Sultana build log – Part 17

I caught an error in my design. The bow former pieces end at a level that is too high. I corrected them and now they end flush with the forecastle deck level. I hope there are no other errors that I have overlooked.

Design correction for the bow former pieces
Design correction for the bow former pieces

Ok, let’s get ready for laser cutting. The laser cutter software is called RDWorks. It has some basic tools to create and modify shapes, but… Well, have a look at the message that appears at the bottom left of the RDWorks window. I think it says it all.

Message on the RDWorks program
Message on the RDWorks program

I tried exporting one of the bulkhead shapes from Fusion 360 as a DXF and importing it into RDWorks. There is a problem. Notice how the edges of the shape aren’t smooth and sometimes overlap.

This is not a problem with RDWorks. I found lots of people complaining about issues with the DXF export function in Fusion 360. Apparently, it outputs splines in a format that many other programs can’t handle.

Shape imported into RDWorks with ragged edges
Shape imported into RDWorks with ragged edges

The solution I found is a Fusion 360 plug-in called “DXF Spline To Polyline“. The plug-in adds a separate DXF export option to Fusion 360 that converts splines to many short line segments. Here is the same bulkhead piece exported using the plug-in then brought into RDWorks.

Once I confirmed that the plug-in was working as expected, I exported every shape (bulkheads, fairing lines, keel, rudder, transom, etc.) as a separate DXF file. There were 51 in all.

Shape imported into RDWorks with smooth edges
Shape imported into RDWorks with smooth edges

It was pretty clear that arranging the parts for cutting using RDWorks would be a pain. I found some strong recommendations for the popular open-source vector graphics software Inkscape. Learning the basic operations within Inkscape didn’t take long.

In Inkscape, I created a new document with a size equivalent to a 24″ x 4″ wood sheet. Then I imported a DXF and moved it into place. For items that will be scribed rather than cut, I set the color to red. Labels were adding to pieces using the text tool. However, in order to make sure they would be scribed by the laser cutter, I had to convert the text objects into paths using the Path -> Object to Path menu option.

When the whole Inkscape document is saved as a DXF then imported into RDWorks, RDWorks will interpret each color as a layer, so the separation between the lines to scribe and lines to cut is preserved.

Here’s the first sheet of objects. I will end up with four total.

Laser cutting layout in Inkscape
Laser cutting layout in Inkscape

While working on the layout for cutting, I realized that I’ll have some extra space. So I designed a cradle for the model to sit in while I work on it.

Cradle for the ship model
Cradle for the ship model

Leave a Reply

Your e-mail address will not be published. To prevent spam, URLs are forbidden in comments.