lc-qcad

This repository contains two plugins for QCAD. They are designed to prepare drawings for laser cutting.

Primarily they should be used for model making.

Dependencies

Nothing but QCAD >= 3.20.

Install

Download the whole project with the download-button in the upper right or by cloning it using Git.

Take the two zip files in the dist directory and unpack it into scripts/Misc/Modify of your QCAD installation. If neither Misc nor Modify exists, create them!

Attention

Always use a copy of your original drawing!

Conditions

There are a few things that you should consider before using the plugins.

• parts may not overlap
• contours (inner and outer) and engravings must be clearly separated from each other
• contours have to be closed
• all layers must be visible and unlocked
• avoid nesting parts

Prepare Plugin

The main purpose of the first plugin is to prepare the drawing for laser cutting. The result is a drawing with only two layers: one for the cuttings/contours and one for the engravings.

Here are the features:

• all entities will be moved to layer 0 (except engravings)
• allowed entities are lines, polylines, arcs and ellipses
• not wanted entities like hatches, dimensions, texts and all kind of constructive entities (points, infinite lines, rays) will be removed
• contours and engravings of one part don't need to be grouped in a block
• styles will be unified
• blocks will be resolved
• removes very small lines
• removes duplicates
• merges entities into polylines
• polylines/polygons will be simplified
• offsets contours by a given value

Prepare your drawing as explained in the section before and open the plugin via Misc > Modify > Prepare.

Set the values in the dialog and confirm it.

Adjustable settings are:

• Layer Engraving
  • name of the layer with engravings
  • all engravings must be on the area between inner and outer contours
  • small overlapping is allowed, as long as all points are on the area between the contours
• Offset
  • all cuttings will be adjusted by that offset (the areas of inner contours becomes smaller, outer contours bigger)
  • practically it is the half of the cutting width
  • be very careful with this setting

AddGaps Plugin

The second plugin can be used to add gaps to the cuttings. Call this plugin via Misc > Modify > AddGaps.

You have to select the cutting layer first. Hover to one of the lines and you will see a preview of the new gap positions. If the preview is okay, just click to lock it. You can unlock a preview with a second click. Add gaps to other segments and finally terminate the plugin with a right click in the document.

Currently the plugin can only work with lines, arcs, circles and polylines.

The plugin has two settings:

• Width
  • it's the width of the gap
  • if the edge length is less than 1.5*width, the whole segment will be deleted (it works only for line segments)
• Distance
  • distance between two or more gaps
  • if an edge length is smaller than 1.75*distance, then only one gap will be added in the middle
  • it's just a guiding value

License

Published under the MIT license.

Copyright

2018-2023, Ronald Römer