.
Link the particle system to the fuselage so that it travels with the plane.
Do not worry about the particles behavior at this time, you are about to change that.
With the PF Source selected, press 6 to access the Particle View dialog.
The basic event contains a set of operators. You will adjust their parameters and add more operators as needed.
Start with the Birth. This defines when and for how long particles are going to be emitted.
Set the Emit Start to -100. This ensures that some particles are already "alive" by the start of the animation.
Remember the plane is already taxiing and not just firing up its engines.
Set the Emit Stop to 200, so that new particles are generated throughout the animation.
You can set the amount of particles by a fixed number or by rate.
Rate is calculated by second. Set the rate to 1000. You will be changing that later.
Next, skip the particle positioning. They're based on the surface of the PFlow icon which works well for this scene.
Select the Speed operator and decrease the speed to about 5.
This may seem low but you'll actually rely on a wind effect to simulate the turbulent jet wash.
Skip the Rotation operator and move to the Shape operator. At this time, the shape is a 3D cube.
However, it is hard to see because the particles are displayed as ticks.
Click the Display operator and set its type to Geometry.
If you want, change its wirecolor to a light color so you can see it better.
The boxes are too big. Go back to the Shape operator and set the size to about 0.25
Now that you've adjusted the size, set the display back to Ticks, or better yet to Dots, to help with viewport performance.
Particles do not, or at least should not "live" eternally. Add a Delete operator after the Speed Operator.
Set it to operate by Particle Age and set the Life Span to 80 with a variation of 10. This way, the life of a particle will last between 70 and 90 frames.
To help create turbulent jet wash, go to the Space Warps panel and create a Wind icon in the top view.
Set it to Spherical.
At frame 0, position it just under the particle system.
Link it to the plane's fuselage so that it travels with it.
At this time, it does not yet affect the particle system. For that, you need another operator.
Insert a Force operator right under the Delete operator.
Add the Wind effect to the Forces list.
Currently, the effect is very strong and needs adjustments.
In the Modify panel, bring down the Wind Strength to about 0.02.
Set the Turbulence to about 0.1 and the Scale to 0.05.
Set the Frequency to 1 and playback the animation to see the effect.
Experiment with these values until you get an effect you like.
Try also repositioning the wind icon a little further toward the front or the back of the fighter plane.
To get a better effect, go back to the Birth Operator and set the rate to 10000. The final effect will look better with more particles.
Finally, you need a material for the particle system.
The heat distortion effect will be finalized in post, after you render the scene and the particle system separately.
You already rendered the geometry. For the particle system rendering, you only need a white particle system over a black background.
Therefore, go to the Material Editor and create a Standard self-illuminated white material.
If you wish, you can set its outer falloff to 100% to make it softer on the outside.
To apply this material to the particle system, you need a Material operator.
Since this material is not animated, you can use a Material Static operator.
Instance the material you created to the Material Static operator.
You may need to disable, then re-enable the operator for a quick refresh.
Make sure the particle system is selected, and then right-click and hide everything else (Unselected) in the scene.
Render the camera view and notice the problems.
One problem is that we still see the background in the render. That's easy to fix in the Environment dialog.
The bigger problem is that the particles are very dark, even though they are set to be self-illuminated.
This is because of how the rendering is set in this scene, the use of a Daylight System, mr Photographic Exposure, Physical Scale and Final Gather.
All these are important to render the geometry but not the particle system in this case.
Set the Physical Scale to Unitless with a value of 150000.
Disable Final Gather and render again. That's better.
Go to the Render Dialog and set the Time output to Active Time Segment again.
Give the output file a name, such as jetwash and save it to a png format.
Render the sequence. In the next movie, you'll use Autodesk Combustion to simulate the heat distortion effect.