Letter Collision Tutorial.

This tutorial will help u make a basic collision in 3Ds Max using its inbuilt reactor feature.

Requisites:-
discreet 3Ds Max 7 (Does 6 have reactor?? I dunno....). Even the trial downloaded from discreets

website will do.

Time:- 20-30min.
Skill Level :- Beginner (A basic knowledge of the menu items is a must for this tutorial)

Introduction:-
reactor is a plug-in for 3ds max that allows animators and artists to easily control and simulate

complex physical scenes. reactor supports fully integrated rigid and soft body dynamics, cloth

simulation, and fluid simulation. It can simulate constraints and joints for articulated bodies. It can

also simulate physical behaviors such as wind and motors. You can use all of these features to create

rich dynamic environments.

Once you have created an object in 3ds max, you can assign physical properties to it with reactor.

These can include characteristics such as mass, friction, and elasticity. Objects can be fixed, free,

attached to springs, or attached together using a variety of constraints. By assigning physical

characteristics to objects like this, you can model real-world scenarios quickly and easily. These can

then be simulated to produce physically accurate keyframed animations.

When you have set up your reactor scene, you can preview it quickly using the the real-time simulation

display window. This allows you to test and play with a scene interactively. You can alter positions of

all physical objects in the scene, dramatically reducing the design time. You can then transfer the

scene back into 3ds max with a single key-click, while retaining all the properties needed for the

animation.

reactor frees you from having to hand-animate time-consuming secondary effects, like exploding

buildings or draping curtains. reactor also supports all standard 3ds max features such as keyframes

and skinning, so you can use both conventional and physical animation in the same scene. Convenient

utilities, such as automatic keyframe reduction, let you tweak and alter the physically generated

parts of an animation after it has been created.
(Taken from 3dsmax User Reference)

Now, this tutorial focuses on creating the individual letters of a word. You will learn how to make a

ball collide with the word and get the individual letters to interact differently.

Ok, First we will create the basic scene requirements.
I
1. Fire up the software.
2. Goto Create->Shapes->Text.
3. In the text editor type the first letter of the required word.
4. Be sure to select the renderable option in the letter properties.
5. Place the letter anywhere in the scene.
6. Repeat the process for all the individual letters. You can alter the text later by selecting the letter

and clicking on the modify tab on the upper right hand side bar.
7. Now apply the extrude modifier to all the letters by opening the modify panel ->Modifier

list->Extrude. Change value to 5.

II
We have finished creating the individual letters. Now, to create the "ball"
1. Goto Create->Standard Primitives->Sphere.
2. Drag and create a sphere such that it covers the letters that you want it to collide with. Move the

sphere a distance from the word.

Now the sphere is ready, But once we try to animate it in reactor all the letters would fall down into

space with the ball. To avoid this we would give the sphere some velocity and create a plane for the

letters to fall on. To create a plane
1. Goto->Create->Standard Primitives->Plane
2. Drag and create a plane below the letters and covering all of them.

III
Now to give the sphere some velocity.
1. Select the sphere.
2. Turn on Auto-Key. The time bar turns red.
3. Take the timer to Frame 10.
4. Now drag the sphere horizontally to the other side of the word. Use movement in only one axis to

avoid any errors.
5. Switch of auto-key.

We have now given the sphere some velocity but it would just go through the letters, thats not very

realistic is'nt it?? This is where reactor comes in.

IV
1. Select ALL the objects in the scene and click on reactor->Create Object->Rigid Body Collection.
2. Select all the letters of the word.
3. Goto reactor->Open Property Editor.
4. Change mass of to 1 and under Simulation Geometry change selection to bounding box.
5. Select the sphere and similarly change its value of mass to 2 and select bounding sphere.
6. In plane propeties ONLY chane sim. geometry to "concave mesh"
7. Open the utilities panel from the upper right side and goto->Reactor->Preview and animation->

Change start frame to 2.
8. Now save your scene.

V
We are now ready to view what has been created.
1. Goto reactor->Preview animation.
2. In the window that comes up check if you can see all the objects.
3. Press 'P'
4. You should see the sphere crash through the letters. If the sphere does not hit the word, try

adjusting the positions.

If you are satisfied with the result goto reactor->Make preview.

VI
Now lets convert this into a video.
1. Goto Rendering-> Render.
2. Under File Output click on files.
3. Select the location and the file type. Select any video extension (.avi, .mov etc.)
4. In time output select Active Time Segment.
5. Finally Click on render.
6. Once the file is finished close the windows and view your file.
Congratulations!!! You have successfully created a collision!!

Now since you have an idea you can use this to create a variety of simulations....Also refer the user

reference files and tutorials under help. Have Fun!!

Experienced users can also try many more things to enhance the look and appeal of the video. For ex.
1. Apply materials to the objects (A reflective plane looks good)
2. Creating a camera and linking it to any letter to get the camera to shake after the collision.
3. Getting the plane to rotate after a while would make the letters slide down.
4. After doing the above^ you can create some lights and link it to individual letters.
5. You can link the camera to a letter and watch it fall down and chase the letters. Dont forget to

increase the time of scene. You will have to change the end frame in IV accordingly.

You can e-mail me at [email protected] if you have any problems or suggestions.
Hope i was helpful.

NAKUL