The Mechanics of Motion Automation in 3ds Max 2019

STEVEN SCHAIN: So my name is Steven Schain, a.k.a. the 3D professor, which is not up there. But I worked for 4D Technologies out of their Ashville office. I run their post-production facility as well as develop their media and entertainment Content. I have been an Autodesk trainer and user of 3ds Max since 3D Studio DOS release 1 and 3ds Max since release 0.1. I remember looking at it going, oh, my God. I could take a cylinder and bend it in real time. It was amazing. Rendering it was a different story but the animation capabilities have come a long way. But it was still an amazing leap from DOS. Anybody remember the 3D Studio DOS era? A couple people. So we've come a long way since then. How many people are using 3ds Max 2019? Wow. Quite a few. And how many have gone back to release, let's say, 10? No? OK. Good.

So welcome. We're going to learn a couple of things today we're going to look at four different animation tools in 3ds Max. We're going to look at wiring. So we're going to take care and we're going to wire some parameters together. That's going to be simple. I've done this not necessarily in order of complexity but in order of the way I put it together. So then we'll look at creating a piston that uses look at constraints. So how many people that are using 3ds Max or using any kind of constraints look at path constraint? OK. So it's good. And feel free to ask questions. Depending on how fast we get through everything today-- hopefully we'll get all the way through. Hands on labs it's hit or miss if we get through everything. So I want to caveat that now so when you fill out the survey you don't dig me on it.

We'll look at rigging a simple mechanical scissor joint that automatically works using bones and IK. And then we'll finish up creating a key frame animation with wired sliders, manipulators in the viewport. When I worked for a company called Star Media years ago I was managing 45 animators. And I was also the guy who helped rig everything and ran there R&D dept-- just did way too much. Well one of the things that I like to do was create onscreen sliders for animators to do things like adjust pitch roll and yaw of the airplane that we were animating. So if you're animating it, you adjusted the pitch. And based on the angle of pitch it would automatically go up or go down. So it was a couple of scripts that ran. That was pretty nice. So we did this but just the question of, who uses 3ds Max on a daily basis? So a couple of people? Anybody weekly? Anybody never use it? OK. That's all right that's why you're here.

I don't know why there's an Autodesk Inventor question there but I'm going to ask it anyway. Actually, no. I do know why. It's early in the morning. This class was originally animating Autodesk Inventor assemblies in 3D Max. And this excavator is actually a CATIA file. It's the low resolution version of a high resolution CATIA file that I used for a Volvo construction equipment animation. But a lot of people who use Inventor bring the files in and rig them up. And what is useful is you can take these techniques and use them for mechanical motion. So we're going to start. I'm going to go through the slide show first and then we'll get and just go right through all the hands on. If that's OK with everybody? That way you sort of see what we're going to do, and then we'll just go right through it all.

So we're going to set the project folder. How many people who use 3ds Max use project folders regularly? Anybody use like a project data management tool? No? Does everybody who doesn't use project folders have a specific folder structure that they work with? Good. Thank you. Yeah, you can use Vault. OK. So you're checking stuff in and out. Yeah. Yeah, as long as you have some organized way of doing things, that's important. One thing that I like is I like the way 3ds Max uses project folders. I don't know if you're aware, but you can customize your project folder set up to be anything you want. It doesn't have to be the default for 3ds Max. So there is a project file that is in the folder and that can be anywhere. So what it does is it just tells 3ds Max where to go for everything. So even if you're using your own custom configuration, you can put a project file into that root folder, assign that in 3ds Max and it will know where everything goes.

So we'll set the project directory. We're going to wire parameters for a very simple gear rig setup. So we'll do some parameter wiring. We're going to be setting the rotation value of the parameter wiring. And then we're going to look at-- next. We're going to configure Pistons for an industrial hinge. This is all going to be using the excavator rig that I developed for this animation. So the rig is-- let me grab my pointer here.

So what we're going to be doing is we're going to be working with these two pistons right here creating dummy objects that we can then link and then assign a look at too. And that will do what's happening here and here and it'll maintain a piston. So you'll have an industrial piston that just works. I like to, when I create things-- who does rigging? Anybody? So you just make things that just work. It's just easier when you're animating. So it's a basic rig. Pretty simple structure. We're going to create this dummy object, copy this dummy object. And we're going to have the dummy look at the little one and this look at the piston. So they're going to look at each other. But the reason why you have two dummy objects here is look at objects can't look at each other. It's as cyclic redundancy. It doesn't work. Yeah.

So we'll configure that and then we'll take a short quick two minute break. Then we'll look at rigging the excavator bucket and we're going to create a bone chain. So we'll set up a hierarchy. Don't let that intimidate you, folks that are new. It's not that difficult. We'll link everything, create an IK chain, and then go through and you'll see that it just works when you move the bones. And then we'll animate the assembly by using these manipulators up here. And that allows us to rotate the rig and move the arm and rotate the bucket. So we will go through and do that. And this will be the end result. And then I'll thank you guys for your time.

So let's get to it. I'm going to switch over here real quick, because we need to show you where we're getting the files from. So I'm going to sit down and disappear here for a sec. So up in the upper corner-- Everybody has 3ds Max open? 3ds Max 2019 is really nice. They've taken and created a tool pallet now for your project folders. In the past, you'd go to File, Project, Set Active Project. You can still do that. So if you click on Set Active Project, it is the same as coming up to the toolbar and clicking Set Active Project here. So the project is in Data Sets, Share. And just raise your hand if I'm getting ahead. And one of the lab assistants will help you. Oh, you know what? Before we move on got our lab assistants in the back. You guys want to introduce yourselves real quick?

LAB ASSISTANT 1: [INAUDIBLE]

LAB ASSISTANT 2: [INAUDIBLE]

LAB ASSISTANT 3: Nathan [INAUDIBLE]

STEVEN SCHAIN: So if you're running into a problem, raise your hand, one of them will come and help you. So the nice thing is, if you go to Data Sets, Share and you scroll down it's the only lab with FTV in it. So look for FTV Mechanics of Motion Automation in 3ds Max 2019. Double click that, go into the project folder, go into the project folder again and that's where you want to stay. So when you're done, just click Select Folder and you're good to go. So everybody able to do that? So now when you click Open you should get this list of files. And if you don't get that list, raise your hand. And I'll leave this up for a minute. And then I'm going to switch over.

All right, through the magic of television, we are ready to move on. I'll leave that here. So I hope you guys don't mind I have my cheat sheet. As much as you practice this, having a cheat sheet is always a good thing. And the lab assistants have the same cheat sheet, except they don't have page three. Go figure, printed it out before I got coffee this morning. All right, so we are going to open GearWiring01. So open that. You can double click it, or click Open. And this should actually go fairly quick. So what we want to do is we want to be able to rotate one gear and have the other gear automatically rotate. So the idea with wiring is you can take a parameter-- and it doesn't matter what parameter, it's any animal parameter inside of 3ds Max-- can be wired to any other parameter inside of 3ds Max as long as it is the same type of parameter. So you can't have a number be assigned to a vector.

So if you have a color value you can't say the color value equals a direction. A vector would just be a direction like whatever direction it's going. Now, the angle of that direction can be is a number, it's a value, it's a floating point number. So you can take that angle and say, based on the angle, affect the color. So you can have the y angle effect the red color and put a formula in there so as something turns it changes the color. I do that with a lot of dials, and switches, and knobs, and things like that inside of 3ds Max. So if you want the brightness of an indicator to automatically go when you animate the knob, you can set the self illumination of a material to be based on the angle of that knob. So that's what we're going to do here.

Just a caveat, angles in 3ds Max are done in what are called radians, which I think 1 radian like 54.68 degrees if somebody remembers right. Something like that. But there is a tool you can do, it's rad to deg, that you can program in there. We're not going to get into that. So don't worry about it. So we are going to select the large gear cylinder and if you press the E key on the keyboard, you get the Rotate tool. And those of you who are not familiar with 3ds Max, when you press the W, E, and R key you get Move, Rotate, and Scale. So the E key opens turns on Rotate and it gives you the Rotate tool. And you can rotate this around the y-axis. And you'll see I just have a simple rig here for this piston. And we're not going to go into this is a look at. It's just simple stuff.

So we're going to right click-- Somebody over here? So we'll right click on this and down towards the bottom-- and let me know can you guys see that well enough? No? Yes? No? Sort of? You want me to scale the text on screen? Think that would be better? No? It's good? You could see it in the back? All right. So select Wire Parameters. We're doing the Transform Y, So you're going to hover over Transform, Rotation, Y-rotation and you're going to get a rubber band line. So that rubber band line will allow you to sort of pick anything you want. It'll highlighted as you go over it. We want to pick the small shaft. And we're going to do the same. We're going to do the Transform Rotation, Y-rotation. And if everything goes well you should get the Wire Transform Dialog. Does everybody get that? Is there anybody who didn't get that? So we'll give it a sec here.

So while we're waiting for everybody to get up to us, so the Wire Transfer and dialog, you don't have to use the right click and select Wire Parameters from the right click menu. You can open the Wire Parameters dialog just by going to the Animate panel. Go ahead. A question over here? So you can just go to Animate Wire Parameters. You don't have to use the right click, it's just easier. Because what you get when you right click and you select Wire Parameters when you pick on an object, you get access to all of the wireable parameters for that object without having to dig for it. So if you look at the Wire Parameters dialog you have two sides, the left side and right side. The left side is the first object that you picked. The right side is the second object you picked. As you're working through your wiring you're going to decide what's going to be the master and what's going to be the slave for that set.

AUDIENCE: [INAUDIBLE].

STEVEN SCHAIN: Oh, let's turn Auto Save off. So everybody just for this, go to Customize, Preferences. And in Files, Auto Backup, turn that off. So I'll do that again. Don't do that at work.

[LAUGHTER]

So go to Customize, Preferences, turned off Auto Backup. That's good to know in here. One thing, a quick aside about Auto Backup. One of the things that we used to do is we had a single repository on our network for all the Auto Back files. I would have everybody put an underscore and their initials in the Auto Back. And all it was for was, because those were backed up daily on our network, if you ran into a problem on files you were working on at least had three or four backups of the files you worked on in the last couple hours. And I told everybody backup at least 30 minutes because five minutes is ridiculous, and 30 minutes to an hour is the most you want to lose. I know there were times where if I lost 30 minutes of work I was just-- you know, you're putting your head in your hands going, No. That was the best work I've ever done.

[LAUGHTER]

STEVEN SCHAIN: So we have three options here. We have a bi-directional control, and two one-way controls. So a one-way control is the knob is going to increase the brightness. If I increase the brightness, I don't necessarily want the knob to rotate. So I might want to increase the brightness because of I want to change that the ratio of brightness to the rotation of the knob. Well, I'll have that as a one-way value. Here we want both so that if the master and the slave both rotate, I want them to go one or the other, doesn't matter. And then here, down here we click Connect. That is going to connect the two. And if I come back to rotate it's going to move this out of the way. Notice that they're rotating the same direction and they're rotating the same speed. That's no good.

In the expression for the gear shift I have two options. I can either change this expression, which won't work. Or I can change this expression, which will work. So you don't want to change the expression on the master, generally. You could say the master rotates twice as much as the slave. But in this case, we want this to be negative y. So I'm going to come over here in the equation and say, negative y rotation divided by 2.

And then in order to see that, click Update. And now what you should get-- oops. Sorry. I wired these backwards. So instead of divided by 2, it's going to be multiplied by 2. So this is the dangers of doing a live class. We pick things in the wrong order. But if negative divided by 2 didn't work, multiplied by 2 will. So you get the same result, just a different expression. And the reason why it didn't work is because we selected the larger gear cylinder first and the smaller one second, when in the original plan it was the smaller one first and the larger one second. But either way, it works. You just change your expression to update the rotation. Does anybody have any questions on this? Yes? No?

AUDIENCE: [INAUDIBLE].

STEVEN SCHAIN: So that's sort of the simplest way of using expressions in wiring. And wiring can get very complicated, you can have wired parameters that affect other wired parameters. You can really have things that are very, very controllable in 3ds Max. And you can also wire something that does not render as part of the scene. One thing that I had built years ago was an altimeter. So all the numbers were wired together to rotate at a certain percentage of the number next to it. And I had a dummy object that I'd just animate up and down in the scene. And animating that dummy up and down rotated the very first number. So as that went up it would rotate. Well, every other number rotated based on that first number. And it worked. It just worked.

And that's what the whole idea of automating animation inside of 3ds Max is for. You want stuff that just-- it just works, you know. I use air quotes on works but it just works. Because you'll always have an animator that breaks it. We had 45 animators and I had one guy that I'd give him a rig and it was perfect and it worked he's like, I can't get it to work. I'm like, what are you animating? I'm moving in the plane up and down. Like, no. You're not supposed to. That's what this slider is here for. So there's that one guy in your department that you go, OK, we're going to make this different for him.

So that's wiring. So it's fairly straightforward. There's a couple of different ways to get to it. I will show you the other way to get to it you can go to the Wire Parameters dialog-- and click the Wire Parameters dialog here-- and it will show you the parameter that's wired and then, like I was saying before, you sort of have to dig. Thankfully this is pretty simple but you sort of have to dig. But you have the read value here, goes to the green value here. All right? So let's move on. We're going to go ahead and open a new file. And we're going to open the-- and this one is going to take a little bit more. We're going to open-- this on page three guys so. Yes?

AUDIENCE: I'm just curious, [INAUDIBLE]?

STEVEN SCHAIN: Yeah. Yeah, so whatever the ratio of the gears would be is-- and thank you because I meant to say that. But yeah, so whatever the ratio of the gears are. I just happen to make those 2 to 1 If they were 3 to 1, I would divide it by 3 or multiply it by 3. And if you have some weird gear ratio, you just use that value. Yes?

AUDIENCE: [INAUDIBLE]

STEVEN SCHAIN: Yeah. You can go into the schematic view. I'll open it. I tend not to show the schematic view. Let's see. I tend not to show this very much with people that are new but you can come in here-- oops-- and you can mess around and get to see what's wired to what.

AUDIENCE: All right.

STEVEN SCHAIN: Yeah. So it does it does allow you to see that visually. The schematic view, in my opinion, needs a lot of work. Yes?

AUDIENCE: How did you get to the schematic view?

STEVEN SCHAIN: It's this right here. Looks like a little hamburger with an arrow in it. And that gets you to the schematic view.

AUDIENCE: So you can't wire in the schematic view?

STEVEN SCHAIN: Yes, you can. Yeah. The schematic view is-- actually, it's a really powerful view. How many people use Maya? Couple of people? So it's the same idea. You can wire in the schematic view. You can do quite a bit. You can set up your hierarchies, you can wire. If you get comfortable using the schematic view, it's a very, very powerful tool. I would like to see a little more done with it to make it more usable. But it is a really powerful tool. So if you get comfortable with the schematic view, yeah, you can do a lot.

AUDIENCE: In a complex machine, there's a lot of interaction between several parts. I think it might be easier.

STEVEN SCHAIN: Yeah. And you can visualize some of that. There's a lot you can't, but you can visualize some of that. What I tend to do though is when I work on large complicated assemblies, I'll dumb them down. So this is a rig for a four million polygon excavator, what we're going to open now. And this is going to be excavator_arm_hinge01. So we go ahead and open that. And what I like to do is I will look at my high-res geometry and I will take that high-res geometry and I will build a low-res version of it. And that low-res version will have one object for as many objects as I could possibly link to that object. And it just makes life a lot easier. So a low resolution rig is always the best way to go to animate a high resolution object.

In years past I've taught people who were animating this high resolution rig, or high resolution object, and you run into so many problems. Not only are you trying to pump through a ton of polygons. But you're trying to rig something that has 500 parts instead of, how many of those parts could just be attached to one object that don't need to be part of a hierarchy? Which is why you'll see this rig, the piston, and all that stuff, on the high resolution version there's fittings there's hoses there's all kinds of stuff that get attached. But all that stuff gets attached to the boom arm because it all goes at the same way so it's all moving the same way. So rig it as easily and as simply as possible. Create stand-in geometry that is as simple as possible.

All right. So this is the page that you guys are missing. I'll hold it up here you can read it. So we're going to go-- Does everybody have the file open? OK. I'm going to keep an eye on time. We go till 10:00, right? So we're going to change over to Sort By Layer. How many people organize their scenes by layer? Everybody? If you start using a lot of objects, set layers up, it's a lot easier. You can nest layers too in 3ds Max so you can have layers within layers. So we're going to turn off layer 0, we don't need that. We need the arm helper. So if I turn that off you'll see that the helpers disappear. The arm model also we want to keep. So you want to keep that on. We don't need the bucket geometry right now so turn that off. We don't need our cameras, right? We don't need the excavator body geometry because we're not focusing on it. We don't need the ground. We don't care about that. We don't need the lights, and we don't need the manipulators. And the object layer is empty but we'll turn that off.

So all we're worried about right now is the arm helpers and the arm model layer. Now since we're going to be creating a helper, to the right of the eyeball click the layers icon. So we want to set than that as our current layer. We've got a question over here? Lab assistant? So does everybody have something that looks like this? Yes? All right. So the first thing we're going to do is we're going to create a dummy object that's going to be used for this upper piston. So go to the Create panel, Helpers, which is the little protractor there, click Dummy. And we're going to do this in the top view. We're going to click and drag out. And you can make it any size you want. And we're going to be moving this up here in a minute.

And the view you make this in is important. As those of you who are familiar with 3ds Max might know, depending on what view you make something will depend on the orientation it gets created. So if I create something in the top view, it's going to be oriented to the top view. If I create something in the left view, it's going to be oriented to the left view. So create things in the correct view, it'll save yourself a step. So those of you who are just new to 3ds Max, if you're going to get in and start learning it and using it, that's sort of the first rule of thumb I teach people is create it in the view you want to make it. It just saves you a little bit of time and a few steps. Do you have to? No, you don't have to but it's easier. All right. So do not select this object, leave it selected. If you click and drag again you'll create another dummy but come up here to the align tool. And click Align. Don't click and hold, that will give you a fly out.

And then in the front view here click on this cylinder. And what we want to do is if you click it correctly, you should get this Align Selection dialog. Can everybody hear me well? We want pivot point to pivot point in x, y, and z. All right? Good. Click OK. And let's go over to the Modify panel and let's name this up here. And this is going to be named-- let's make sure we got the right one-- dummy_boom_piston_link. I was telling the lab assistants, I should have made these a little shorter. We got Somebody over here? Yes? So I'm just going to highlight the name up here in the upper right. And I'm just going to type in dummy_boom_piston_link.

And when I name things I have a naming convention for everything that I do, generally. There are some objects if they're inconsequential objects to what I'm doing, I probably won't name them they might be box1 through box500. But anything that's important in the scene I will name. So dummy objects, any kind of helper object, any major object that I'm working with will be named. You'll see some scenes that just have circle1, circle2, circle3. Yeah? Who cares about that, right? When I was teaching though, my students would get a grade off for everything that was named Default.

So the next thing we want to do is we want to-- so we have that positioned and then we're going to create another copy of it. And we're going to move on to page 4. You guys have page 4. So we're going to come up here, you can click Select and Move or press W on the keyboard, either way. Or you can right click. 3ds Max there's like 10 ways to skin a cat. So make sure you have this dummy object selected, hold the Shift key down, and when you hold the Shift key down make sure you go over this corner otherwise, you're going to go left or right. Really doesn't matter. And you're going to click and drag to create a copy. And that copy can go anywhere because we're going to align it. And we want to create a copy not an instance.

And the reason we don't want to create an instance is it instances all the controllers as well. So we want this to be a copy, it's going to have its own controller, it's going to be linked separately. Is everybody there? Let me know if you're behind. Click OK. So we have this copy and we'll name this differently. So we'll name this dummy_boom_cylinder_link. So it's dummy_boom_piston_link01. I'm going to come up here, get rid of the 01. I could have renamed it in the dialog if I wanted to. Six one way, half dozen of the other. So this is dummy_boom_cylinder.

And then press Enter. That'll accept the name change. Come up to Align-- and so everybody with me? Let me know if you're not. Anybody? Can I move forward? Yes? Good. So we'll come up to Align, we're going to align this to the boom cylinder upper there. Your Align Selection dialog will remember the last set of selections you chose. So just click OK, that aligns it to the selection. Now we have to be careful because now we're going to select and link and create a hierarchy. So the hierarchy is going to allow us to link objects together, set up a child and parent relationships so that one object goes where the other object is. And here you have to be careful because if you set it up wrong your link is not going to work. You're look at is not going to work and your objects are not going to move the way you want them to move.

So we'll first select the upper piston boom, boom piston upper. Click on Select and Link, which is over here. It looks like a little chain link. Then we're going to click and drag from that chain link to that dummy. And the dummy will flash. What that's doing now as it's telling the piston that that is a child of the dummy object. OK? Next, select the dummy object. So just click once on the dummy object. Don't click and drag or anything, just click once. That'll select it. And here we might need to zoom in. That is going to get linked to this boom arm here.

So as that boom rotates, that dummy object is going to stay in position relative to that boom. And if you notice, it's sort of cantilevered around this pivot point here. So this point is the pivot for that boom arm and all the other parts will go along with it. Then we'll come over here and we're going to select-- and this one is-- let's just make sure we're doing this the right way.

All right. So here's what we're going to do. We're going to select the dummy_boom_cylinder_link. OK? That is going to get linked to that upper arm.

So clicking on the look at. And again, let me know if I'm getting ahead of anybody. Yes?

AUDIENCE: [INAUDIBLE].

STEVEN SCHAIN: Oh, sorry. It's named dummy_boom_piston_lookat. That's the name of the dummy object.

So just click on that and select it, and then click and drag that to the boom as well. So you're going to have both of these dummy objects connected to the boom arm, to that first arm. Now, select that cylinder. And we're going to link that cylinder to the bigger dummy object. We could link it to either one, it doesn't matter. But we're going to use the smaller dummy object as the object that the piston is going to look at. So we want to link this to the larger dummy and what that will do is that sets up the hierarchy for what we want to do. So we want the two dummies to move with the arms when the arms move. We want the smaller dummy that's just going to be there for something to look at, to move along with it. It's just there to look at. It's not doing anything. And then those pistons are tied to the dummy objects that are going to move along with the arms.

So does anybody have any questions so far? Yes?

AUDIENCE: So do you have to have the two dummy objects in that one location?

STEVEN SCHAIN: Yes. And the reason is that the way you set the look at up, you could have just one dummy, you could actually have one dummy. But you would have an issue with looking at the two objects looking at each other. Because you can have the dummy look at the cylinder and then the cylinder look at the cylinder but it just gets convoluted.

AUDIENCE: [INAUDIBLE]

STEVEN SCHAIN: Yeah. So what this is doing is it's giving me a little bit more flexibility so that the look at dummy object could be anywhere. It just happens to be where I need it. But I could place that wherever I need to. So if the piston is off just a little bit and it's cantilevered on something, I could actually set it up that way with that look at. It just makes it so that I know I'm not going to get a redundant look at setup.

So once you have the hierarchy configured, now it's time to set up the look at constraints. And here we're going to going to use the dummy object here to look at the cylinder. So select this lower dummy. And you can do it a lot of different ways. In the handout I think it's slightly different. So we'll come up to Animation, Constraints, Look At Constraint.

And we'll click it and we'll get a rubber band line. And I want this dummy object to look at the base of the cylinder.

And if you click it you should get that. It's not exactly looking at the base of the cylinder. It automatically opens the Motion panel. So the Motion panel opens on the right hand side in the Command panel. If we scroll down you have a Select Look At Axis. Does everybody see that? Yes? That's Select Look At Axis will determine what axis is looking at that object. So in this case, select Z and that will reorient it. If for some reason, you're doing this and it's backwards, like the Z is go in the opposite direction, you can flip it. That will happen occasionally if you build something or you bring something in from another program. And the reason why I use dummies on a lot of stuff is if I bring something in from Inventor or Revit or whatever, the orientation of the axis is not always the way I want it. And I'll create a dummy object because that gives me the axis the way I need it. And then I just link whatever objects to that dummy object.

So dummy objects are your friends. They're not really that dumb. Trying to figure out why they're called dummies. Yes?

AUDIENCE: Is there a reason that you're using dummy objects instead of point helpers?

STEVEN SCHAIN: You know what? I use point helpers a lot. I did find that for some reason-- and I have to talk to some of the Autodesk guys-- and it only happens when I do wiring. When I wire a point helper as opposed to a dummy object in a hierarchy, it does not work. So I was doing the same wiring here but I had an assembly that I was doing. And I put a point helper in wired up just like normal outside of the hierarchy, works just fine. Put it in the hierarchy, didn't work. Did the same thing with a dummy object, no problem.

AUDIENCE: It goes on.

STEVEN SCHAIN: Yeah. So I repeated the same thing thinking, maybe I did something wrong, but, no it was same thing. Different file, totally different setup. But for the most part, I will use point helpers because I can see the orientation. It doesn't really matter. I think that's personal preference at that point. But yeah, that whole rotation thing I got to find out about.

So the next thing is we're not going to select the dummy here, we're going to select the piston up here. Or sorry we're going to select the dummy. No, we have the dummy. No, we're going to select this one. Sorry. I'm getting way ahead of myself. Yes?

AUDIENCE: Going back to that [INAUDIBLE].

STEVEN SCHAIN: Yes.

AUDIENCE: Does it mean that [INAUDIBLE]?

STEVEN SCHAIN: It's the locals z-axis for the object. So think of it this way. Think of you have a tin can on a piece of string. So the string is your look at. The tin can, you have the z-axis running through the center of the can. It's based on the local z-axis for that object. So anywhere the look at object moves, the object itself is going to look. It's based on that locals local x, y, and z. So it's not world coordinates it's local. Yeah. So we'll select the piston here. Go back to Animation, Constraints, Look At Constraint. And here we're going to pick this look at. So it's that other dummy object. And this is why we're doing this. We couldn't look at this object, because this object is looking somewhere else.

So we picked the smaller look at dummy. And we do the same thing, just come down. Say you're look at access to z and that sets up your look at. If you want to test it out you can come down here and just pick this bone, and rotate that bone. And you'll see that now works.

So select and rotate, pick that second bone there, and rotating that bone around. You'll see that it is now rigged and it works the way you needed to work.

So any questions? Yes?

AUDIENCE: [INAUDIBLE]

STEVEN SCHAIN: Let's see.

Oh. Yeah, you want to select-- see that little bone there?

AUDIENCE: This one?

STEVEN SCHAIN: Yeah, so just undo.

And then click on that.

AUDIENCE: This one?

STEVEN SCHAIN: Yeah. No. There you go. Yep.

Yeah, there you go. So rotate around the y.

AUDIENCE: Around the y?

STEVEN SCHAIN: Yep. That axis. Oh, you don't have your-- so pan down. Select this cylinder. Wait. Hit Q. That'll get you into Select, select that cylinder. And then come up to Select and Link. And click and drag it to that dummy object. Yeah. There you go. Now, select that again. So press Q. Select that. And then rotate that around the y-axis. So E. And then see the yellow ring there? There you go.

AUDIENCE: OK. Thank you.

STEVEN SCHAIN: You're welcome. So if you're not familiar with keyboard shortcuts, Q is the ultimate keyboard shortcut. Gets you out of move, rotate, scale pretty much anything that will get you into trouble. So just press Q and it gets you out. And if you want to go through these when you get back to the office, all this stuff, the data set, all the other files are available through the website.

So any questions? Yes?

AUDIENCE: [INAUDIBLE]

STEVEN SCHAIN: I break it down by what needs to move and how it needs to move. So like with this rig, I looked at where are all my pivot points, what's attached to that pivot point, does it have to move, rotate, scale? Do I need to wire something? So I look at every pivot point and I try and figure out A, what that point is doing. Then I work backwards from there and figure out how do I want to animate it. So does it need to be animated at all? Can it just be rigged? So you'll see in the last thing we do is, we animate the rig by adjusting some sliders. So essentially, you're not animating anything that's on the rig itself. You're just animating the sliders. So that's the way I like to do sliders. I generally would do the sliders in a dialog box and set it up differently. But for this class, it's just easier to have them on screen. Because they could fill up your screen really quickly. Yes?

AUDIENCE: How do you lift the rotation of that value to [INAUDIBLE]?

STEVEN SCHAIN: You can do that through the bone dialog. There's ways of limiting it. Well, I'll show you. So if I select a bone here and I come over to the Motion panel, I have my IK and I have my rotation joint. And I can limit these. So you'll see here I have the ability to limit them. So it won't limit if I'm actually just rotating. It only limits it if I'm using it in an IK chain. So you have to be careful you can set a limit as a controller. So there are what are known as limit controllers. So I don't know how familiar you are with 3ds Max. So you can assign a limit controller and that will actually allow you to limit the values between two values.

So with bones you have two options. If it's in an IK chain, which is what we're going to do next, you can set the limits on the bones themselves and they'll respect that. If you are not and you're actually using forward kinematics, just animating the bone itself, then you can apply a limit controller and limit the number. So you can just say, I only want this value to go between 50 and 500. So you can limit that. So what we're going to look at next is we're going to look at linking and configuring a scissor joint. Let's see where we're at. We got a half hour.

So let's go ahead and open a new file. Don't save. We're going to use excavator_rig01.

Can everybody see that well? Yes? No?

Sometimes I wonder how the dark scheme looks on these projectors versus the lighter scheme. So we're going to create a bone chain and then we're going to link a couple things to the bone chain and create an IK. So we're going to come over to the Create panel, and bone chain is a system. We're going to click Bones. And what we're going to do is we're going to click sort of at the center of this point right here to create the first one. Going to click about right there for the second one. And then we're going to click about the center of that for the third one. And then we're not going to click again. We're going to right click to end the bone creation.

That is going to give us our bone chain.

And we'll right click again to get out of creation mode. Yes?

AUDIENCE: So what is the point of the bone chain if you have to break the geometry to get in there?

STEVEN SCHAIN: Well, that the geometry actually is not rigged yet. So the geometry right now is just sitting there. If I move this it's just off by itself.

AUDIENCE: OK. I guess the armature would be kind of poor.

STEVEN SCHAIN: Right so what this is, this is a subset of that armature that when the bucket rotates out, I want the scissors to close and open. Right now it's not going to do that. They're linked but what would happen is they're just sort of passed through each other. When the bucket opens this would just sort of go like that through it. I want it so that they pivot like that and open like a scissor joint.

AUDIENCE: The bone will do that?

STEVEN SCHAIN: The bone will allow us to assign an IK chain and that will give us the ability like-- IK, there's two ways of animating there's inverse kinematics and forward kinematics. Forward kinematics is sort of traditional animation. If you want to get your hand from here out to here you have two ways of doing it. Forward kinematics is, I rotate this, I rotate that, I moved that up again, I rotate that down. So I've now animated two objects. Inverse kinematics says, take the end of this hand and move it over here, everything else goes along with it. So it makes rigging a lot easier because then you're just moving this one part and everything follows. And by using the bones it allows you to control the inverse kinematics with a little more control.