> For the complete documentation index, see [llms.txt](https://help.clabassistant.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://help.clabassistant.com/manage-a-project/preview-comparison.md).

# Compare Pattern Previews

**Preview comparison** overlays a reference on the current pattern so you can inspect changes or compare designs. Use a capture of the current preview, another saved project, or an imported DXF. The options shown depend on what is available in your workspace.

To compare measurement values between two projects from the Dashboard, see [Compare Projects](/manage-a-project/compare-projects.md).

## Capture the current preview

1. Arrange the pieces you want to compare.
2. Click **Pin preview for comparison** in the preview toolbar.
3. Change your measurements or geometry and compare the result with the captured reference.
4. Open **Preview comparison** to adjust opacity or hide and show the overlay.

When **Current preview** is offered, use it to replace the reference with a new capture.

## Compare with another project

1. Open **Preview comparison** and choose **Another project**.
2. Search by project name or code, entering at least two characters.
3. Select an active, configured project in the current workspace. The project already open in the editor is excluded.
4. Click **Use as reference**, or double-click the project card, to load its saved configuration as an overlay at real scale.
5. Review the pieces and use the comparison controls to select, hide, or move reference pieces.

Loading a reference does not change either project's measurements or configuration. The overlay is a snapshot of the saved configuration at the time you load it; later changes to the source project do not update it automatically. Choose **Another project** again to load a fresh reference.

This **Use as reference** button adds a temporary comparison only. To create a new project from an existing design, see [Start from a Reference Project](/manage-a-project/reference-projects.md).

## Import a DXF reference

1. Open **Preview comparison** and select **Import DXF**.
2. Choose an ASCII `.dxf` file, up to 2 MB.
3. Review the detected units and piece dimensions. If units cannot be detected, choose the correct unit before continuing.
4. Select the pieces to import. If needed, use **Rotate all 90°** to turn every piece counterclockwise; this also rotates unselected pieces.
5. Confirm the import and inspect the overlay at the displayed physical scale.

Binary DXF files must first be exported as ASCII DXF from your CAD software. If some contours cannot be read, Clab shows a notice; check the imported pieces before comparing them.

The DXF is a visual reference. Importing it does not convert its pieces into editable Clab pattern pieces.

## Adjust the comparison

Use the comparison popup to:

* For a project or DXF reference, select which pieces are visible and enable **Show internal lines** when offered. Internal lines are initially hidden.
* Change the overlay opacity or use **Hide comparison** / **Show comparison**.
* Choose **Move reference pieces** to align the overlay with your live pattern. Drag a piece near a visible point to snap; hold **S** to suppress snapping. Arrow keys move a focused reference piece by 1 mm, or 10 mm with **Shift**.
* Choose **Another project** to load a different saved project, **Change DXF** to replace the file, or **Current preview** to capture the current pattern when available.

Press **Escape** to exit reference movement. Hold **Space** and drag to pan. **Zoom all** fits the live pattern and visible reference pieces together.

## Clear or keep a comparison

Only one reference is active at a time. Loading another project, importing a DXF, or capturing a new preview replaces it; canceling the selection or import preserves the existing reference.

**Clear** removes the overlay. References and their positions are temporary and are discarded when you reload or leave the editor. Save a [Pattern Version](/manage-a-project/pattern-versions.md) when you need to retain a project state for later work.