Documentation Update (Unity-Technologies#1339)

* Documentation Update

* addressed comments

* new images for the recorder

* Improvements to the docs

* Address the comments

* Core_ML typo

* Updated the links to inference repo

* Put back Inference-Engine.md

* fix typos : brain

* Readd deleted file

* fix typos

* Addressed comments

Author: vincentpierre

README.md

@@ -38,7 +38,7 @@ developer communities.
 * For more information, in addition to installation and usage instructions, see
   our [documentation home](docs/Readme.md).
 * If you are a researcher interested in a discussion of Unity as an AI platform, see a pre-print of our [reference paper on Unity and the ML-Agents Toolkit](https://arxiv.org/abs/1809.02627). Also, see below for instructions on citing this paper.
-* If you have used a version of the ML-Agents toolkit prior to v0.6, we strongly
+* If you have used an earlier version of the ML-Agents toolkit, we strongly
   recommend our [guide on migrating from earlier versions](docs/Migrating.md).
 
 ## Additional Resources

docs/Basic-Guide.md

@@ -10,10 +10,8 @@ the basic concepts of Unity.
 
 ## Setting up the ML-Agents Toolkit within Unity
 
-In order to use the ML-Agents toolkit within Unity, you need to change some
-Unity settings first. You will also need to have appropriate inference backends
-installed in order to run your models inside of Unity. See [here](Inference-Engine.md)
-for more information.
+In order to use the ML-Agents toolkit within Unity, you first need to change a few
+Unity settings. 
 
 1. Launch Unity
 2. On the Projects dialog, choose the **Open** option at the top of the window.
@@ -22,26 +20,43 @@ for more information.
 4. Go to **Edit** > **Project Settings** > **Player**
 5. For **each** of the platforms you target (**PC, Mac and Linux Standalone**,
    **iOS** or **Android**):
-    1. Option the **Other Settings** section.
+    1. Expand the **Other Settings** section.
     2. Select **Scripting Runtime Version** to **Experimental (.NET 4.6
        Equivalent or .NET 4.x Equivalent)**
 6. Go to **File** > **Save Project**
 
+## Setting up the Inference Engine
+
+We provide pre-trained models for all the agents in all our demo environments. 
+To be able to run those models, you'll first need to set-up the Inference 
+Engine. The Inference Engine is a general API to
+run neural network models in Unity that leverages existing inference libraries such 
+as TensorFlowSharp and Apple's Core ML. Since the ML-Agents Toolkit uses TensorFlow 
+for training neural network models, the output model format is TensorFlow and 
+the model files include a `.tf` extension. Consequently, you need to install 
+the TensorFlowSharp backend to be able to run these models within the Unity 
+Editor. You can find instructions 
+on how to install the TensorFlowSharp backend [here](Inference-Engine.md).
+Once the backend is installed, you will need to reimport the models : Right click
+on the `.tf` model and select `Reimport`.
+
+
 ## Running a Pre-trained Model
 
 1. In the **Project** window, go to `Assets/ML-Agents/Examples/3DBall/Scenes` folder
    and open the `3DBall` scene file.
 2. In the **Project** window, go to `Assets/ML-Agents/Examples/3DBall/Prefabs` folder
    and select the `Game/Platform` prefab.
-3. In the `Ball 3D Agent` Component: Drag the **3DBallLearning** located into 
+3. In the `Ball 3D Agent` Component: Drag the **3DBallLearning** Brain located in 
    `Assets/ML-Agents/Examples/3DBall/Brains` into the `Brain` property of 
    the `Ball 3D Agent`.
 4. Make sure that all of the Agents in the Scene now have **3DBallLearning** as `Brain`.
-   __Note__ : You can modify multiple game objects in a scene by selecting them all at once using the search bar in the Scene Hierarchy. 
+   __Note__ : You can modify multiple game objects in a scene by selecting them all at 
+   once using the search bar in the Scene Hierarchy. 
 5. In the **Project** window, locate the `Assets/ML-Agents/Examples/3DBall/TFModels` 
    folder.
-6. Drag the `3DBall` model file from the `Assets/ML-Agents/Examples/3DBall/TFModels` 
-   folder to the **Model** field of the **3DBallLearning**.
+6. Drag the `3DBallLearning` model file from the `Assets/ML-Agents/Examples/3DBall/TFModels` 
+   folder to the **Model** field of the **3DBallLearning** Brain.
 7. Click the **Play** button and you will see the platforms balance the balls
    using the pretrained model.
 
@@ -63,15 +78,26 @@ More information and documentation is provided in the
 
 ### Adding a Brain to the training session
 
-Since we are going to build this environment to conduct training, we need to add 
-the Brain to the training session. This allows the Agents linked to that Brain
-to communicate with the external training process when making their decisions.
-
-1. Assign the **3DBallLearning** to the agents you would like to train and the **3DBallPlayer** Brain to the agents you want to control manually. 
-   __Note:__ You can only perform training with an `Learning Brain`.
+To set up the environment for training, you will need to specify which agents are contributing
+to the training and which Brain is being trained. You can only perform training with
+a `Learning Brain`.
+
+1. Assign the **3DBallLearning** Brain to the agents you would like to train.  
+   __Note:__ You can assign the same Brain to multiple agents at once : To do so, you can
+   use the prefab system. When an agent is created from a prefab, modifying the prefab 
+   will modify the agent as well. If the agent does not synchronize with the prefab, you
+   can hit the Revert button on top of the Inspector.
+   Alternatively, you can select multiple agents in the scene and modify their `Brain`
+   property all at once.
 2. Select the **Ball3DAcademy** GameObject and make sure the **3DBallLearning** Brain
    is in the Broadcast Hub. In order to train, you need to toggle the
    `Control` checkbox.
+   
+__Note:__ Assigning a Brain to an agent (dragging a Brain into the `Brain` property of 
+the agent) means that the Brain will be making decision for that agent. Whereas dragging
+a Brain into the Broadcast Hub means that the Brain will be exposed to the Python process.
+The `Control` checkbox means that in addition to being exposed to Python, the Brain will
+be controlled by the Python process (required for training).
 
 ![Set Brain to External](images/mlagents-SetBrainToTrain.png)
 

docs/FAQ.md

@@ -15,7 +15,7 @@ Unity](Installation.md#setting-up-ml-agent-within-unity) for solution.
 
 ## Cannot drag Model into Learning Brain
 
-You migh not have the appropriate backend required to import the model. Refer to the 
+You might not have the appropriate backend required to import the model. Refer to the 
 [Inference Engine](Inference-Engine.md) for more information on how to import backends
 and reimport the asset.
 

docs/Getting-Started-with-Balance-Ball.md

@@ -53,10 +53,10 @@ to speed up training since all twelve agents contribute to training in parallel.
 The Academy object for the scene is placed on the Ball3DAcademy GameObject. When
 you look at an Academy component in the inspector, you can see several
 properties that control how the environment works. 
-The **Broadcast Hub** keeps track of which brains will send data during training,
-If a brain is added to the hub, his data will be sent to the external training
+The **Broadcast Hub** keeps track of which Brains will send data during training,
+If a Brain is added to the hub, his data will be sent to the external training
 process. If the `Control` checkbox is checked, the training process will be able to
-control the agents linked to the brain to train them.
+control the agents linked to the Brain to train them.
 The **Training** and **Inference Configuration** properties 
 set the graphics and timescale properties for the Unity application. 
 The Academy uses the **Training Configuration**  during training and the
@@ -89,16 +89,16 @@ environment around the Agents.
 ### Brain
 
 Brains are assets that exist in your project folder. The Ball3DAgents are connected
-to a brain, for example : the **3DBallLearning**.
+to a Brain, for example : the **3DBallLearning**.
 A Brain doesn't store any information about an Agent, it just
 routes the Agent's collected observations to the decision making process and
 returns the chosen action to the Agent. Thus, all Agents can share the same
 Brain, but act independently. The Brain settings tell you quite a bit about how
 an Agent works.
 
-You can create brain objects by selecting `Assets -> 
-Create -> ML-Agents -> Brain`. There are 3 kinds of brains :
-The **Learning Brain** is a brain that uses a Neural Network to take decisions.
+You can create Brain objects by selecting `Assets -> 
+Create -> ML-Agents -> Brain`. There are 3 kinds of Brains :
+The **Learning Brain** is a Brain that uses a Neural Network to take decisions.
 When the Brain is checked as `Control` in the Academy **Broadcast Hub**, the 
 external process will be taking decisions for the agents
 and generate a neural network when the training is over. You can also use the
@@ -225,7 +225,7 @@ environment first.
 The `--train` flag tells the ML-Agents toolkit to run in training mode.
 
 **Note**: You can train using an executable rather than the Editor. To do so,
-follow the intructions in
+follow the instructions in
 [Using an Executable](Learning-Environment-Executable.md).
 
 ### Observing Training Progress

docs/Learning-Environment-Best-Practices.md

@@ -3,7 +3,7 @@
 ## General
 
 * It is often helpful to start with the simplest version of the problem, to
-  ensure the agent can learn it. From there increase complexity over time. This
+  ensure the agent can learn it. From there, increase complexity over time. This
   can either be done manually, or via Curriculum Learning, where a set of
   lessons which progressively increase in difficulty are presented to the agent
   ([learn more here](Training-Curriculum-Learning.md)).

docs/Learning-Environment-Create-New.md

@@ -158,11 +158,11 @@ in the Inspector window.
 ## Add Brains
 
 The Brain object encapsulates the decision making process. An Agent sends its
-observations to its Brain and expects a decision in return. The type of the brain
+observations to its Brain and expects a decision in return. The type of the Brain
 (Learning, Heuristic or player) determines how the Brain makes decisions. 
 To create the Brain:
 
-1. Go to `Assets -> Create -> ML-Agents` and select the type of brain you want to
+1. Go to `Assets -> Create -> ML-Agents` and select the type of Brain you want to
    create. In this tutorial, we will create a **Learning Brain** and 
    a **Player Brain**.
 2. Name them `RollerBallBrain` and `RollerBallPlayer` respectively.
@@ -467,7 +467,7 @@ Brain asset to the Agent, changing some of the Agent Components properties, and
 setting the Brain properties so that they are compatible with our Agent code.
 
 1. In the Academy Inspector, add the `RollerBallBrain` and `RollerBallPlayer`
-   brains to the **Broadcast Hub**.
+   Brains to the **Broadcast Hub**.
 2. Select the RollerAgent GameObject to show its properties in the Inspector
    window.
 3. Drag the Brain `RollerBallPlayer` from the Project window to the 
@@ -479,7 +479,7 @@ setting the Brain properties so that they are compatible with our Agent code.
 Also, drag the Target GameObject from the Hierarchy window to the RollerAgent
 Target field.
 
-Finally, select the the `RollerBallBrain` and `RollerBallPlayer` brains assets
+Finally, select the the `RollerBallBrain` and `RollerBallPlayer` Brain assets
 so that you can edit their properties in the Inspector window. Set the following 
 properties on both of them:
 
@@ -492,16 +492,16 @@ Now you are ready to test the environment before training.
 ## Testing the Environment
 
 It is always a good idea to test your environment manually before embarking on
-an extended training run. The reason we have created the `RollerBallPlayer` brain
+an extended training run. The reason we have created the `RollerBallPlayer` Brain
 is so that we can control the Agent using direct keyboard
 control. But first, you need to define the keyboard to action mapping. Although
 the RollerAgent only has an `Action Size` of two, we will use one key to specify
 positive values and one to specify negative values for each action, for a total
 of four keys.
 
-1. Select the `RollerBallPlayer` brain to view its properties in the Inspector.
+1. Select the `RollerBallPlayer` Brain to view its properties in the Inspector.
 2. Expand the **Continuous Player Actions** dictionary (only visible when using
-   a player brain).
+   a **PlayerBrain**).
 3. Set **Size** to 4.
 4. Set the following mappings:
 

docs/Learning-Environment-Design-Academy.md

@@ -50,9 +50,9 @@ logic for creating them in the `AcademyStep()` function.
 ## Academy Properties
 
 ![Academy Inspector](images/academy.png)
-* `Broadcast Hub` - Gathers the brains that will communicate with the external 
-  process. Any brain added to the Broadcast Hub will be visible from the external
-  process. In addition, if the checkbox `Control` is checked, the brain will be 
+* `Broadcast Hub` - Gathers the Brains that will communicate with the external 
+  process. Any Brain added to the Broadcast Hub will be visible from the external
+  process. In addition, if the checkbox `Control` is checked, the Brain will be 
   controllable from the external process and will thus be trainable.
 * `Max Steps` - Total number of steps per-episode. `0` corresponds to episodes
   without a maximum number of steps. Once the step counter reaches maximum, the

docs/Learning-Environment-Design-Agents.md

@@ -19,7 +19,7 @@ The Brain class abstracts out the decision making logic from the Agent itself so
 that you can use the same Brain in multiple Agents. How a Brain makes its
 decisions depends on the kind of Brain it is. A Player Brain allows you
 to directly control the agent. A Heuristic Brain allows you to create a 
-decision script to control the agent with a set of rules. These two brains
+decision script to control the agent with a set of rules. These two Brains
 do not involve neural networks but they can be useful for debugging. The
 Learning Brain allows you to train and use neural network models for
 your Agents. See [Brains](Learning-Environment-Design-Brains.md).

docs/Learning-Environment-Design-Brains.md

@@ -5,9 +5,9 @@ assigned a Brain, but you can use the same Brain with more than one Agent. You
 can also create several Brains, attach each of the Brain to one or more than one
 Agent.
 
-There are 3 kinds of brains you can use:
+There are 3 kinds of Brains you can use:
 
-* [Learning](Learning-Environment-Learning-Brains.md) – Use a
+* [Learning](Learning-Environment-Design-Learning-Brains.md) – Use a
   **LearningBrain** to make use of a trained model or train a new model.
 * [Heuristic](Learning-Environment-Design-Heuristic-Brains.md) – Use a
   **HeuristicBrain** to hand-code the Agent's logic by extending the Decision class.
@@ -55,7 +55,7 @@ to a Brain component:
     * `Action Descriptions` - A list of strings used to name the available
       actions for the Brain.
 
-The other properties of the brain depend on the type of Brain you are using.
+The other properties of the Brain depend on the type of Brain you are using.
 
 ## Using the Broadcast Feature
 

docs/Learning-Environment-Design.md

@@ -72,7 +72,7 @@ information.
 
 To train and use the ML-Agents toolkit in a Unity scene, the scene must contain
 a single Academy subclass and as many Agent subclasses
-as you need. The brain assets are present in the project and should be grouped 
+as you need. The Brain assets are present in the project and should be grouped 
 together and named according to the type of agents they are compatible with.
 Agent instances should be attached to the GameObject representing that Agent.
 
@@ -114,18 +114,18 @@ the Academy properties and their uses.
 
 The Brain encapsulates the decision making process. Every Agent must be
 assigned a Brain, but you can use the same Brain with more than one Agent.
-__Note__:You can assign the same brain to multiple agents by using prefabs
-or by selecting all the agents you want to attach the brain to using the 
+__Note__:You can assign the same Brain to multiple agents by using prefabs
+or by selecting all the agents you want to attach the Brain to using the 
 search bar on top of the Scene Hierarchy window.
 
 To Create a Brain, go to `Assets -> Create -> Ml-Agents` and select the 
-type of brain you want to use. During training, use a **Learning Brain** 
+type of Brain you want to use. During training, use a **Learning Brain** 
 and drag it into the Academy's `Broadcast Hub` with the `Control` checkbox checked.
 When you want to use the trained model, import the model file into the Unity
 project, add it to the **Model** property of the **Learning Brain** and uncheck
 the `Control` checkbox of the `Broadcast Hub`. See
 [Brains](Learning-Environment-Design-Brains.md) for details on using the
-different types of Brains. You can create new kinds of brains if the three
+different types of Brains. You can create new kinds of Brains if the three
 built-in don't do what you need.
 
 The Brain class has several important properties that you can set using the