Arrows - TargetsIn this tutorial we are going to use Particle Flow and animated shape instance to create an effect of Arrows hitting targets and vibrating in place to give the illusion of impact.

We will need several things to begin which I have previously created for the purpose of this tutorial. You may download the starter file here:http://tutorials.diclementi.com/start_files/targets_start.max

Inside you will find 3 targets in a group, a wall behind the targets to deflect stray arrows, a ground plane to catch the ones that do not strike the targets, a gravity, 3 Deflectors (1 UDeflector for the targets, 2 Normal Deflectors for the wall and ground.), and 2 cylinders which will stand in for our arrows.

One cylinder is named arrow_straight and is not animated, the other one is named arrow_stick and has a few keyframes of the arrow bending back and forth a bit as if it has just been stopped abruptly.

These are all very simple things to create and animate and they should be familiar to you, if they are not you may wish to do one of the tutorials geared more towards beginners than this one first.

Download the file ( or create your own with the items I mentioned above) and open it up.

Then hit 6 on your keyboard to open up particle view, or find it in the Graph Editors menu at the top of your screen.

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Drag and drop an Empty flow in the empty light grey stage area, then select the title bar named PF Source 001 to adjust the system settings in the command panel to the right

We are going to use the icon as our emitter for this one, and our emitter needs to be much longer so that it spans across our targets well enough that some arrows will strike the wall, and others hit their target.

Change the Viewport to 100% so we can see all of the arrows in our system via the viewport.

Then in your viewport, grab your rotate tool and turn your PF_Source Icon until the arrow points at our targets. Then move it up and back so the icon is facing our targets and will fire particles in the proper direction from somewhere out of site off camera.

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Then return to particle view, and drag and drop a Birth operator in the empty light grey stage area below our PF Source001 box.

Connect the blue node from our first box to the empty circle node on our second box, Event 001. Then select the birth operator and adjust its settings.

I have chosen to have arrows fire for 150 frames and I have chosen to have 75 arrows. The amount and time is completely up to you and your scene in this case.

Next, add a Position Icon to the list between the birth operator and the display operator.

The default location of Volume will do us just fine so no need to make any changes here.

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Next, add a speed operator below our Position Icon.

We want our arrows to shoot out like they were fired by professionals here so give them a fairly High speed... I chose 1000, with a variation of 100. This can be faster or slower to your liking.

I also gave mine a very low divergence so they don't all look like they are being fired by persons of the same height and with complete accuracy. We don't want to go to high here or our arrows will miss the mark entirely.

Then click on the Display operator and change the top dropdown to Geometry so we can make our particles look like our arrows next.

Add a Shape Instance to the list below our speed.

Click on the large None Channel button in Particle Geometry Object, and then find and select your arrowstraight (the one without animation.)

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This will change your particles into arrows, sadly our arrows appear to be firing out straight up and down and this looks terrible.

So to fix our arrows to point in the proper direction, we need to add a Rotation operator to the list below the Shape Instance.

Change the dropdown menu to speed space follow, meaning they will travel in the direction that they are heading towards.

We will still have to define a starting rotation for our arrows so put 90.0 in the X: field and the Z: fields... this will change depending on which direction you modeled your arrows in, so keeping changing the fields by 90 degree increments until you see your arrows point forward in the future.

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This should straighten our arrows out and they should be firing with the black end forward and the yellow end backward.

Good, now we need to add some collisions based on which part of the scene our arrows collide with. Let's start with the arrows that miss the targets and hit the wall behind them.

Add a Collision operator to the list below the Rotation.

Use the by list button to assign the Deflector 002 to the Deflectors list (the one in front of the wall) Then make sure it is set to Collides and the Speed is Bounce. This will make our arrows bounce backwards when they hit the wall, indicating it is a harder surface than the target and the arrows cannot penetrate it.

Next we will need to make these missed arrows fall to the ground and land.

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The Collision operator is a Test operator, so it comes equipped with a new blue node on the side of the operator. We can use this node to send our arrows to a new event which describes new behavior.

We want our arrows to fall to the ground after they are deflected by the wall, so drag and drop a Force operator from the depot and place it in the empty light grey stage area below the Event 001 box:

Connect the new blue node to the empty circle node in our new Event 002 box. Then select the Force operator and using the By List button add the Gravity in your scene to the list.

This will make our arrows fall to the ground, we still wish to use the straight arrow for this portion of the effect, so change your new Display operator to Geometry in the top dropdown in its settings.

Then hold down the shift key until you see the little + sign above your mouse cursor, and click and drag the Shape instance from Event 001 to Event 002 to copy it.

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This saves us time and effort by copying over all the settings in the original operator to the new event and lets our particles look like our arrows from the original flight.

Next we need them to hit the ground rather than pass through it and continue falling. So add a Collision operator below our new Shape Instance in the Event 002 box.

Using the By List button, find the Deflector001 in the scene (this is the one on the ground) and add it to the list of deflectors.

Then set the radial button to mark the Collided Multiple Times and allow the arrows to bounce twice before they continue on to the next event.

You will notice that the arrows now bounce off the ground, but they keep sliding until they are off camera. This is not what we want, we want them to come to rest on the ground after a bounce or two. The best way to get something to stop in Particle Flow, is to give it a new speed and set that speed to 0.0. So drag and drop a Speed operator to the empy light grey stage area below our Event 002 box, and attach our newest collision node, to the new empty circle node in the new Event 003 box.

This means that after our collision lets the arrows bounce twice, they will begin moving at their new speed, which in this case is 0... so they will stop.

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Set your new Display to Geometry in its top dropdown again, and repeat the steps to copy the Shape Instance from Event 002 to Event 003 so we keep our textured arrow.

Something still seems wrong here, the arrows have come to a stop, but they are all pointing straight ahead and aren't exactly very convincing ... so let's add a bit of randomness to how they land.

add a new Rotation operator to the list below our Shape Instance that we just copied down.

Set the dropdown for the new rotation to Speed Space, then adjust your axis fields again to match our original rotation if you are using my starter file the numbers with be X:90, Y:0, Z:90 just like the last one.

A speed space gives us the option to add divergence to these axis, I have given mine a divergence of 20.0 which will definitely add randomness to the direction in which the arrows come to a stop on the ground.

We also have to turn on the Restrict Diverg. to axis checkbox, because we only want the arrows to diverge from the Z axis. Otherwise the arrows will look like they are sticking in and out of the ground all over the place.

With a 0.0 in X and Y, and a 1.0 in Z we get a randomized landing pattern for our arrows, but they all still lie flat on the ground.

Good, our arrows now bounce off the wall and land on the ground rather messily just as they should. Our next step is to make any of the arrows that hit the target stick into the target and wiggle slightly giving the effect of impact.

To do this we are going to add a new collision operator, but we are going to add it to the Event 001 box. Event001 is where our arrows are still flying through the air on their initial journey so that is where we want them to collide with the new deflector.

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Add a new collision to the list just above our original collision.

Using the By List button add in the named UDeflector (Targets) and set the Collides Speed dropdown to Continue.

This means that if the arrow collides with the Targets first, then they will get sent to a new event through the blue node in our newest collision operator.

We want them to stop when they collide with the targets immediately, so we can drag and drop a new speed operator in the empty light grey stage area below the Event 001 box, set this speed to 0.0 again, and then connect the newest blue node to the empty circle node in our now Event004 box.

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Set your new display to Geometry in the top dropdown for its settings so we can see the arrows in this event.

We will see a new colored arrow stop and stick when it strikes a target now, which is great ... but not great enough. We made and animated a special arrow for this part. One that wobbled back and forth a little to really give it that feeling of impact.

So below our newest speed, drag and drop a brand new Shape Instance operator.

This time add the second (animated) arrow to the None channel button... arrowstick.

as this one is an animated arrow check the Animated Shape box.Fast Shape Evaluation should show up as a default as well

Set the Animation Offset keying dropdown to Event Duration so that our animation place when this event begins for each arrow.

Congratulations! You have just finished an arrow effect where the arrows react differently to different objects. To see a finished example preview animation of the effect you can download the .mov here:http://animation.diclementi.com/arrows_targets.mov

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Hope you enjoyed this one! Try adding a few extra events and see if you can't get just one of our arrows to strike the bull's-eye dead center, maybe the only different colored arrow in the bunch!

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