A part of iterative design is that during the designing process, elements come together and inform how one of the other much change or can be better. If you design part A and within the whole and it clashes with part B then optimisations have to be made. Sometimes this process cascades all throughout the design which can be a hassle, but ultimately results in some optimum within the general design restraints.

One such part which has a major influence on just about everything else is the shell. Its dimensions dictate storage, freedom of movement, routing, manufacturing. On top of that, it pretty much defines the look and feel, so every few iterations of the frame and basic elements I fit a shell around it in CAD to see if everything still fits nicely within a nice shape. This informs me where I can safe space or where my tolerances are to strict.

Now there are a lot of things one can blame on illness, alas being bad at lofting and shaping in 3D is not one of them! I know my way around 3D software and have little issues designing rigid and mechanical models, but when it comes to flowing organic modelling I really suck. Still it is the best tool for the job, and doing multiple versions gradually makes me better, but I lofting wizard I'll never be.

I got the side view pretty much spot on, but I can not seem to get the curves and shape from the top view right. Here is my latest mock up to show what I mean :

This all seems pretty sane as a concept. It is a handy tool to see where things can fit. Of course many spaces wasted do to the loft, but as I said, I'm no wizard at this and a ballpark model i good enough for now. The problem is the top down view.

You can see it has quite a big bottom, but those dimensions are determined by the wheel base which is about 1 meter. This isn't a ridiculous base width for a delta trike at all, so the trunk/boot at the wheel arc level are fine. Higher up it gets a bit more bulky. I want this part to taper upwards as the rest does lengthwise. The restriction on this is the width of the solar panel, but at this moment I can't seem to make it less cube shaped. My sculpting eye does does not cooperate.

I also was a more gentle movement towards round at the top. This would allow for the from taper to be more spacious while also looking thinner. Also can't seem to get it quite right. These are quite important dimensions as they dictate a lot about the seat/mattress system, the steering system, the door and a myriad of other elements.

Perhaps you are thinking that this does not look all that fat, but realize this is the halfway cutaway. The full shell does not look fair at all. The seat is to big in places, the footwell seems a bit tight and there is little room for reinforcements for the door mechanism for example. There is ample space for storage though. I can bring a library, full camping gear and then some... Perhaps also not a key goal.

Well, that is where we are right now. A semi decent fitting structural body. I'll just have to keep hack and slicing away at it until it reaches maturity. I Think I'll do some detailed design work of the seat and steering mechanisms as these are also closely intertwined. Work a but more on the drivetrain and then seen where the splines land!