Tutorial 3: Raymarcher & The Explode Daemon

One of the improved features of AfterBurn 4.0 is the Explode Daemon. In this tutorial, you'll work more with the AfterBurn color gradient and noise settings as well as the AfterBurn Explode Daemon to set up a burning, fiery smoke effect.


The AfterBurn Explode Daemon lets you add color to an AfterBurn effect. This color can vary by distance from particle center or by density.


  1. In 3ds Max, select File->Open, and from your /Scenes/AfterBurn/Tutorials folder, select the file AB-Tut3.max.


When the file loads, you'll see a Plane object with a Noise modifier applied to make it look like terrain. If you scrub the Time Slider, you'll see a Snow particle emitter spraying particles upwards, like a geyser.


  1. Go to Rendering->Environment dialog and from the Atmosphere rollout click Add.
  2. Select AfterBurn to add an AfterBurn entry to the Effects list.
  3. From the Source Particles/Daemons list box, pick the Snow01 particle system.
  4. From the Source Lights list box, pick the Direct01 light.
  5. In the AfterBurn Manager rollout, check the Show in Viewport button under the Display group of controls.



  1. Advance the 3ds max Time Slider to frame 60. This will help to visualize the Sphere radius parameter we are going to tweak.


As you can see, the particles show up as small spheres. These spheres represent the size of the AfterBurn volumetric puffs that are to be applied to the Snow particle system. Unfortunately they are much too small right now, but we can change that.


  1. Under the Particle Shape rollout, right-click over the Sphere Radius AFC and select Enable.
  2. Set the Low value to 50.0 and the High value to 120.0.



As you do, you'll see the spheres in the scene increase in size.


  1. Select the Camera01 viewport and render frame 60.



As you can see, the size looks right, but the noise is too small and looks incorrect. You'll change this next to something more appropriate.


  1. In the Noise Animation rollout, set Density to 2.0.
  2. Right-click over the Noise Size AFC, enable it, and set the Low value to 30.0 and the High value to 80.0.
  3. Render frame 60 again.



The noise size now looks about right for the explosion effect you're designing. Now we'll start to spice up the smoke effects with the Explode Daemon.


  1. In the 3ds Max Command Panel, go to Create->Helpers and choose AfterBurn Daemons from the dropdown menu.



  1. Select Explode then left-click and drag to create its icon anywhere in the viewport. (It creates an X-shaped gizmo)



NOTE: The Explode Daemon has another unique capability to limit the range of its influence to the AfterBurn effect. As you don't need this capability it doesn't matter where you create it in the viewports.


  1. In the Command Panel, go to Modify mode.
  2. Right-click over the Color Gradient field (the white rectangle) and choose Load.
  3. From the /Scenes/AfterBurn/Tutorials folder, load the explode.agt gradient.



To associate any Daemon with an AfterBurn effect, you have to make AfterBurn "aware" of the Daemon by selecting it within the AfterBurn Source Particles/Daemons list box.


  1. Back within the AfterBurn atmospheric, click the Pick Particles/Daemons button, and add the Explode01 Daemon to the source list.



  1. Inside the Colors rollout, right-click over the Color 1 gradient field and select Keyless mode. In this mode, the gradient is functioning just like a standard 3ds Max Color Selector box.



  1. Left-click on the gradient to bring up the Color Selector, then set the color to Dark Gray (RGB: 50, 50, 50).


This is necessary as we want the Explode Daemon to control the color of the fire and smoke entirely. Be aware that by not setting the color to black, that there will be some subtle shadowing contributed from the original gradient when we eventually have the effect cast shadows.


  1. Activate your Camera01 viewport and render frame 60.



You're getting there, but right now you should notice that the entire smoke plume is colored the same way. This is incorrect. We want to avoid that and make the explosion more fiery at the beginning and black at the tail.


  1. Go back to the Explode Daemon rollout. You can also edit AfterBurn Daemon parameters without leaving AfterBurn UI. All you need to do is to select AfterBurn Daemon inside Particles/Daemon list and it's user interface will show up among other AfterBurn rollouts.
  2. Right-click the Color Key Shift with Age AFC and enable it.
  3. Right-click the Multiplier AFC and enable it.


You will tweak the multiplier to make the beginning of the smoke look more "hot" than the tail.


  1. Set the first Multiplier value to 3.0 and leave the second Multiplier value at 1.0.



  1. Now, render frame 60 again.



This is now starting to look like an explosion. But the AfterBurn effect still needs some shadows to add some realism.


  1. To add some shadows, go to the AfterBurn Rendering rollout and check the Self Shadows box.


Before you render again, you also have to enable the Direct01 light shadows.


  1. Select the Direct01 light, and from the Modify panel, enable the light's Shadows checkbox and Atmosphere Shadows checkbox.
  2. Render frame 60 again.



That looks pretty good. If you like render out the entire animation to see how the rising fiery plume looks over time.
With the current lighting setup, AfterBurn engine is using raytraced shadows through volume, which is slow. To speed up rendering, we are going to tweak current scene and use AfterBurn Shadow Map.


  1. Select Direct01 light and change shadow type from Shadow Map to AB Shadow Map.
  2. Uncheck Atmosphere Shadows option, as we do not need this method when using AB Shadow Map.
  3. Inside AB Shadow Map rollout, set Size to 200 and Bias to 0.5
  4. Render. Notice speed improvement.
    To get better quality with AB Shadow Map, there are few things you can do.
    - make hotspot/falloff  as tight as possible
    - decrease AfterBurn's Shadow Step Size
    - increase AB Shadow Map's size and quality

With this tutorial, you've learned how to associate AfterBurn daemons with specific AfterBurn volumetric effects. Moreover, you've seen how easy it is to build some thick, dense smoke by combining standard AfterBurn color gradients and the special effects look of the AfterBurn Explode daemon. Moving ahead, you'll next get to see how to quickly model clouds using standard 3ds Max geometry.