> 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/camera-calibration/before-you-start.md).

# Before You Start

Before starting a camera calibration in Grid Studio, make sure you understand what kind of camera setup you are working with, which reference data is available, and which parts of the system need to be calibrated, updated, or reused.

Not every setup requires a full calibration. In many cases, existing calibration data can be reused and only the changed part of the setup needs to be updated.

This page helps you prepare the calibration workflow by answering five questions:

1. What type of camera movement setup are you using?
2. Which calibration reference will be used?
3. Which calibration data already exists?
4. What has changed in the physical setup?
5. Which tool or workflow should be used?

## Understand the Project Coordinate System

All camera calibration workflows are solved relative to the Grid Studio project coordinate system.

The project origin, object positions, Calibration Screens, Measurement Points, folders, imported geometry, and camera objects all exist inside this shared 3D space.

The calibration does not create a new world origin by itself. Instead, it solves the camera, tracking, screens, or movement data relative to the reference objects that already exist in the Grid Studio project.

#### Calibration References Define the Spatial Relationship

Calibration Screens and Measurement Points act as known references inside the Grid Studio world.

This means the calibration result depends on where these references are placed in the project.

For screen-based workflows, the camera is calibrated relative to the Calibration Screens.

For Manual Marker workflows, the camera is calibrated relative to the Measurement Points.

If the Calibration Screens or Measurement Points are moved, rotated, or aligned differently in the project, this is usually easy to update.

In many cases, you do not need to capture new data. Simply run the calibration again and Grid Studio will recalculate the result relative to the updated reference placement.

#### Master Screen or Master Panel

For screen-based workflows, one screen, panel, or column is usually used as the fixed spatial reference.

This reference is placed in the Grid Studio world first.

Grid Studio can then calculate and place the other screens, panels, or columns relative to this fixed reference during calibration.

This is especially important for Multi Screen setups, where one panel or column can define the anchor position while the remaining connected panels are solved relative to it.

{% hint style="info" %}
The fixed reference does not replace the Grid Studio world origin. It defines where the calibrated screen setup sits inside the Grid Studio world.
{% endhint %}

#### Re-Aligning References Later

Calibration references can be adjusted later if the project coordinate system or reference placement needs to change.

For example, you can:

* move a Calibration Screen
* move a Multi Screen master panel or column
* adjust a Folder that contains Measurement Points
* realign measured points to a different project origin
* update the placement of imported reference geometry

After changing the reference placement, the calibration can be solved again relative to the updated references.

In many cases, this can be done without capturing new image data, as long as the existing captures, tracking data, and detected reference points still describe the same physical setup.

{% hint style="info" %}
This makes it possible to realign the project coordinate system or reference objects and then recalculate the calibration result without repeating the full capture process.
{% endhint %}

## 1. Identify the Camera Movement Setup

The first step is to understand how the real camera moves and how this movement is represented in Grid Studio.

### Fully Tracked Camera

A fully tracked camera system provides position and rotation data, usually from an optical tracking system, mechanical tracking system, or another 6DOF tracking source.

This setup usually requires a tracking calibration or tracking alignment, because the tracking data does not automatically describe the exact optical center and viewing direction of the real camera.

### Rotation Only / Pan-Tilt Camera

A rotation-only or pan/tilt camera does not move freely through 3D space. Instead, it rotates around one or more axes.

This type of setup uses a dedicated calibration workflow, because Grid Studio needs to understand how the rotation data relates to the real camera view.

### Camera Rail or Axis System

A camera rail, pole, or axis system moves the camera along a defined mechanical path or axis.

This setup may require additional movement data and a dedicated axis object in the project. The calibration needs to define how the mechanical movement relates to the virtual camera movement inside Grid Studio.

### Static Camera

A static camera does not receive live tracking or movement data.

Depending on the use case, it may still require lens calibration, screen calibration, manual alignment, or a fixed camera transform inside the virtual scene.

### Multiple Data Sources

Some setups use more than one data source for a single camera. For example, one system may provide camera position and rotation while another system provides lens encoder values such as zoom and focus.

In this case, the camera setup needs to combine multiple inputs before it can be used for calibration. This is an advanced setup and is explained in a separate section.

***

## 2. Choose the Calibration Reference

Grid Studio needs known visual or spatial references to solve a calibration. These references tell Grid Studio where known points or surfaces are located in the real world.

There are two main types of calibration references:

* generated marker images on known physical reference surfaces
* Manual Markers using measured 3D points

{% content-ref url="/pages/jwoIZHRaJKEznyLL2tXS" %}
[Choosing the Right Calibration Tool](/grid/camera-calibration/before-you-start/choosing-the-right-calibration-tool.md)
{% endcontent-ref %}

### Generated Marker Screens and Surfaces

The standard marker workflow uses calibration images generated by Grid Studio. These marker images are displayed or placed on known physical reference surfaces.

These surfaces can be:

* LED walls
* monitors
* TVs
* printed boards
* other precisely measured calibration targets

The important requirement is that the physical size of the marker surface is known.

For digital screens, the marker image must be displayed pixel-correctly. For printed boards, the physical print size must match the dimensions configured in Grid Studio.

Projection-based marker workflows are not part of the standard generated marker workflow, because the final projected marker size can be difficult to guarantee accurately unless it is measured and controlled separately.

{% content-ref url="/pages/cAxk1UkOnjgooTgZBVig" %}
[Calibration Screens](/grid/camera-calibration/before-you-start/calibration-references/calibration-screens.md)
{% endcontent-ref %}

### Manual Markers / Measurement Points

Manual Markers are used when **Calibration Screens** or **Calibration Images** cannot be used in the real environment.

In the calibration tools, this workflow is referred to as **Manual Markers**. The actual 3D point objects created in the Project Tree are called **Measurement Points**.

Each Measurement Point represents a measured 3D position in the physical environment. During calibration, these points are manually referenced in captured camera images.

Examples include:

* field corners
* field lines
* penalty box corners
* goal lines
* center lines
* architectural points
* stage measurement points
* measured floor markings
* other clearly identifiable real-world positions

Manual Markers are useful for environments such as stadiums, arenas, venues, stages, or architectural spaces where it may not be practical to place LED walls, monitors, or printed calibration boards in the scene.

This workflow usually requires an already calibrated lens. A common workflow is to first create a Lens Profile with a Calibration Screen workflow and then use Manual Markers on location to align the tracking system to the measured environment.

{% content-ref url="/pages/0bGDLXp2eYRsl8OdTAnf" %}
[Manual Markers / Measurement Points](/grid/camera-calibration/before-you-start/calibration-references/manual-markers-measurement-points.md)
{% endcontent-ref %}

***

## 3. Understand What the Tools Can Create or Update

Different tools create or update different types of calibration data.

{% content-ref url="/pages/jwoIZHRaJKEznyLL2tXS" %}
[Choosing the Right Calibration Tool](/grid/camera-calibration/before-you-start/choosing-the-right-calibration-tool.md)
{% endcontent-ref %}

### Lens Profile

A Lens Profile describes the optical behavior of a lens.

It can include lens distortion, focal length behavior, center shift, nodal shift, or other lens-related parameters depending on the workflow.

Lens Profiles are stored as objects in the Project Tree. They are usually created by a calibration workflow, or updated when an existing Lens Profile is linked as an output target. They can often be reused as long as the same lens and lens settings are used.

### Alignment Profile

An Alignment Profile describes how the camera, tracking data, lens, and reference setup relate to the virtual scene.

Alignment Profiles are stored as objects in the Project Tree. They are usually created or updated by a calibration workflow and are used to align camera tracking, Measurement Points, Calibration Screens, or other reference data.

### Screen Placement and Shape

Screen objects are usually created and configured before calibration. Their size and basic setup are defined by the user.

Some calibration and repositioning tools can calculate the placement, orientation, and shape of these screens in 3D space. This result is then applied to the existing screen objects, usually by using an Apply button in the tool.

The tool does not create the screen object itself. It updates or applies the calculated screen placement and geometry to the existing screen setup.

### Axis Calibration Data

Axis or rail-based workflows can create or update calibration data for an **Axis 2D** object.

This data describes how the real mechanical movement of the camera system behaves in 3D space.

An Axis 2D setup usually receives two movement values, such as:

* rail / position
* pole / lift

During calibration, Grid Studio learns how these two values relate to the actual 3D camera movement. This can include real-world mechanical behavior such as curved rails, slight twisting, bending, pole or lift tilt, or other small alignment errors.

After calibration, this learned movement data is stored in the Axis 2D object and used to drive the child Camera Object correctly.

### Object or Parent Transform

Some repositioning tools do not create profiles.

Instead, they reposition an existing camera or camera system in the 3D scene by applying offset values to a parent folder or parent object. This keeps the existing Lens Profile and Alignment Profile unchanged while moving the complete calibrated system in space.

***

## 4. Check Existing Calibration Data

Before choosing a workflow, check which calibration data already exists and whether it is still valid.

Ask the following questions:

* Do you already have a valid Lens Profile for this lens and lens setting?
* Has the lens changed?
* Has the camera body changed?
* Has the tracker mount or tracking system changed?
* Has the LED wall, monitor, printed board, or reference surface moved?
* Has the stage coordinate system changed?
* Are the same screens or reference surfaces still valid?
* Are you adding a second camera to an already calibrated stage?
* Are you using a pan/tilt camera, camera rail, axis, or another special movement setup?
* Are multiple data sources needed for one camera?

The correct workflow depends on what changed in the physical setup and which calibration data can still be reused.

***

## 5. Choose the Correct Tool or Workflow

The tool selection depends on the physical setup, the available input data, and the calibration data that should be created, updated, or reused.

For example:

* Use a full calibration workflow when setting up a new fully tracked camera system with lens, tracking, and calibration screens.
* Use a rotation-only workflow for pan/tilt or rotation-only camera systems.
* Use a lens-only workflow when only the lens needs to be calibrated.
* Use a tracking alignment workflow when the lens and screens are still valid, but the tracker offset or tracking system has changed.
* Use Manual Marker workflows when generated marker screens cannot be used and measured 3D points are available.
* Use repositioning workflows when an existing calibrated camera system should be moved or aligned without changing the underlying profiles.
* Use screen alignment or screen repositioning workflows when existing screen objects need to be positioned or updated.

The detailed tool selection table is explained in the next section: **Choosing the Right Calibration Tool**.

{% content-ref url="/pages/jwoIZHRaJKEznyLL2tXS" %}
[Choosing the Right Calibration Tool](/grid/camera-calibration/before-you-start/choosing-the-right-calibration-tool.md)
{% endcontent-ref %}

***

## 6. Before You Continue Checklist

Before continuing with the setup guide, make sure the following points are clear:

* You know what type of camera movement setup you are using.
* You know whether you will use generated marker images or Manual Markers.
* The real-world dimensions of your screens, boards, or reference surfaces are known.
* For digital screens, the marker image can be displayed pixel-correctly.
* For printed boards, the physical print size matches the configured dimensions.
* For Manual Markers, the 3D positions of the reference points are measured.
* The camera image can be received by Grid Studio.
* Any required tracking, movement, encoder, or axis data is available in the project.
* Existing Lens Profiles, Alignment Profiles, screen setups, or axis calibrations have been checked.
* You know which part of the setup has changed and which part can be reused.
* You know whether the selected tool should create a new profile, update screen placement, update axis data, or reposition an existing object or parent folder.

Once these requirements are clear, continue with the tool selection and project setup sections.