In this tutorial, you will learn how to create realistic imprints, such as tire tracks or footprints, on surfaces like snow, mud, or other deformable materials. This technique can be used on a variety of objects, rigid or deformable, or even adapted into other interesting variations of your own!

Note: click the ‘Monitor’ icon to view tutorial in full-screen HD.

Step 1

Create a Plane and change the name to “Deformable Plane”.

Step 2

Set the plane’s Length and Width to ’140′ and disable “Real-World Map Size”.

Step 3

Move the “Deformable Plane” to the coordinates: x = 0, y = 0, and z = 0.

Step 4

Create a new plane, change the name to “Emitter Plane” and set the Length and Width to ’120′.

Step 5

Move this plane to the coordinates: x = 0, y = 0, and z = 140.

Step 6

Press the ‘A’ key on the keyboard to turn on “Angle Snaps”. Now, rotate the “Deformable Plane” by ’25′ degrees on the ‘x’ axis.

Step 7

Clone the “Deformable Plane”. Set the clone type to “Copy”, and change the name to “Deflector Plane”. Press OK.

Step 8

Move the “Deflector Plane” to the coordinates: x = 0, y = 0, and z = -10.

Step 9

Near the “Deformable Plane” create a Cylinder. Set the Radius to ’4′ and the Height to ’30′.

Step 10

Near the Cylinder create a Teapot. Set the Radius to ’12′.

Step 11

Finally, near the Teapot create a Torus. Set the Radius1 to ’13′ and Radius2 to ’3′.

Step 12

Go to the “Command panel > Create > Particle Systems > Thinking” menu, and place a “ThinkingParticles 3″ icon in the Viewport.

Step 13

Go to the “Modify” panel and click “Properties” in the “Thinking” rollout. You can also use the hot keys of ‘Alt + Shift + P’ to open and ‘Alt + Shift + C’ to close the “ThinkingParticles 3″ user interface.

Step 14

In the “DynamicSet Tree” view, select “Master Dynamic”. Disable “Edit on the fly” to see the changes in real time. Enable “Show Mesh” to see the particle shape.

Step 15

In the “Particle Group Tree” view, click the “Create” button, under “Master System”. Name the group “Objects” by clicking on the name “Group” two times (slowly). Next, you need to create a “Dynamic Set” to dictate what the particles do.

Step 16

In the “DynamicSet Tree” view, click the “Create” button, under “Master Dynamic”. Rename the new “Dynamic Set” with the name “Generate”, as you did previously with the “Objects” group.

Step 17

Highlight the “Generate” “DynamicSet”, and then go to the right-hand side of the dialog, where you will see a new set of “Create” rollouts.

Step 18

Select the “Operators” icon, and then choose “Generator” from the drop down list.

Step 19

Select the “Matter Waves” node to highlight it, then click in the schematic portion of the “Wire Setup” view, to add this node to your “DynamicSet”.

Step 20

In the “Matter Waves” rollout, on the right portion that appears, click the “Pick Object Based Emitter” button, and select the “Emitter Plane” in the viewport. Select “Objects” as your “Group” from the drop down menu. Change the “Particles / [s]” value to ’2′, the “Life Span” value to ’300′, and the “Speed” value to ’0′.

Step 21

Minimize the “ThinkingParticles 3″ interface. Now, set the “Animation Length” to ’200′, and play back the animation to see the particles emitting in the viewport.

Step 22

Maximize the “ThinkingParticles 3″ interface. Highlight the “Generate” “DynamicSet”. Go to the “Create” panel, and from the drop down list select “Shape”. Add a “Geom Instance” operator, near “Matter Waves”.

Step 23

In the “Geom Instance” rollout, click the “Pick Object” button, and select the Cylinder, the Teapot, and the Torus.

Step 24

Click on the “Born Particle” output of the “Matter Waves” operator, and drag a wire to the “Particle” input of the “Geom Instance” operator. Now these parameters are connected: when a particle is born, a random shape (cylinder,teapot or torus) will be assigned to it. Move the time slider to see the changes.

Step 25

In the “Create” panel, select “Standard” from the drop down list. Add an “Alignment” operator, and connect the “Particle” input to the “Born Particle” output, of the “Matter Waves” operator. Now the particles use random vectors for the alignment.

Step 26

In the “DynamicSet Tree” view, select “Master Dynamic”, and click the “Create” button. Rename the new “DynamicSet” with the name “Dynamics”.

Step 27

In the “Create” panel, click the “Groups” icon. Add the “Objects” group, in the schematic portion of the “Wire Setup” view.

Step 28

Click the “Operators” icon, and from the drop down list, select “Dynamics”. Add a “Force” operator.

Step 29

In the “Force” rollout, change the “Strength” value to ‘-100′. Connect the “Objects” group to the “Force” operator. This will act like a gravity force for the particles.

Step 30

Create a deflector for the particles by adding a “PhysX” operator, and in the “PhysX” rollout, select “Objects” as your “Group”.

Step 31

In the “Create” panel, click the “Helpers” icon. Add a “Node” helper, and in the rollout that appears, click the “Pick Node” button. Select the “Deflector Plane”.

Step 32

Connect the “Node” output to the “Floor Node” input of the “PhysX” operator. Play back the animation. Now the particles should collide with each other, and with the “Deflector Plane”.

Step 33

In the “DynamicSet Tree” view, select “Master Dynamic”, and click the “Create” button. Rename the new “DynamicSet” as “Imprints”. In the “Create” panel, click the “Operators” icon, and select “Tools” from the drop down list. Add a “Collision Map” operator.

Step 34

In the “Collision Map” rollout, click the “Pick Object” button, and select the “Deformable Plane”. From the drop down menu, select “Objects” as your “Group” . Change the “Map Width” and “Map Height” to ’512′.

Step 35

Click the “Select Record File” button, and select a path for the movie that will be saved. Name this “Collision.mov”. Click the “Record” button. A progress bar will appear, and you have to wait until the simulation is complete. The “Collision Map” tool creates an animated map that contain the information of the collision between particles and the “Deformable Plane”. Open “Collision.mov” to see this animation.

Step 36

You can now close the “ThinkingParticles 3″ interface, and hide the “Deflector Plane” and the objects. Select the “Deformable Plane” and set the “Length Segments” and “Width Segments” to ’100′.

Step 37

Add a “Displace” modifier from the Modifier List. Set the “Displacement Strength” value to ‘-10′, and choose the “Collision.mov” file for the “Displacement Map”. Change the “Blur” value to ’0.3′ and the “Map Length” and “Map Width” to ’142′.

Step 38

That’s all. Move the “Time Slider”, and notice that the imprints follow the shape of the objects very well.

Final Effect

I hope you enjoyed this tutorial. Below you can see my final results.

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