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Resize Slots

Use Resize Slots to adjust the dimensions of slots or tabs in selected objects.

You can use Resize Slots to adjust a jointed design that was intended for a material of a different thickness, or to adjust slots or tabs back to their original size after you rescaled an entire design.

This tool works on two main forms of geometry:

  • Slots, like those found in 3D puzzles or partitions in trays, somewhat similar to a traditional halved joint or dado.
  • Tabs, like a tenon or the fingers in a box joint, usually found in boxes and drawers.

Note

This is a separate tool from Add Tabs, which creates small sections of cuts that the laser is commanded to skip, to prevent objects that you are cutting from immediately falling out of the base material.

Using Resize Slots

Before opening the Resize Slots tool, you'll need to know the existing length of the lines you want to adjust. Use the Measure tool to read the length of an individual slot or tab.

Measure Tab

Select all objects with slots or tabs you'd like to resize, then go to Tools → Resize Slots in Selection to open the Resize Slots dialog window.

Settings

slot and tab resizer settings

  • Old Material Thickness defines the current length of the slots or tabs you want to identify and adjust.
  • New Material Thickness defines the length you want to adjust the slots or tabs to.

  • Tolerance specifies an added amount of padding to Old Material Thickness — slots or tabs that are within the range of Old Material Thickness plus or minus Tolerance will be identified by the resizer.

    This helps if the slots or tabs vary slightly in length, or if there are kerf offsets built into the original design.

  • Select Adjust Slot Depth to adjust the bottom/innermost line of slots. This allows you to keep the outer size of the assembled piece the same.

  • Select Adjust Slot Width to adjust the sides of slots. Typically used when the slots are meant to intersect on the interior of a laser cut piece instead of on the corners, like boxes.py's tray insert.

  • Select Adjust Tab Height to adjust the top/outermost line of tabs. This allows you to keep the interior size of the assembled piece the same, while making it bigger or smaller on the outside.

  • Click Apply to implement a given set of adjustments and continue working in the Resize Slots dialog window.

  • Click OK to implement of a set of changes and immediately exit.
  • Click Cancel to immediately exit and discard changes, if you have not already pressed Apply to implement them. To revert changes you already implemented with Apply, exit the Resize Slots dialog window, then press Ctrl/Cmd+Z to Undo them.

Slot Resizer Demo

Troubleshooting

  • The tool doesn't work on internal slots/cutouts/mortises, as it's tricky for the computer to determine which direction they should grow or shrink.
  • The tool searches Ungrouped objects. Exit the Resize Slots dialog and Ungroup your objects if you see a warning message indicating that there are Grouped objects in your selection. Grouped Objects Warning
  • The tool only works on sharp (not filleted/rounded) corners. Some tools (like boxes.py) default to adding small loops on internal corners and small fillets/rounded corners on external ones. Remove the external fillets using the Radius tool and the internal loops using the Offset tool, set to 0.
  • The tool requires well-formed shapes as an input. If the shape has extra nodes, or if any of the lines are technically curves (even if they're straight), it will interfere with slot/tab detection. The highlighted sections in the image below show examples of problematic shapes. Use Optimize Selected Shapes to try to repair these shapes.

example of bad input for slot/tab resizer

For more help using LightBurn, please visit our forum to talk with LightBurn staff and users, or email support.