CAD

George thought that if he could draw it he could build it.

Rhino 3D 2.0

Rhino is a 3D CAD program that is especially good at modelling compound curve surfaces to engineering standards. Now at release 4.0, Rhino has crept up in price, but the free evaluation copy will let you save 25 times.

Rhino uses drawings, bitmaps, digitised inputs, or dimensions as the basis for accurate curves, which can be turned into a surface or solids and rendered to check the look and feel of the final result.

Inputs

A 3D view blueprint was loaded into Rhino as a bitmap and scaled to the known dimensions. Profiles were taken from a 1/43 model to bring the blueprint to life.

Wire solder was folded around the model's cross section then popped into a flat bed scanner to create bitmaps that could be loaded into Rhino. Digitising or microtoming the model would have been more accurate.

Wireframe

Rhino has advanced tools for editing curves; just as well because the bitmaps took a lot of tracing and finessing to get right.

Surfaces

The curves were skinned by 'lofting' a surface over the curves. Again more finessing: if the skin was too tight the body resembled a starved horse; too loose and it was Mr Blobby.

Various panels and voids were added using additional surface extrusions as cutting tools to split the body where needed. (For example, cylinders were used to poke the eyes - ok, the headlight shells - into the body). The head fairing and engine cover required complex offsets and tapers as well as blending and lofting of surfaces. Just like virtual Plasticine. After 50 attempts, a model of the RS60 body shell emerged.

Beauty is skin deep. Ugly goes all the way down.

With the CAD bodyshell complete and dimensionally correct it was possible to layout the internal components and be confident that it all fitted together. No cutting, fitting, swearing, bashing and throwing away. Even better, the CAD produces a blueprint, cut list and an approximate weight.

And finally a 3 view plan that is useful.

All nicely stored in a CAD file. But can it be turned into reality? The Next Step beckons.

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