# Modifiers

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Modifiers | Modifiers in Action

Animation modifiers provide users a way to procedurally control elements within a scene without requiring direct keyframe values. Useful functions such as keeping elements centered between others, or forcing an element to always face toward the camera, are options possible with modifiers. The 'Modifiers' page covers each modifier and its application and use, the 'Modifiers in Action' page shows some actual usage scenarios of Modifiers (selected above) where Rich builds a real working clock based on the timeline, with some additional controls and a real working combination lock, demonstrating the thought process of solving complex rigging scenarios with linked modifiers producing programming like logic.

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 | 00:01:22 | What Is Modifier | Definition of what Modifiers are in modo.
2 | 00:09:17 | Modifiers Intro | Introduction of how to use and apply Modifiers.
3 | 00:10:14 | Channel Modifiers | Modifiers that affect channels.
4 | 00:26:09 | Conditional | Explanation of the Logic operators.
5 | 00:40:08 | Constraint | Overview of Constraints (covered in 'Constraints' section).
6 | 00:40:51 | Time | Linking Locators to other items in the scene for easy rig referencing.
7 | 00:43:08 | Measure | Explanation of the Measuring Modifiers.
8 | 00:47:24 | Other Modifiers | Coverage for miscellaneous Modifiers.
9 | 01:03:40 | Math Modifiers | Explanation of the Math operation Modifiers.
10 | 01:31:16 | Matrix | Explanation of the Matrix Modifiers.
11 | 01:47:11 | Vector | Explanation of the Vector Modifiers.
| 01:59:50 | Total Video Time |

Frequently Asked Questions--

Q.) Why are some channel modifier's channel inputs (or outputs) unidirectional... meaning you can only make a connection either just in or just out ?

> A.) There is no hard fast rule on this... as some channels that do not allow output connections could with no ill effect. Input channels can be more strait forward at times, like it doesn't make sense to allow an input connection to an output channel. Just be aware of which channels allow for what types of connections before you plan your modifier usage and you will be fine.

Q.) Why does modo have all modifiers positioned under the Scene item even if they have been parented under an item in the item list?

> A.) This allows modo to have a complete view of all the modifiers that are being considered or executed in the scene. When you attached a modifier to an item, you are really just making an "alias" to the real modifier that is under the scene item. That is why if you select it in the scene list it will also select it if you have it parented under an item.

Q.) Why does the Schematic allow you to create Modifiers at the scene level and the "Add Channel Modifier" panel does not?

> A.) This is because in the Schematic you may be building an Assembly Group, where you may not want the Modifiers that define its functionality to live anywhere but in that group (from the Item List's perspective). The Schematic View, actually being just a modified Assembly Group, it makes sense that you would have the 'Add Modifier' button always active. Check out the Assembly Group section for more info.

Channel

Q.) Why don't all the channels come in with a modifier when it is added to the schematic?

> A.) Modo tries to only put the channels that it feels will be most important when you first add any items into the schematic, not just modifiers. In some cases, like with mesh items, if you added all the possible channels the node would be ginormous looking in the schematic. Just always have the channels list nearby when adding anything into the schematic to see what channels you might still need.

Q.) Why does the Channel Relationship have its own special UI and other modifiers do not?

> A.) This was developed during 401 when the only way to link channels together was through the Channel Links panel. Without this UI and without a schematic view it would have been much harder to see how channels were feeding into and out of the Channel Relationship.

Q.) It looked like he had trouble adjusting the first key on the "Value" channel, what was going on there?

> A.) If you look back you'll notice that the key was purple, which means he had broken the tangent (see the Graph Editor Section) and when you do that you will sometimes lose the ability to move that handle. If he would have reconnected the tangents it would have allowed him to move the handle the way he wanted.

Conditional

Q.) Man I am soooo tired of him saying something is "handy", how about you?

> A.) Yes... yes we are.

Q.) Why is 180 mm displayed as .18 in all the modifiers?

> A.) Modifiers display everything based on modo's default unit, which is a meter. So .18 meters is the same as 180 mm.

Q.) He keeps pulling the connections off the node they are feeding into, is there another way to remove the connections?

> A.) Yes. If you select the connection and hit the "delete" key it will remove the connection. Checkout the Schematic section in the training for more info.

Q.) When he showed the "A AND B are True" conditional, why didn't the modifier round the values down when they went below .5, giving it a "False"?

> A.) That is because the input really only accept integer values, so it will stay it whatever its state is until a whole number is input. To learn a bit more about floating point vs. integer (whole) numbers check out the Channels section.

Constraints

Q.) Wait, constraints are modifiers too?

> A.) They are one and the same. Constraints are really the backbone of most rigging tasks so modo presents them with a more full featured GUI to apply them... but they are just modifiers. If you wanted to, you could wire up all the channels for each by hand and get the same results as you would by using the buttons in the UI. Check out the Constraints section in the training for more info.

Measure

Q.) He keeps saying "Martix4D" but I only see "Matrix4" is there a difference?

> A.) No. The "D" is just his way of saying "Dimensional" as in a 4 dimensional or "4x4" matrix. Just ignore that when you hear it.

Other

Q.) Will he REALLY give me a cookie if I use Simple Kinematics for production?

> A.) No. He's a tease that way... though it would be cool if you did use it for something that made you money. Then you could buy your own cookie... and maybe share it with him :)

Q.) He plugged the percentage output from the Revolve Modifier into the "offset" of the path constraint, shouldn't he have put it into the percentage?

> A.) Good Catch! Yes in a real world situation its better to use the percentage output. Offset is really used to set a series of items at different starting points along the curve so you can use a single driving channel to move the group along the curve together. Check out the Constraints section for more info.

Math

Q.) He really destroys the pronunciation of "Modulo" doesn't he?

> A.) Yes he sure does. It's even better when it's the modifier that he says you may never use, then he puts it to use in the 'Modifiers In Action' section to solve a pretty big problem. Check that section out to see how he uses it.

Q.) Why don't we see the input values show up in the channel list after connecting a channel to them?

> A.) It's because the connected value is different from the modifier's internal value for that channel. This is designed behavior that I wish were changed personally, as it can really confuse people that do not know what to look for. Just be aware of this as you starting building your networks and backtrack through your links to find the values feeding into the channel in question.

Q.) He mentions that with 'Subtract Multiple' the order you plug the inputs in matters as to how it evaluates; is there anyway to see this order?

> A.) Yes. If you go to the channel list and you click the "+" next to the "inputs" channel you will see a list of all the inputs. That shows you the order of how the channels evaluate, from the top to bottom.

Q.) Is there a way to reorder the inputs into the node without removing them and reconnecting again?

> A.) No. I hope that someday we will be able to reorder them in the channel list, but for now, removing and reconnecting is the only way.

Matrix

Q.) Trinity?

> A.) Whoa.

Vector

Q.) What's your Vector Victor?

> A.) Roger Rodger.

Resources--

Links to the modo in-line help system
Docs: Track View (aka Dope Sheet)
Docs: Graph Editor

Links to other pages in this training
Training: Keyframes Dope Sheet
Training: Channels
Training: Modifiers (Channel Relationship)
Training: General UI
Training: Modifiers in Action (Clock)

File--

Links to the modo scenes used in the video
(click to open in modo)
File: Modifers_01.lxo
File: Modifers_02.lxo

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