> For the complete documentation index, see [llms.txt](https://stage-precision.gitbook.io/grid/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://stage-precision.gitbook.io/grid/timeline/layer-types/parameter-keyframe-layer.md).
# Parameter / Keyframe Layer
Record object parameter changes into Timeline Keyframes, manually add and edit Parameter Keys, and manage which objects and Parameter Layer are active for recording.
The **Parameter Layer** is primarily designed for **object-based parameter recording**.
Objects can be registered for recording, and while the Timeline is recording, parameter changes on those objects are automatically written as Keyframes.
The Parameter Layer can also be used to manually create individual Parameter Keyframes, although advanced value animation with Bezier curves and a dedicated Curve Editor is better handled by the **Curve Layer**.
***
## Parameter Layer vs Curve Layer
The Parameter Layer supports Parameter Keyframes and interpolation, but its primary purpose is **recording object Parameter changes**.
For deliberately authored value animations that require detailed curve shaping, Bezier interpolation, and a dedicated Curve Editor, use the **Curve Layer** instead.
{% content-ref url="/pages/hY7HuqEfebPpKO0Q64SR" %}
[Curve Layer](/grid/timeline/layer-types/curve-layer.md)
{% endcontent-ref %}
***
## Recording Target Layer
A Timeline can contain multiple Parameter Layers, and multiple Parameter Layers can play back their existing Keyframes at the same time.
The red **R** does not enable or disable playback of a Parameter Layer.
Instead, it defines which Parameter Layer is currently used as the destination for:
* new object recordings
* manually created Parameter Keyframes
Only one Parameter Layer can be selected as the **recording target** at a time.
Existing Keyframes are still evaluated and applied during playback regardless of whether the Layer currently has the red **R** indicator.
***
## Registering Objects for Recording
Objects can be registered individually for Timeline recording.
In the header of an object's Inspector, enable the round **Recording** control.
When enabled, the indicator turns red.
Any number of objects can be registered for recording at the same time.
If a Parameter Layer is currently active, registered objects immediately appear underneath that Layer as object entries.
No Keyframes need to exist yet. This intentionally provides a visible list of all objects that are prepared for the next recording.
### Disabling Recording from the Parameter Layer
Each registered object shown in the Parameter Layer has its own Recording indicator.
Click the red indicator to deactivate recording for that object directly from the Timeline.
If the object is no longer registered for recording and no recorded Parameter data remains, its entry automatically disappears from the Parameter Layer.
***
## Recording Parameters
When Timeline recording is started, changes to parameters of all registered objects are written into the active Parameter Layer as Keyframes.
Each recording pass creates its own Timeline Item containing the recorded Parameter data.
These recording Items can subsequently be moved, resized, or duplicated like other Timeline Layer Items.
{% hint style="info" %}
The Parameter Layer is the main Timeline Layer used for object-based recording.
For detailed information about the complete recording workflow — including **Recording Takes**, managing and replaying recordings, and exporting recorded data to **Unreal Engine**, **FBX**, or **CSV** — see the dedicated **Recording** documentation.
{% endhint %}
***
## Viewing Recorded Parameters
By default, the Parameter Layer only shows the names of the recorded or registered objects.
Double-click an object name to expand it.
The expanded view shows the individual Parameters and their Keyframes.
This keeps the Layer compact when working with many recorded objects while still allowing detailed Keyframe editing when required.
***
## Manual Parameter Keyframes
Parameter Keyframes can also be created manually without recording.
Right-click a Parameter and select:
**Add Key**
Grid Studio creates a Keyframe using the Parameter's current value at the current Playhead position.
### Main Timeline
Grid Studio projects can contain multiple Timelines, so **Add Key** needs to know which Timeline should receive the new Keyframe.
Configure the destination Timeline under:
**File → Project Settings → Processes → Main Timeline**
The selected Main Timeline is used when creating Parameter Keys directly from Parameters.
The active **R** Parameter Layer inside that Timeline is used as the destination Layer.
### Adding a Key Outside an Existing Item
If **Add Key** is used at a Playhead position outside an existing Parameter Item, Grid Studio displays the **Key Parameter Options** dialog.
Available options are:
* **Append previous**
* **Prepend next**
* **Create new block**
This allows you to decide how the new Keyframe should be associated with the surrounding Parameter Items.
***
## Keyframe Playback
Parameter values are evaluated while the Playhead is inside the corresponding Parameter Item.
Between Keyframes, values are interpolated **linearly** by default.
When the Playhead is moved or jumps to another position inside the Item, the Parameter is immediately set to the value represented by that Timeline position.
If the position lies between two Keyframes, the corresponding interpolated value is applied.
Outside the Parameter Item, the Timeline is effectively **inactive for that Parameter** and does not control its value.
***
## Editing Keyframes
To edit an individual Keyframe, first select it by dragging a small **selection rectangle** around it in the Timeline.
Once the Keyframe is selected, its properties are shown in the **Inspector**.
The Inspector allows its:
* **Time**
* **Value**
to be changed precisely.
Keyframes can also be moved directly along the Timeline using drag and drop.
#### Duplicating Keyframes
Select a Keyframe and press:
**CTRL**** + ****D**
The duplicated Keyframe is created at the **same Timeline position** as the original.
You can then click and drag the duplicated Keyframe to move it to a new position on the Timeline.
### Deleting Keyframes
Select a Keyframe and press:
**DEL**
### Delete All Keys
Double-click the object entry to expand its Parameters.
Use the right-click menu and select:
**Delete All Keys**
to remove all Keyframes belonging to that object.
If the object is also no longer registered for recording, its entry automatically disappears from the Parameter Layer.
