Linking and Sharing

Connecting Parameters

As described in the Generators and Modifiers section, all parameters of any kind, always have two slots:

Autograph gives you the ability to connect parameters together without using any expressions, representing this connection on the first slot.
We distinguish two methods:

Linking

Let's focus on the Generator slot:

In the following example, the layer Source is connected to a Reader, while its Mask is not connected to anything.

A link is a one-way relationship between two parameters:

Right-click on a parameter to display the options for creating a link:

In the example below, two layers are selected to display their respective trees in the Selection Overview. This allows you to quickly switch transformation parameters from one layer to another, without changing the selection in the Timeline.

Once this link between these two Scale parameters has been established:

Driver and Driven at the same time

A parameter can be both controlled by another parameter as well as act as a Driver, taking control of a third parameter.

So we have a multi-level dependency:

Param_01 -> Param_02 -> Param_03: Param_01 is the Driver for Param_02, which is itself the Driver for Param_03.

The color surrounding the slot and the icons allow you to see these two states at a glance:

Right-click on a Driven parameter to remove the link with the Driver:

The parameter value prior to creating the Link is shown again and can be manipulated, having been stored.

Inspecting Linking Dependencies

While visual clues make it easy to see which parameters are Drivers/Driven, it's not clear which ones specifically control which.
Right-click on a parameter to find out about these dependencies.

This option is only available on Driven parameters, which can only be connected to a single Driver.
It allows you to directly select the Driver, which also:

Show Linked Parameters:

This option is only available on the Driver, which can be connected to several Driven parameters. By selecting this function, a list of connected Driven parameters is displayed in a floating window.
Hover the mouse over each line:

Follow Time Option

When two parameters are linked, the Driven one is a copy of the Driver and reflects any modifications applied to it.
If the left logo's Scale (the Driver) is animated with two keyframes:

But there is an option that allows you to take into account Time Offset differences between Driver and Driven parameters.
To enable it, right-click on a Driven Parameter and select the Follow Time option.

Once this option has been enabled, the logo representing the yellow plug is outlined in blue with a blue stopwatch, quickly making it obvious that this option is active.

Sharing

Difference between Linking and Sharing

The Link section describes how to connect one parameter to another, which can be done if they are the same type and dimension. With linking you have the concept of the driver and driven parameters, since one parameter controls the other and prevents it from being modified. The driver value or state overrides the driven one.
In order to dive deeper into the interaction between parameters, Autograph also offers the concept of sharing instead of linking, where parameters are both drivers and driven:

Note that in the case of linking, the connection goes in only one direction. In the case of sharing, it goes in both directions.
In the video below, the Scale values, initially independent as seen at the beginning, are then shared between the two layers.

To show that a parameter is shared with one or more other parameters, its Generator slot (the icon representing a plug and socket) will light up and be outlined in purple.

Tip:When several parameters are shared, they are said to belong to the same Share Group. We'll see just below how to remove parameters from a Share Group using the Unshare function.

In a nutshell

Note:

Remember, the only constraint is that in order to share parameters they must be the same type and the same dimension. You can't share Source Text with Position. It would not make sense. You can’t share a Position parameter that has 2 dimensions with a Rotation that has only one dimension. However, through Separated mode, you can split a 2D parameter into two 1D parameters. Then you can link either the X or Y Position value to the Rotation.

For more detail on splitting dimensions, please refer to the Managing dimensions section.

Unsharing Parameters

To remove a parameter from a Share Group and make it independent again, right-click on a Shared parameter and select Unshare.

Automatically Shared Parameters:

Unsharing a parameter is a frequent action in Autograph, and not just for parameters that have been manually shared.

During certain actions, parameters are automatically Shared, like when you drag an image from the Project Panel into the Timeline to create a new layer in a composition. Inspecting this layer, we see the Reader parameters it uses as a Source and all but one of the parameters are Shared.

This behavior is very useful when the image/reader is used by several Layers. You can select the Reader in the Project Panel and modify one of its parameters, such as Mirror H, to flip a logo horizontally. As all layers using this Source have their parameters shared with those of the Reader, all logos will undergo this horizontal flip.

In the case of the Reader, the Output Parts parameter is Unshared by default, as its purpose is to select a layer in a PSD file or a pass in an OpenEXR file. This makes it possible to drag the same Reader into a composition several times and then quickly select a layer or pass without having to unshare the parameter manually.

Tip:When creating a composition from a PSD file, each layer uses the same Reader, but changes its Output Parts parameter, which is unshared by default.

Creating a Local Variant by Unsharing:

Duplicating a layer will also produce two layers sharing the same Reader as sources, with all parameters shared between the three elements.

But it's now possible to Unshare this parameter locally for a single layer and thus create a local variation.
Here's an example after duplicating the same layer 3 times to create smaller versions on the right of the screen:

We've created a local override of the Mirror H parameter for this layer's source.
This method can be applied to any parameter. Imagine several logos sharing the same animation for the Rotation and Scale parameters, but with a different Position. This avoids copying hundreds of keyframes. By animating shared parameters once, they will all be animated at the same time.

Tip:To achieve this type of local modification in After Effects, you have to import footage several times into the Project Panel and go through the Interpret Footage panel to modify, for example, the FPS for one of these instances. Autograph's sharing/unsharing concept makes it possible to create as many local variations as possible with a single Reader.

Inspecting Sharing Dependencies

Just like with links, simply right-click on a shared parameter and select Show Shared Parameters to see a list of all parameters in the same Share Group.
The video below shows the example of three logos, one of which is no longer shared with the Mirror H parameter.

Starting from a parameter belonging to Comets_Big, we can see that the parameter Comets_Small_02.Mirror.H is not on the list.
As with links, moving the mouse over the list displays a preview of the parameter.

Everything can be shared

Sharing is not limited to just two parameters, it is possible to share this value with hundreds of parameters across compositions, 3D scenes - you name it! We've gone over sharing a numerical value between several parameters, but you can share absolutely anything in Autograph.
Here are some examples of what you can share:

In this last case, you may wonder why you would want to make a complete copy of a layer that would overlap perfectly with its identical copy, no matter what changes are made.

So you can synchronize thousands of parameters, used by hundreds of layers to locally take control of one of them.