It’s several years since I made my 3D-printed model of a Broad Gauge 12t Coal Wagon.  In that post, I wrote “According to the [Broad Gauge Society journal] ‘Broadsheet’ No.9 … 'The main feature is a standard under-frame applied to many different types of wagon such as Van Trucks, Rail Trucks, Tilt Wagons and Box Wagons etc.'. This will encourage me to make other wagons that can make use of this common chassis!”

 

As it happens, @David Bigcheeseplant has beaten me to it in modelling this range of wagons and he has created some very fine 3D models of some of them. Nevertheless, I enjoy a challenge and one of the vehicles was a somewhat ad hoc conversion into a lime truck. The conversion involved adding a corrugated iron curved roof with sliding door to the basic 5-plank wagon body.

 

A rather faded Drawing (no 5674) shows this conversion as a 4-plank wagon but with an added note that “The Tracing taken of this for Lime Truck was made 3’-0” deep in place after 2’- 6” shewn on this Tracing

[sig] Aug – 1854”.

Based on OPC/BR Drawing 5674

 

Writing in ‘Broadsheet’ No.8 about 1850's IRON AND WOOD UNDERFRAME WAGGONS, Mike Jolly commented that this drawing is “As 5665 but drawn to shew corrugated iron curved roof with sliding door.

Good value at two for the price of one!” Since drawing 5665 is of the 12t Coal Wagon that I have already modelled, I felt it should be easy to create a new model by making a few simple additions.

 

In practice however, I had no idea how to create a 3D model of the curved corrugated iron sheets by means of Autodesk ‘Fusion’ – time for another learning curve!

 

A web search gave me some ideas; in particular a YouTube video  by ‘digitalDovetail’, which is actually about making a corrugated lampshade but contained all the elements that I needed to understand.

 

This post is, therefore, mainly concerned with how I created a corrugated and curved roof panel. Once that was done, I simply added it to my pre-existing model of a 12t Coal Truck.

 

Creating a Corrugated Curved Panel.

 

The following is an aide memoir to help me, in case I need to do this again!   If you know a better method, I’ll be pleased to hear about it.

 

UPDATE 14-10-2024   I have revised my method by using the 'offset' tool after Step 1 and then extruding just a single corrugation along the path, as described at Step 6. 

 

I find it is easier to use the 'rectangular pattern tool' on the solid body of a single corrugation, rather than on the drawing, as originally described.  The array of bodies is easier to match and join together that the array of drawings.

 

I have seen videos about how to create flat corrugated sheets but the special feature of this roof is that it contains curvatures in two orthogonal dimensions. To achieve this, I required the ‘Fusion’ ability to make three-dimensional (3D) sketches; this option needs to be set in the ‘Sketch Palette’ list of check boxes.

 

My first step was to sketch the end -profile of the corrugations. For this, I used the ‘spline’ tool, as suggested in the ‘lampshade’ video referred to above. In the first instance just one ‘corrugation’ needs to be drawn. This can then be duplicated along the length of the roof panel by means of the ‘Rectangular pattern’ tool. These two steps are illustrated below:

 

 

Note that there may be small gaps between the duplicated segments. I found by trial and error that the best approach to linking them together was not to try and do it by eye – i.e. by dragging the horizontal arrow until they seemed to overlap - but to bring them close and then zoom into the view and grab the end of one segment with the mouse and drag until it locked into position. The software then automatically adjusts all the segments into a single unit. I struggled with this for some time, since the next step only works when the segments are joined correctly.

 

Now it’s time to create the edge profile of the roof, for which I used the ‘offset’ tool to create the ‘thickness’ of the roof panel. I then used the ‘line’ tool to join up the end of the two paths, in order to create a closed ‘profile’ for the side of the roof.

 

 

 

Once I had formed the side profile, I needed to extrude this along a curved path to form the ‘arc roof’. This requires a ‘path’ to be defined across the width of the roof. Initially I drew this path in the same drawing plane as the edge profile, as show below:

 

 

Now I needed the 3D sketch capability in ‘Fusion’ to rotate the arc-path for the roof to be perpendicular to the edge profile:

 

 

Finally, I used the ‘Sweep’ tool to extrude the edge profile along the arc path, in order to create the 3D body of the corrugated roof.

 

 

I now had one segment of corrugated iron roof, which I duplicated to place two sections at each end of the ‘Lime Truck’.  The centre section of the roof was relatively straightforward, involving simple extrusion of a curved roof segment for the central sliding portion, which I have assumed to have been canvas covered.

 

All that remained was to add these new components to my existing model of the Coal wagon:

 

 

It’s an odd-looking vehicle – I keep seeing it as a very low van – but I expect it served a useful purpose at a time when most goods were carried in open wagons.

 

Top view of my Lime Truck conversion.

 

Mike