tutorial reactor basics part 1[1]

8/8/2019 Tutorial Reactor Basics Part 1[1]

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1. IntroductionHave you ever heard of Reactor?Reactor is a great and powerfultool that comes with 3dsmax.Without it, you would not be ableto do very complex and physicallycorrect animations. This tutorialis a short introduction to Reactor.

With the help of two littleexamples I will illustrate Reactorworks.The picture above represents asmall scene I did in 3dsmax 6without any other plugins. Theidea behind the animation is quitesimple: Just imagine standing inan old church tower; it's sunrise

and the bells start to ring, and allthe mechanical parts start tomove.Hard to make without the help of reactor, isn’t it?Okay, to disappoint you: I am notgoing to explain how to recreatethe above scene at this moment.For now you must be satisfied

with a short introduction toreactor, and be patient, for theother parts will come soon.

Content:

1. Introduction 01

2. Reactor Basics 02

2.1. The Collections 03

Workshop I 05

2.2. Reactors Utilities 07

Workshop II 08

3. Conclusion 10 3.



2. Reactor Basics

What the hell is he talking about?What is Reactor?

Let us think back to the year1998. One of my favourite movies

came to the cinemas: “The Big Lebowski”.I really hope that every one of you knows that movie! If youdon't shame on you. Go to yourlocal video store, get that movieand watch it before you read on ;)

Alright, the Dude had one bigpassion: he loved to bowl. When Isaw that, I said to myself: lets goand create a small bowling-scenein 3dsmax.

I wanted to model the pins andanimate them when they were hitby the ball. Sounds easy, BUTafter hours of tweaking andsetting every single Key, I got anervous breakdown as I realized

that it is not possible to animate(physically correct) the wholescene by hand.

I closed the file and waited almost7 years, before I restarted theproject.

But why? What has changed?

Besides the first gray hair and afaster computer, 3dsmax 6 cameout. Included with it was a smallbut powerful plugin called

Reactor. I could not believe myeyes when I saw the results of mybowling scene. Since that daysome of my friends call me Gollumas I start to quote him as soon assomeone talks about Reactor.…my precious!” (just joking ;) )

Alright, if you open 3dsmax help(by pressing F1) and search forReactor you will find thefollowing sentence:

Reactor is a plugin for 3ds maxthat allows animators and artiststo easily control and simulatecomplex physical scenes.”

And that was exactly the type of thing I needed to animate mybowling scene. In fact the bowlingexample is really easy to handle

compared to the complexanimation we will get to at theend of this tutorial.

But enough of my anecdotes frommy early days of 3D. Lets learnsomething about Reactor and itspower.



2. Reactor Basics

As I said before: Reactor is aplugin that gives you full controlover complex physical scenes. It isreally easy to use, and with just afew clicks you can create greatlooking animations.

To get started, open 3dsmax 6.On the left you should see atoolbar with a lot of icons (like theone shown on the previous page)

You cannot find the toolbar?

No problem: Go to Customize –Customize User Interface. Inthe window that pops up click onToolbars, select Reactor anduncheck the Hide-Box.

In this tutorial, we will only needtwo Collections, but I am goingto give you a short overview of the most important functions, sothat you know “what is what” when you start to create your ownanimations.

2.1. The Collections

Create Rigid Body Collection

That is the first helper object youwill find on the Reactor – toolbar,and it's used the most. The RigidBody Collection is a necessary

small box”, where all of theobjects (rigid bodies) that are tobe animated get stored.

But what is a rigid body ?

Every object you have created can

be used as a rigid body. With thehelp of Reactor you can assignvarious physical attributes (likemass) which then effect theirbehaviour (a heavy ball actsdifferently than a light one).

Create Cloth Collection

It is the second button on thetoolbar, and as the name says ithas something to do with cloth.

The Create Cloth Collectionacts much like the Rigid BodyCollection. The difference is thatall of the objects that have a cloth modifier applied (which turns yourobject into a deformable mesh)get stored here.

It's basically the “small box” foryour deformable objects.Only the “cloth” that are stored inthe Cloth Collection will beanimated by Reactor.

Create Soft Body Collection

Soft Body Object have a soft-body-modifier in their stack.

All objects that will be flexed,bent, and squashed during the

simulation get stored here.

3 questions you should be able toanswer now:

1. Where have I stored my pins(from the previous bowlingscene)?

2. If you want to animate atowel with the help of reactor, which collection areyou going to use?

3. You created a plastic ball andwant to animate it. Whichcollection would be the best?

Answers: 1. RBC; 2. CC; 3. SBC



2.1. The Collections

Create Rope Collection

The Create Rope Collection isthe “small box” for rope-lik objects.

Every Spline-Objects in your scenethat has a rope modifier added toits stack, and will be animatedwith reactor, gets stored here.With the help of a rope modifieryou can turn a spline object into a

deforming 2-dimensional chain of vertices.

The rope modifier is very helpfulwhen you want to create (andsimulate) ropes as well as chainsor hair.

Create Deforming MeshCollection

Deforming Meshes or better “Skin-Objects” are a bit complicated to

handle. What is a deformingmesh?

In 3dsmax help you will see thatthe skin of a character, where anydeformation stems from theunderlying animated character rig,

could be used as a deformingmesh in Reactor.

Skin like objects should get storedin the Deforming MeshCollection.

Alright, that’s it for Collections.With the help of those fiveCollections you should now have asmall box” for every object in

your scene, so that it can be

animated with the help of reactor.

Before you can start animatingwith Reactor you have to createa mesh and store it in theappropriate Collection. Collectionsare helper objects (also called

dummies) that can be placedanywhere in the scene. Theplacement is irrelevant becausethey are not rendered. So: Thefirst step is adding your objectinto a collection.

Afterwards, you have to definesome physical variables of theobject like mass; which alter theobjects behaviour greatly.

In the Reactor Toolbar there is asmall button called “OpenProperty Editor.”

By the way, if you do not like towork with the Toolbar you canalso use the menu at the top. Justclick on Reactor – OpenProperty Editor.

The Property Editor is dividedinto three sections:

• Physical PropertiesMass, Friction, Elasticity

• Simulation Geometry• Display

I will not explain each of themindividually, as the 3ds max 6 helpdoes a great job. Just open help(press F1) and search for “RigidBody Properties.”



Workshop 01 - A simple reactor-animation

We have learned whatCollections are and where tochange the physical variables of the object. It is time for a littleworkshop, before you start to getbored.In this workshop we are going tocreate 2 objects (a sphere and abox) and let them interact withthe help of reactor.

In 3ds max 6, create a box and asphere.Place the box in the middle(0,0,0) and the sphere over thebox (0,0,50) (the value of the zcoordinate depends on the size of your object ;) ) – Examine the

above screenshot of myperspective viewport.Create (guess what) a RigidBody Collection. Select it fromthe toolbar and place itsomewhere in the scene. As said

perspective-viewport-screenshot

before: it really does not matter

where.

With the Collection dummy selected open its modify menu.

(I won't explain where to find it,because you really should know

where it is. This is not a tutorialfor newbies.)

Click the Pick – button and selectthe Box, then click on it again andselect the sphere.

the modify menu

Now that we have added both of

the objects into the “small box” we are able to animate them.

No we are not!!

We have to set the physicalproperties of the objects.

Select the sphere and open theProperty Editor.Set the mass to 50. (Hopefullyyou have checked 3ds max helpfor an explanation of theparameters.)

the physical properties of the sphere

Select the box and open the

Property Editor again. Make surethat the mass is set to 0.

That’s all, you have set up yourfirst reactor animation ;)



2. Reactor Basics

As I said before, the workshop isthere just to help cement in thelesson. If you feel comfortablewith the material, you do not have

to do it.

A few more buttons:

Analyse World

Once you set up your Reactoranimation use this utility to check

if there are any errors in yoursettings.

If it returns: “World Analysis gav no warnings ” you can proceed tothe next step.

Preview Animation

Clicking this button will open theReal Time Preview Window .Here you can take a first look atyour animation. You can use yourmouse to rotate the whole sceneand see the effects of doing so.Before you create your animationyou should always run the

preview to avoid any errors andlong renders.

Create Animation

If you are completely satisfiedwith the results in Preview, youcan use this function to haveReactor create keys for every

object in the animation

2.2. Reactors – Utilities

By now you should be able to usethese common tools to create asimple Reactor animaiton.What's left?

Gravity!

Go to Utilities and click onReactor (the picture to theright).Here you can change a lot of parameters which have a great

effect on the environment of youranimation.The most important one can befound in World > Gravity. Thedefault is –386,22 which is aboutthe strength of Earth's gravity. If you are making an animation in

space you should lower thegravity in this menu. You can also set this to a positivenumber which would make thingsfloat up; useful in an underwateranimation.

All of the others are explained ingreat detail in 3ds max help



Workshop 02 - An intermediate animation

Lets do another workshop ;)We will create three objects andmake them interact.

In the first workshop we created asphere and let it fall down. It wasa very simple animation and easyto make. This time we will go alittle bit more in depth withReactor tools.

Create:• a torus• a plane• a sphere

1. The torus should be in themiddle of your scene. (0,0,0).

Set Radius 1 to 50 and Radius2 to 10.

2. The plane should have alength and width of 300 with16 segments. It should beplaced just over the torus(0,0,30).

You do not have to use the samevalues as it is just an example, soit really does not matter if yourplane is just 150x150, but youshould create enough length andwidth segments as this is veryimportant later on!

3. The sphere should have aradius of 15 and be placedover the plane. (0,0,80).

The end result should be likesomething on the right.

What is the goal of thisanimation?The plane should act like a clothobject and fall on the torus (toruswill have a mass of 0 so that it will

hold its position). The sphere willalso fall on both.Since the plane will behave like acloth, the sphere will force itthrough the torus.Sounds complicated? With Reactorits done in minutes. ;)

We have to set all the of physicalattributes:

Select the sphere, open theProperty Editor (from Reactor –toolbar) and set the mass to 100.When done, select the plane andset the mass to 1. (Cloth is notvery heavy. ;) )

The torus should have a mass of 0because it is a stationary object.

We have set the physicalattributes and should be able tocreate our Reactor collections.

Before doing so, we must makethe plane behave like a cloth.



Workshop 02 - An intermediate animation

Select the plane, go to Modify andadd the Reactor Cloth to thestack.

Set mass to 0.01 (as said before:cloth is not very heavy). After thatscroll down and activate “ AvoidSelf Intersection.” (Look at the picture to the right)

If you do not activate it, thesimulation will look veryunrealistic as the cloth will

intersect itself when fallingthrough the torus.

There is one problem left to fix:Select the torus, open theProperty Editor and activateConcave Mesh. This makesReactor use the actual mesh of the object for the animation.Otherwise, Reactor would notrecognize the hole in the torus!!(To learn more about it: F1)

You should only use ConcaveMesh if absolutely necessarybecause it can make thecalculation time needlessly long if you use a complex model.

That’s it! Unbelievable!

You have created your secondReactor – animation.

You have created the 3 objects.

You have set all of the physicalvariables and you have added thecloth modifier to the Plane.

We still have to create thecollections:

Select the Rigid BodyCollection from the toolbar andadd the torus and the sphere to it.Select the Create ClothCollection and add the plane toit.

Now you can “Analyse World” and

start the preview.Hit “P” and be astonished ;)

As you can see animating withReactor is fast and easy to to do;)

After you have created theanimation you can add ameshsmooth modifier to the planestack for better looking results!

tutorial reactor basics part 1[1]

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