Laser cutting with Onshape

Onshape is CAD software that runs entirely in your browser. So you don't have to install anything. It is aimed at technical drawing and engineering and is comparable in functionality to SolidWorks and Fusion360. There are paid subscriptions, but if you don't mind your models being publicly accessible, you can use all the features for free.

Laser cutting from onshape can be done in a number of ways. In this example we are going to have a wooden cabinet laser cut.

You can view the 3D model with this link.

The link to the model in Onshape is read-only. If you create an Onshape account you can clone and adjust the model. For example, you can adjust the variable (plate thickness). You will see that all connections scale nicely. You can best learn how to draw in Onshape in their learning center.
Below you can read how you can export for laser cutting:

Method 1: Part by part.

This method is fastest if you only have a few parts, or if you want to post-process the 2D drawings.

1. Go to the 'Part Studio 1' tab
2. Right click on the top shelf and click 'Export as DXF\DWG..'
3. Give the part a name (optional), choose 'DXF', 'Release 14', 'Download', and click Export.
4. Follow these steps for all parts you want to laser cut.

The dxfs can be used directly by Snijlab. Drag them into the uploader & choose the right material to order.

Method 2: Drawings.

This is a bit more work initially, but produces nested drawings that are potentially cheaper to cut. Moreover, the nests are dynamic: if you change something in your model, all nest drawings will update accordingly.

1. Search for 'Snijlab drawing template' in the public documents. Open the document and click 'Make a copy'. The template is now in your own library.
2. Open the document you want to laser cut, click on the plus sign at the bottom left and choose 'Create Drawing..'
3. Now you can choose a template. Filter by 'Created by me'. The template from step 1.
will now appear
4. Choose 'Snijlab drawing template.dwt' template and click 'Ok'. The new Drawing now opens.
5. Click 'Insert View', choose a part and add it to the Drawing. Make sure you choose the correct view (top or side). Add more parts until the drawing is full.
6. If you have more parts than fit on one plate, repeat steps 2-4 to create another Drawing. (note: do not create additional Sheets in one Drawing, but create multiple Drawings)
7. Click on menu and 'Print..' to export the drawing to a vector PDF.

The PDFs are directly suitable for Snijlab. Drag them into the uploader and choose the correct material to order.

If you now make an adjustment to your model you will see that a yellow update button appears in your Drawings.
Click on that to allow the changes to your model in your Drawing.

Conclusion:

CAD design makes it possible to get complex projects right the first time. Drawing in 3D takes some time, but you can almost always recover that time by encountering problems at an early stage and being able to solve them before you incur any costs.

The cabinet below is laser cut from 12mm poplar plywood. The corner connections are glued and stapled.
Onshape is one of the many options if you are looking for CAD software, and definitely worth considering.