Realistic Animated Falling Snow

Author	darek
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File	Falling Snow By darek 4

Have you ever wanted to make falling snow in Blender? It’ s easy to set up a particle system, the tricky part is getting the movement right.

The Particle System

To make snow we’re going to use a feature in Blender called particles. First we need to make an object, which will be a sphere, then we need to set it to emit particles.

To make the particle emitter:

1. Open Blender and delete the default cube.
2. Create a new Sphere(Spacebar->Add->Mesh->UVsphere). Leave the settings at default. This will be our particle emitter.
   
3. Go into front view(1) and edit mode(Tab). Box-select(B) the top half and delete it. We don’t need it.
   
4. Go to the Physics Window and enable particles for the UVsphere.
   
5. These are the settings I used. Copy them for now but feel free to come back later and experiment.

   
   *Tip: 20,000 particles might be too much for older machines. You
   can put it down to 10,000. However, more particles do look better.

Extra Animation

If you play back the animation now(Alt-A) the particles should be moving very slowly down and away from the emitter.
It looks very boring at the moment. Have you ever noticed how real snow doesn’t move in a straight line but tends to float around in a general path? This is called secondary motion. (At least, that’s what I call it.) This is what we’re going for and we can do it by setting up some vortexes.

*Note: If you have an older computer Blender may become extremely low and/or freeze. This may be a good time to save.

To make the Vortexes:

1. Go to Front View(1). Set the 3d cursor to the middle of the large cloud of particles by simply clicking. Add a new empty.
2. With the empty selected go to the same Physics window we were at before. Select Vortex from the Fields drop-down menu. Copy the settings below.
   
3. Duplicate(Shift-D) the Vortex twice. Move the copies over a bit. Check to see they are spaced apart by going into Side View(3).
4. Duplicate it three more times. Rotate these so they’re at a 90 degree angle to the others.
5. Make sure the particles are going through the vortexes, and not just around them.

Now you should have 6 vortexes, three vertical and three horizontal,
placed randomly in the middle of the cloud of particles. It should look
something like this:

Materials and Final Touches

If you render it now, F12, it doesn't look very impressive.

We can improve it by making some changes. First we can change the background color from blue to black by going to the World buttons.

Now we give it a material. Materials define how an object looks like. My settings are below.

1. Change the color to white.(this is easy)
2. Set opacity to 0.5. Opacity is another name for transparency, which
   is another name for alpha. That’s what the A stands for. This make our
   snow slightly see-through.
3. Set the material to Halo. This turns each particle into an
   individual “halo” and allows us to control size and other aspects of
   each particle.
4. Change the halo settings. These are pretty self-explanatory. HaloSize sets the size of each halo. Hard controls how spread out each halo is. Add is usually used with effects like fireworks. It causes particles close to each other to make themselves brighter.

It’s best to try different variations and experiment for yourself. That’s the best way to learn.

Now it looks much better.