Sandman Effect - PFlowIn this tutorial we are going to use Particle Flow to create an effect similar to the Sandman from the Spiderman movie.

To begin please download the starter file here: http://tutorials.render-test.com/start_files/sandman_start.zip

You can see a preview animation of the effect on a moving character here:http://tutorials.render-test.com/sand.mov

So that we can focus on the particle system and not worry about how to create deflectors and spacewarps you can use the start file from above. It contains a plane for the ground, with a deflector on top of it... the settings on this deflector have been adjusted to make the sand bounce a little and then settle on the ground so take a look at the settings on Deflector001 to get an idea of why I chose those settings.

It also contains a generic human figure model (you might recognize the default body from Mudbox) which could be any animated character you have as well.

On either side of this generic figure are two more Deflectors (002 and 003)... the default settings have not been changed as they will have no bearing on the reaction of the sand other than to trigger our particles to fall.

There are several Space Warps including 2 winds (001 and 002), a gravity, and a drag. Gravity will make our particles fall, the winds will add a bit of turbulence so the sand falls prettier, and the drag just slows the process down a little to give

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us a nice looking fall. Take a look at the settings for each of them to get an idea for the reasons I chose these settings and play around with them if you like to change your own effect.

I will not be going into detail on the settings for our deflectors and space warps as you should already know how these work by now, if you have no idea what I'm talking about I recommend closing this tutorial for now and starting with one that is geared more towards a beginner.

As I mentioned before, we will be turning this human figure into sand ... to do this we will need to create quite a large amount of particles. The deflectors on either side of our human figure will need to be animated passing over our human figure... the collision of particles when they come into contact with one of these deflectors will trigger our sand to fall from the figure to the ground giving us a nice collapsing sandman effect.

So to begin, we will go ahead and animate these deflectors.Turn on your auto key and move your timeline slider to about frame 150. (or whenever you wish the man to be gone, and the sand to be completely fallen to the ground)

Then select one of the two deflectors that I have placed on either side of our human figure, and move it through him to the other side. Then do the same thing to the one that was already on that side.

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Essentially we have animated the two deflectors to simply move through the figure and switch sides. The deflector on the right is now on the left, and the one that started on the left is now on the right.

Turn the Auto Key button off now, and then scrub down your timeline between frame 0 and 150 to see the animation.You should see the two deflectors move towards the center of the man and then continue to the other side like they are kind of scanning him.

Simple enough right?

Next we will go ahead and jump into Particle View by hitting 6 on your keyboard, or by finding it in the Graph Editors Menu at the top of the screen.

Drag and drop an empty flow operator from the depot at the bottom of particle view into the empty light grey stage area. Then click on the title bar labeled PF Source 001 to modify the settings for the system.

I have chosen to leave my viewport% this time at 50, because we are going to have a rather large amount of particles.

It may even be prudent to reduce this farther depending on how good your computer is.

I have gone ahead and added a few 0's to the Particle Amount Upper limit just to be sure I can see as many particles as possible.

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Next, drag and drop a birth from the depot to the empty light grey stage area below the first box created by our empty flow. Then connect the two boxes via the blue node on the bottom of the first, to the empty circle node on the top of the second Event 001 box. Like this:

Click on the Birth operator in the Event 001 box and adjust its settings in the command panel on the right.

For the purpose of this demonstration we want all our sand particles to be visible right away so I have set the Emit Start and Stop to 0. I have increased the amount to 20,000. to start ... by the time we are finished this will be a much higher number however, possibly even in the millions.

Next, add a Position Object operator between the Birth and the Display operators in our Event 002 box.

Not that we are not using an animated character for this tutorial, but if you want this effect on an animated character in the future you will have to check the Lock On Emitter box so that the sand particles follow the body.

Using the By List button, add the humanBody object to the Emitter Objects list.

Also note that if you are using an animated character you must check the Animated Shape box as well or it won't update.

The location for this tutorial we will use Surface, but if you want it to seem like your entire character is sand all the way through you could change this to volume. You will need a heck of a lot more particles in your birth however. Surface will do us fine for now.

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Now that we have our PFSource 001 box and Event 001 boxes created we are going to add a few operators to the first box. We add the operators in the top PF Source 001 box only when we want them to carry through the entire particle system. For instance, if I want all my sand particles to Display as brown dots, I can change the top dropdown to Dots in the Display operator currently at the bottom of the Event001 box and then simply drag and drop it from Event 001 to the PF Source 001 box. Like this:

----->

Now I can simply delete any new display operators that show up in our system and this display will work for all of our particles. You can change the display to Geometry as well if you like to actually see the particles in your viewport... If you have a decent computer, if not dots are fine.

Like the display, I want the same shape to be carried throughout the system. Add a Shape operator between the Render 001 and the Display 001 operators in the Top box of our flowchart:

I have left mine set to cube for this, as the particles will be so small no one will notice, and cube gives me less polygons to calculate in the finished product.

I have reduced the size to 0.3 to make the cubes small like grains of sand. This may even be good at a smaller size of 0.15 or so as well, but just to fill in the blank spots a little more I have chosen a higher value than that.

Check the Scale % box, and give the particles a variation of 35% ... this way all our grains of sand are not exactly the same.

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Next, add a Rotation operator below the Shape.

Leave it at the default of Random 3D ... this will help our sand look more natural by twisting the starting rotation of each particle in a random manner. No more straight up and down cubes.

At this point you can actually hide your humanBody object so you can see just the figure in sand.

Select the human figure in your viewport and right click to bring up the quad menu... then select Hide Selection.

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When the Quad menu disappears your model should be gone but the grains of sand should remain.

In order to fill him in all we have to do is increase the Amount in the birth operator... we will do this later on though. For now we can see the results well enough to continue.

Not that in the future we can add a Material Static to the top box PF Source 001 as well and give our grains of sand a texture ... but I think the flat color we have right now will be ok for the tutorial.

Next we are going to move back down to the Event 001 box, add a collision operator below the Position Object.

Using the By List button, add our Second and Third Deflectors only ... NOT Deflector001 yet.

The default setting of Collides will work fine, but change the Speed dropdown to Continue rather than bounce.

This will tell our particles that as soon as either Deflector 002 or 003 comes in contact with our particles that they should move into the next event in our particle flow chart.

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Before we add the next operator, be sure that your Timeline scrubber is set back to Frame 0.

Whenever you add a Spawn operator this is a good idea as they can get a little out of hand before we finish adjusting their settings.

When the slider is at 0, go ahead and drag and drop a Spawn operator from the depot to the empty light grey stage area below our Event 001 box... this will create an Event 002 box which we can connect to our new blue node on the side of the collision operator we just previously added.

The default setting of Once is fine

Make 100% of our particles able to spawn offspring

I have set my offspring to 3, in the finished effect I could add more than this, perhaps 5 or 6 but for now this will do.

I have decreased the Inherited value to 50.0With a variation of 50.0 and a Divergence of 35.0

This will let our particles lag behind the originals as they fall a bit, making it look as though there are more sand particles than we originally began with as they tumble to the ground.

In other words our original count of 20,000 will triple by the time they start falling.

Next, select the new Display 002 that showed up in our new Event 002 box, and right click and delete it.

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We do not need it since we want the one we originally moved to carry through the entire system so it is best to get rid of it or you will see all your new particles appear as tick marks.

Next, add a Force below the Spawn.

Using the By List button, add only the first Wind001 to this operator.

Then reduce its influence by quite a bit, I have chosen 250.... so the turbulence of this wind is used but to a more subtle effect.

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You can see how the turbulence is stirring up our particles by moving your slider down the timeline a little ways.

As the deflectors cross the path of the particles the turbulence from the wind is stirring them up a little giving us the idea of destabilizing our figure.

You may wish to replace the slider to Frame 0 once you are done looking at what our first force has done to the system.

Go back to Particle view and next, add another brand new force operator below the first one.

This time using the By List button, add the rest of the space warps.

Wind002Gravity001andDrag001.

Leave the influence at the default of 1000% this time.

Scrubbing down your timeline should now show them not only going a bit wiggly, but also falling towards the ground.

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Next step is to make them collide with the ground and gather in a pile at our figure's feet.

Add a new collision operator to the bottom of the Event 002 list.

This time using the By List button, add only the Deflector001 to the collision.

This deflector was the one on the ground plane, which we did adjust the settings on in the Modify tab.

We reduced the amount of bounce and increased things like variance, chaos, and friction so that the sand bounces up a little and then settles to the ground.

Set the new collision 002 operator to allow for Multiple collisions, the default of 5 is fine, and leave the speed set to Bounce.

Next we will get the particles to stop after they bounce a few times ... rather than kind of gyrate in place forever as they are doing currently.

Drag and Drop a speed operator from the depot, to the empty light grey stage area underneath our Event002 box, and connect the new collision node, to the empty circle node for the Event 003 box.

Reduce the Speed value to 0.0.

and Delete the new Display operator that comes with it.

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That's it! your effect is now completely built.

Simply adjust settings to your liking, for instance you can raise the birth amount to something extreme... for the example preview animation I began with 600,000 particles. http://animation.diclementi.com/sand.mov

The image here below is a starting amount of 100,000 particles and looks rather packed!

http://animation.diclementi.com/sand2.mov

Add textures, lights, etc. and you are done!

Try playing with the wind settings for a more chaotic dispersion of the particles, etc.

If your computer is having troubles with all these particles try adding a Cache operator to the top box in the flowchart, or a delete below our final Speed operator and give them a length of time before disappearing.

These are good ways to free up some computing power for these higher count particle systems.

I hope you enjoyed this one, it is always a fun one to create!

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