To celebrate the fact that we now have over 3000 members on the MCG Facebook page, and to make up for the long periods without posts I wanted to share a new set of MCG tools and compounds: you can download the MCG Sample Pack 2 here.
Before installing the Sample Pack I recommend you first backup your entire MCG user folder (%userprofile%/Autodesk/3ds Max 2016/Max Creation Graph). You can then unzip the file contents directly into your MCG user folder. This package includes all of the tools and compounds from the original sample pack and includes updates to the MCG curvature sample, so overwriting existing files should be fine, unless of course you made your own modifications to these tools or compounds, which is why I strongly recommend backing up your folder!
At the core of this sample pack is a set of modifiers called the Flux toolkit for performing object cloning, placement, and creating animations. These minitools work together to enable users to create sophisticated effects as demonstrated in this video:
Even if you don't find the Flux toolkit directly useful it does demonstrate a very powerful workflow for MCG tools: using Map Channels to share data between tools. It also serves to showcase and test a large number of new compounds the address common challenges that arise when writing MCG tools. For example orienting objects towards another, generating random points on a surface, interpolating positions and tangents along a spline, and so forth.
How Flux Works
Flux works by storing transform matrices in a map channel to represent the position, rotation, and scale of each cloned object. You place a Flux initializer modifier (e.g. Flux_Initialize_Vertices) on an object to initialize the map channel. Next you place the Flux modifiers you want. Finally you add a Flux_Evaluate modifier on top to generate clone a mesh at each of the matrices.
Things get very interesting when you use the Flux blend modifiers (e.g. Flux_Blend_Falloff) to interpolate between the top and previous Flux effect. This is where the “combine effect” checkbox can be useful. Most Flux effects also have a "strength" value that allows you to control an interpolation between the Flux effect (or combined effect) and the previous effect. Flux effects can also be copied to and from other map channels to enable your to reuse intermediate effects (e.g. using Flux_Store_Data and Flux_Load_Data).
Flux Modifiers
The following is a list of the Flux modifiers
Flux Modifier

Modifier Type

Description

Flux Align Axis

Transform

Orients one axis of each matrix

Flux Blend Falloff

Blend

The effect is applied to matrices in a specified part of the array, with a falloff

Flux Blend Offset

Blend

The effect strength is applied to matrices with before the specific location in the array.

Flux Blend Randomly

Blend

The effect is applied with random strength to different matrices

Flux Blend Region

Blend

The effect is stronger near the specified node

Flux Blend Sine Wave

Blend

The effect strength is controlled by a sine wave.

Flux Circle

Transform

Arranges the transforms in a circle

Flux Concatenate

Creation

Adds two arrays of matrices together

Flux Evaluate

Evaluate

Creates clones of geometry transformed according to each matrix in the map channel

Flux Filter by Angle

Filter

Removes matrices that are rotated more or less than a specific angle

Flux Filter by Box

Filter

Removes (or keeps) matrices that are within a specific distance from the bounding box.

Flux Filter Overlapping

Filter

Removes matrices that are at the same position

Flux Filter Range

Filter

Removes a number of matrices starting from the specified matric

Flux Initialize Faces

Initialization

Creates an array of matrices at each face of the base object

Flux Initialize Vertices

Initialization

Creates an array of matrices at each vertex of the base object

Flux Initialize

Initialization

Create an array of identity matrices

Flux Lerp Nodes

Transform

Positions matrices between the matrices of two nodes using linear interpolation (Lerp)

Flux Lerp Spacing

Other

Creates new matrices between each preexisting matrix that has the specified spacing

Flux Line Corners

Creation

Each matrix is duplicated. Every pair of matrices is oriented away from the line segment it creates.

Flux Load Data

Data

Copies the matrices from another map channel

Flux Mesh Loft

Meshing

Creates a mesh by lofting a shape along the path defined by the matrices.

Flux Mesh Strip

Meshing

Creates a mesh strip assuming the first and second half of the matrix positions forms the bottom and top of the mesh strip respectively.

Flux Move

Transform

Moves the matrices towards a target node.

Flux Orient Axis

Transform

Orients an axis towards the specified node.

Flux Orient

Transform

Orients each matric towards a target using a primary and secondary axis of orientation.

Flux Orient to Next

Transform

Orients each matrix towards the next one.

Flux Path

Initialization

Creates matrices evenly spaced along a spline.

Flux Redistribute

Creation

Treats the matrices as a path, and redistributes N matrices evenly or randomly between the other matrices.

Flux Replicate

Creation

Creates N copies of the matrices, each offset by some amount

Flux Reset

Transform

Resets all matrices to the identity matrix

Flux Rotate

Transform

Rotates all matrices

Flux Scale to Target

Transform

Scales all matrices according to the distance from a node

Flux Scale

Transform

Scales all matrices

Flux Scatter

Transform

Places matrices randomly on the surface

Flux Store Data

Data

Copies the matrices to another map channel

Flux Translate

Transform

Moves the matrices 
Extending Flux Yourself
While Flux is very flexible and powerful you may find that nontrivial compound effects require a lot of clicking to switch back and forth between modifiers, not to mention your scene will slow down substantially when there are too many modifiers on your stack. This is where you can look into using MCG to create your own Flux tools that combine effects. The graphs for these tools are designed to be small and easy to understand so that you can reuse and extend them.
Some of the samples even show how Flux can be extended to do unexpected things like creating meshes.
Final Words
A big thank you to the amazing team working on Max Creation Graph and to the support of our user community!