Fusion 360 for Boat Design Pt2

I am in the process of wrapping up my first boat from start to finish in Fusion 360. The start being my interpretation of the design brief, and the finish being the G code for the CNC machine (and of course construction drawings for the floor).

And as we are all so much cleverer in hindsight, I am only now realizing how Fusion is really designed to work.

The most crucial point is to follow ‘rule number 1’, which is to first create an empty component, or sub-component, before doing anything. As I reach the end of this project, any component that contains more than 1 body has become a problem. Of course there are ways to rectify this, but my life would have been simpler if I had just done it correctly first time round. I work almost exclusively in sheet metal, and having more than 1 sheet metal body in a component is particularly difficult to deal with when it comes to extracting flat patterns.

But overall I have been genuinely impressed with the resilience of my geometry. Here are a couple of examples:

After I had modeled up the hull, deck, frames, longitudinals and the cabin the project changed, I needed to make the hull 1ft wider. I went back to the sketch containing my splines used to loft my hull plates and updated the beam dimension. And while I held my breath everything as mentioned above updated perfectly to the ‘new’ hull.

I then had an issue with not enough deck space at the transom behind the cabin. And pushed all my frames forward. Once again everything behaved and took less than a minute to update. All my egg-box slots in the longitudinals for the frames also updated perfectly.

And lastly, after having done the weight study I lifted the deck by 2 inches. Once again flawless results. Very impressive.

I need to mention that there is 1 serious shortcoming when it comes to sheet metal. Whereas Inventor will allow you to unfold hull plates that have been created by a lofted flange, Fusion refuses to. There is a fair amount of noise on the user forum about this, so let’s hope it’s not a problem for much longer. I had no option other than exporting the part to Rhino (sigh) and using unrollsrf there. My current budget does not allow for Inventor unfortunately.

Up until now, my next step has always been to do a plate layout of all the flat patterns on a 2d drawing and export that to a DXF for nesting and cutting. This time I hit a problem. My more complicated DXF profiles would not export as closed, even though they were taken off the solids. There were small inconsistencies where splines met other types of lines, even when I converted the profile to polylines in Fusion prior to export. But I did hit a lucky break, it had to happen eventually! My client needed me to do the nesting, whereas I had planned on a plate layout. And as it turns out, this is something Fusion is really good at. I derived all my flat patterns into a new file (and of course they are all still linked to the original model) Created a new sketch to correspond to the plate size and hit ‘arrange’. A minute or 2 later all my parts were beautifully nested. I have yet to try the nesting extension, which gives more functionality such as automatically sorting the parts by thickness. But it does have a 7 day free trial, so I’ll give it a bash when I can make maximum use of those 7 days.

At the stage I am at, I now realize that the path of least resistance is to do the toolpath programming in Fusion where it will recognize all my profiles as closed. So I am pushing for that. One of the functions I am looking forward to is the trace, which I can use to do my plate markings. Not only from the bend lines already on the parts, but also from sketches on top of the plates. It’s always a good idea to help the factory out as much as you can.

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