# Train Engine Tutorial

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Train Engine Part 1 | Train Engine Part 2

With the rigging parameters explained in the Train Overview video, Rich goes about explaining his 'best-practices' for organization and naming in this video. With the use of his 'Rig Sketch' technique he explains his thought process to resolve the problems at hand and then set out applying the tools modo has available to create the rig for the train. User can follow along by opening the models directly from the resources tab below or simply watch and learn as a master rigger teaches his craft.

Users can jump ahead to a specific section by using the Chapter selection widget on the right side of the player or by directly clicking any of the Chapter Title links below.

Tab | Time | Chapter | Description
1 | 00:00:08 | Locators & Setup | Setting up of Locators and planning out colors.
2 | 00:17:43 | User Channels | Creation of the necessary user channels.
3 | 00:23:38 | Building Mods | Adding the necessary modifiers to the scene.
4 | 00:28:05 | Connecting Riders | Conecting the 'riders' to the curve and hooking up the channels in the Schematic view.
5 | 00:49:36 | Connecting Mesh | Attaching the train elements to the rigged locators.
6 | 00:54:46 | Attaching Wheels | Attaching the wheels to the train and making them roll.
5 | 01:10:58 | Train Rig UI | Planning and executing the rig UI to control the train with a Rig Sketch.
6 | 01:16:18 | Prototype | Rig UI prototype proof-of-concept.
7 | 01:24:08 | Rig Control | Building up the rig control assembly.
8 | 01:45:32 | Assembly Preset | Exporting the rig controller into a preset asset for later use.
9 | 01:49:09 | Applying Preset | Applying the assembly preset to the locomotive engine.
10 | 01:58:19 | Lock Selections | Controlling what the end user can and cannot select.
| 02:02:30 | Total Video Time |

Frequently Asked Questions--

Q.) Whenever he trying to change a color, the color dialog appears out of frame and he has to drag it back, its annoying, why doesn't he just move it to the center?

> A.) It's all OSX's fault, you would think if you moved it into place and then closed it, it would remember its last position but no, it doesnt. It's distracting we know, but there's no way to change it.

Q.) Wait a minute, he mentions a truck as something we are going to do in the training, where is that?

> A.) When Rich embarked on building the tutorial section he originally planned to also rig a dump truck. As things progressed it became clear that the train, hopper car and crane were more than enough to cover what he wanted, so it was punted.

Q.) Sometimes when I rotate something in item mode it will also push values into the position channels, why does this happen?

> A.) This is because modo allows for you to have your "action center" placed independently from the actual center point of the item you are trying to rotate. To help prevent getting values you don't want set your action center to either "Local" or "Pivot". This will force the manipulator to be set right at your item's rotational center. For more information check out the Action Centers section in the Foundation section.

Q.) Wait, he called the group locator "SuspensionRigChans" but its called "RigChans" in the files I have, why?

> A.) After rigging the Hopper Car and the Crane he realized that chaining the name to simply "RigChans" made more sense so he went in and changed it. He didn't want to record the lessons over for just a simple name change, He mentions how lazy he is in the recording, here is proof :)

Q.) What does he mean by "Parametric Distance"?

> A.) A curve's length is defined as 0 to 1, 0 being the beginning and 1 being the end. No matter how long it is in your 3D scene its length is always defined by this "Parameter". Using some modifiers its possible to convert this 0 to 1 value into an actual measure of distance. So the "Parametric Distance" is the range in between 0 to 1 that translates into the actual length you may be trying to find.

Q.) Gah! he's using a lot of math, I hate math! Do I have to understand a lot of math to rig?

> A.) Welcome to rigging, you will be forced to use both sides of your brain to be an effective rigger. There are of course different levels of math and art you will need to know depending on the task at hand, and modo provides a lot of modifiers to help with the math side of things. You will need to have a basic grasp of both though, its just part of the process.

Q.) He changed the Locomotive color to make it "easier" to read, but I it actually looks more difficult to read to me, whats up with that?

> A.) It is actually easier to read on the screen but for some reason in the recording it looks worse. You will just need to load it up live in modo to judge for yourself and change it if you feel the need.

Q.) He talks about clicking on a locator and getting the channel haul UI to appear, what is that?

> A.) That is the ability to define a command on a locator that will take any user channels attached to that locator and automatically select them and turn on the channel haul too. You do this by adding the "item.channelHaul" command into command line in the assembly sub tab for the locator. For more info check out Assembly and Rig UI in the Foundation section.

Q.) So I still don't understand why we need a rig control item, can you break it down for me again?

> A.) The reason for the rig control item, in its simplest form, is to trick modo into giving us manipulators that we can use to control something in our rigs. The big win is that we do not have to worry about the item itself being moved or adjusted. This means that we can separate where the rig control item is attached into our rig from what it will control. Giving us a lot of control and flexibility in how we present rig controls to our users.

Q.) He keeps adding in modifiers through the menu, can't you simply duplicate it instead?

> A.) You can, but when you do the new duplicate will get added under the scene root and not right where the original is located. You can just drag them out from under the scene item and put them in the item list where you want but its a pain. It's a known issue with modo and to help with clarity in the training I decided to just add them by hand each time.

Q.) When he opens up the Assembly Group for the rig control item, it's a big mess, why?

> A.) When things are added to an assembly group by default they get added in the center of the workspace. So when you save an assembly preset everything gets added into the assembly group at once, all in the center. He could have taken the time to organize the assembly group's work space but as he keeps mentioning over and over, he's lazy :)

Q.) He just clicked on the yellow circle in the schematic view to bring up the other nodes connected, how did he do that?

> A.) If you middle mouse click on any yellow connection dot in the schematic it will load the nodes that are connected. Check out the Schematic section of the Foundation for more information.

Q.) He mentioned math "nodes" aren't they really math "modifiers" ?

> A.) Yes. The terms "modifiers" and "nodes" will be used interchangeably during the training but they are the same thing in modo.

Q.) He called the groups "Control" groups, but I only see Assembly or Item groups, am I missing something?

> A.) Nope. The term control is being used to describe what needs to happen, Item groups is what will actually be used to "control" the selection and locking for the rig.

Resources--

Links to the modo in-line help system
Docs: Locator Display
Docs: Action Centers
Docs: Statistic and Info Panel
Docs: User Channels
Docs: Schematic
Docs: Direction Constraint
Docs: Assembly Tab
Docs: Groups

Links to other pages in this training
Training: Locator Display
Training: Align Set Drop Tools
Training: Action Centers
Training: Channels
Training: Schematic View
Training: Constraints
Training: Assembly and RigUI
Training: Transform Items
Training: Modifiers
Training: Assembly Groups
Training: Groups

File--

Links to the modo scenes used in the video
(click to open in modo)
File: Locomotive_03_Rig_01.lxo
File: Locomotive_03_Rig_02.lxo
File: Locomotive_05_RigControl_01.lxo
File: Locomotive_05_RigControl_02.lxo
File: Locomotive_05_RigControl_03.lxo
File: Locomotive_06_Complete_01.lxo
File: Locomotive_06_Complete_02.lxo

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