Modifier Tools¶
The modifier tools, as the name suggests, are primarily used to modify existing shapes.
The tools are:
Offset¶
Hotkey = Alt + O
The offset tool is used to create outlines around existing shapes, either inward or outward, offset from the original by a given amount. We use the offset tool in the 'Making a Simple Project' topic, so that's a great introduction.
The corner style option chooses how outward corners are offset:
The offset tool remembers the last set of options you used, and if you hold the Ctrl key when you click the offset button, it will perform the offset operation using the previous settings, without bringing up the dialog.
Weld¶
Hotkey = Ctrl/⌘ + W
Clicking on the Weld icon will join all the selected shapes into a single entity that is the outline of all the selected shapes. Note that Weld requires closed shapes, but will accept an arbitrary collection of inputs, and tries to do the right thing, but sometimes gets it wrong. If you weld something and the middle content disappears, use Boolean Union instead.
Boolean Union¶
Union is similar to weld, but works with 2 selected objects only. However these selected objects can actually be grouped items, not just a single vector shape.
Boolean Subtract¶
Hotkey = Alt + -
Boolean subtract (also called Boolean Difference) will remove the area that the second selected shape overlaps the first shape by. The order in which you select shapes will determine the outcome. This tool also works with grouped items. If you end up subtracting the items in the wrong order, Undo, then perform the operation again - The undo switches the order of the items, so a simple Undo and click-again of of the Subtract button is a quick fix.
Boolean Intersection¶
Hotkey = Alt + *
This will create a shape from 2 selected shapes that has an outline defined by only the areas in which the shapes overlap. This tool also works with grouped items.
The three different Boolean operations are shown here:
- Union keeps the area covered by either shape - it merges them.
- Difference is the 2nd shape removed from the first.
- Intersection keeps the area covered by both shapes.
Boolean Assistant¶
Hotkey = Ctrl/⌘ + B
Because it can be hard to remember which operation (or which order) is going to do the thing you want, we've added a new Boolean Helper that will let you preview each of the Boolean operations before deciding on one.
Click any of the first 4 buttons to see what that operation will look like, or click the 'Reset' button to see the original shapes. If your design is not complex, hovering over the buttons will also work. When you see the result you want, click the 'Ok' button to keep it, or click 'Cancel' to revert.
Video Walkthrough of the Boolean Operations¶
Click for a Boolean demonstration video
The above video describes in more detail how the various Boolean operations differ, and why welding text to a circle should be done with a Boolean Union instead.
Grid Array¶
The Grid Array tool allows you to copy a shape (or shapes) with regular spacing horizontally, vertically, or both, and includes options to adjust spacing, to shift odd rows, mirror the shapes, and more.
The X and Y columns settings let you specify how many copies of your shape to make in each direction.
Total Width and Total Height are convenience options that allow you to tell it the maximum size to occupy/ It will set the X Columns and Y Rows values to whatever is necessary to fill the specified size without going over, based on the other provided settings.
Spacing can be specified between edges (how much padding between shapes) or between centers (absolute object spacing).
Column and Row Shift values let you offset alternate columns or rows, and you can mirror them as well, allowing you to more efficiently pack oddly shaped items together, like this:
Virtual Arrays¶
There is also a Virtual Array option that can be selected by checking "Create Virtual Array" at the bottom of the Grid Array dialog. Instead of making copies of the original shapes, this will generate virtual clones of the original that stay synced at all times. When using a virtual array, the virtual clones will render with a dashed outline and muted fill color to denote they are virtual:
Note that these virtual shapes are not selectable and will always be laid out based on the array options you provided. However, any changes made to the original shapes are automatically reflected in the array.
Beyond just altering the original shapes, there are many operations that can be done after the fact to virtual arrays, all of which are available from the shape context menu. This menu is available from any shape that is currently part of a virtual array. You do not have to select all shapes in that array first.
- Edit Array: Display the "Create Grid Array" dialog again, but for this existing array. This allows you to modify any of the parameters and even convert it back into a normal array, by unchecking "Create Virtual Array".
- Duplicate Array: Virtual arrays cannot be selected directly, only the shapes included in them. So this allows you to duplicate an entire virtual array and all of the shapes in it.
- Flatten Array: Convert the virtual array into a standard array where all shapes are separate copies and no longer synced to the original shapes.
- Remove from Array: Remove the currently selected shape(s) from the virtual array.
- Add to Array: Add any currently selected shapes not in the virtual array to the array. Note, you must select at least one shape that is in a virtual array and one shape that is not in a virtual array currently.
Circular Array Tool¶
The Radial Array (or circular array) tool lets you create copies of a shape (or shapes) around a central point. This is useful for creating ornamental patterns, clock faces, and more.
You can manually enter the point of rotation, but it's much simpler to create a shape to use as the center point, and select that shape last. The created copies can be rotated or not - Numbers on a clock, for example, are often left upright for readability, but roman numerals are usually rotated.
In the above example, the small center circle was selected last, and the 'Use last selected object position as center' option is chosen, along with 'Rotate object copies' to produce the pattern.
Start Point Editor¶
The Start Point edit tool lets you tell LightBurn where to start cutting a shape, and in which direction. By default, the starting point is the first point of the shape, and the direction will be the direction that the selection marquee animates in. In the Optimization Settings, if you tell LightBurn to choose the best starting point or best direction, it can choose a different point than the default if it will reduce cutting time. The Start Point editor lets you force the starting point and direction.
With a shape selected, click the 'Start Point' tool and you'll see the starting point and direction indicated by an arrow. If the arrow is gray, it means this shape is displaying the default point and direction, but it is not forced. If you click any node on the shape, the arrow will move there, and turn blue, indicating that the user has chosen this as the starting point and direction.
Holding Shift and clicking a point will choose the opposite direction, and holding Ctrl and clicking the shape will clear the starting point back to the default.
Radius Tool¶
You can fillet (round over) sharp corners using the Radius Tool. It also allows you to remove radiuses from corners, turning them into sharp points.
Fillets have all kinds of applications, and they can be combined to form more complex shapes.
Add a Radius¶
To add a radius, click the radius tool, change the radius value to reflect the size you want your rounded corner to be. Then click on the object, and the specific corner you want to round out.
If you change the radius to a negative number it takes a fancy little bite out of the corner. 
Remove or Change a Radius¶
As of release 1.3, you can use the radius tool to delete rounded corners (returning them to a sharp one) by clicking on them. This even works on imported designs that were made in different software, as long as the software exported actual arcs.
After removing a radius you can then apply a differently-sized one to the corner, as normal.
Troubleshooting Radiuses¶
Radiuses can only be applied where straight (vector) lines meet in a connected corner, and where there is room for the radius to be applied.
When the radius tool is active, the icon changes as you hover over a corner to indicate whether or not the radius tool can be used.
| Icon | Meaning |
|---|---|
 | Click to fillet corner |
 | Click to remove fillet |
 | Can't fillet - corner is next to a curve |
 | Can't fillet - not enough space |
If the cursor isn't appearing as you hover over a corner, make sure you've selected the radius tool in the Creation Tools. The Radius icon should be highlighted. Also check that you have selected the object you wish to edit by clicking on it.
If that still isn't working, check that the connected lines are straight. It's possible for lines that appear straight to be curves, especially in imported files. Select the Edit Nodes Tool, hover over the line either side of your corner and hit L on your keyboard.
If a radius still can't be applied it might be because the two lines that make up the corner aren't actually joined at that point. To check, move the corner using the Edit Nodes Tool, if it splits off into two lines, bring the one you moved back toward the other so that they snap together and join, and then try the radius again.
If you are having trouble converting a rounded corner back into a sharp one, it could be because there is not a true arc at the corner. This is most common with imported shapes, because some programs export arcs as a series of tiny lines. You can try repairing these with Optimize Selected Shapes.
To exit the radius tool, hit Escape on your keyboard.