(You guys might end up sorry you keep encouraging me, on this project? ... in other words, here comes a long update!)
Here's another photo-update, on my recent progress on this project or exercise. I tried to make the images as fairly self-explanatory as I can, but given some unusual concepts, I will have to throw in a lot of words that pictures can't describe. But without images, lots of what I'm hoping to get across, techniques-wise, would be "huh?" stuff, with or without words, so ...
The image above shows a scan of a contour gauge, as purchased from a local hardware store. They're common enough items, in such places. If you're not already familiar with one, or how it works, it's basically a lot of same-diameter and same-length metal rods or dowels, lined up next to one another, in a housing that allows a person to capture a 2D cross-section (or a profile, or shape, or whatever a person wants to call it) in both positive form, and negative form, at the same time. This one's made by a company called General. The markings on the device says it is "Made in USA" and there is a model number of 837 listed on the housing.
In this image, I sort of "circled" ("rectangled"?) the relevant portion, so it's less confusing. Due to the size of what I'm working on (both the foam "half-hull" test model, plus the wooden ninety-degree-angle device) part of the contour gauge has to hangs off of the edge, so, ignore the non-circled part. What I'm about to show, in the next image, might clarify my meaning.
What I'm showing in the last of these images, for today, is how I do things and what I use, to transfer each cross section drawing onto paper. Seen in this next photo (besides the half-model and the wooden thingie, and the stuff it's sitting on, including a mouse pad, to prop up the gauge from below, like a pillow, for this photo) is a standard 3-inch by 5-inch index card; the contour gauge; a mechanical pencil with a 0.5 mm diameter drawing "pencil lead"; a partial, somewhat dirty pencil eraser of the rectangular type; a (green) long-style, click-type pencil eraser; a small 90-degree square; and a "clay shaper" which is sort of a paint brush (kind of) that has a molded silicone tip on it.
The erasers and the clay shaper are used to gently push the individual metal rods or wires down, a few at a time, onto the model's surface. It's a trick I wished I knew, years ago, so I'll explain what's going on, with that.
When I first began using a contour gauge, more than a few years ago, no one really showed me how to use it. I had presumed that pushing the whole thing down, at once, onto the surface of what I'm "measuring," was the way to go. Not exactly. The rods are thin enough in diameter that they'll bend, individually, or maybe even try to sort of push the ones next to it, sideways, at some bizarre angle, if a person pushes too hard, to make the individual rods match up perfectly, with whatever's being "measured". It's way too much pressure, exerted on way too small of an area (pounds per square inch, etc.) if you push the whole device down, like you're using it to cut through a block of cheese, or something, instead of whatever you're trying to carefully "measure". Your best results will be if the rods all remain in perfect side-by-side alignment with one another (parallel) and if the rods all remain perfectly straight. So there's some care necessary, with this.
Over time I have found (by lots of exerience and occasional experimenation) that it's more accurate, by far, to gently hold the ends of a few such rods, with my thumb and fingers, as a first step. I'm not pushing on the rod's back end. I'm gripping the last portion of the sides ("faces"?) of the rods, a few at a time. I'm gently pushing them, into the approximate shape of whatever is going to be "touched" by those rod ends. Maybe I'll have it all adjusted, to a tolerance of approximately an eighth of one inch? (Give or take.)
When the rods are all nearly touching, I gently and patiently press down a few rod (ends, this time) using one of the two erasers, then the tip of the clay shaper, to get closer to where everything is as perfectly lined up as will ever likely be the case.
Another thing this last image, above, is meant to show is that it's really a handy thing to have some sort of a flat surface, to lay the index card on, for the purpose of tracing the shape of the (negative or positive) half of the contour gauge's data or information. It's also handy to be able to press teh top of the index card upwards, until it hits the fatter housing area, on the contour gauge. By touching the top of the card to the bottom of the housing, while having the contour gauge and the card sitting on some flat, usually-portable surface (a clip board also works well for that purpose) you eliminate some possible wiggling around, of the card versus the gauge. If you realize you didn't quite trace the whole line (sometimes it feels like you did, but the mechanical pencil's lead was too short, or what have you) it's a lot easier to put the card and the gauge back into alignment with each other, if you're using the system or procedure I just described. It's far more of a repeat-able process, that way. One less set of things to worry about.
Some things I'll mention, that relate to the "why" of all of this (ultra?) nerdy silliness, rather than the "how" of it:
I did this "lofting off of the lines" of the test model, twice: initially exactly aligned on the Sharpie lines I drew, in prior steps. That's all "as planned" all along. Then, some days later, after looking for a while at how much things had changed, shape-wise, from one (vertical) "slice of bread" to the next one (if you can imagine it, from front to back), and also thinking back on how no damage got done to the somewhat delicate foam test model, I shrugged and decided to "double the resolution" by eye-balling some new Sharpie lines onto the model, halfway between the existing (vertical) lines. I used dashed (not solid) lines to indicate the "point five" positions: that is, the "and a half" stations. So if I had initially marked (say) the peak of the front fender as being "station five" (or "cross section five") then the new line right in front of that (towards the car's front end) would be "4.5" and the one right behind the fender's peak (going towards the car's back end) would be "station or section 5.5" -- but that's kind of arbitrary, in a few ways. I chose to start counting, in reverse, numerically, at that high point or that peak, and moving forward. So, initially, that peak had a temporary number of one, and I could see it would take five "slices of bread" to complete the final model, from that peak, going forward.
There's a lot of "making sure I'm not messing myself up, later on" sorts of "reality checks" that are necessary, to do things as I'm showing, here.
With the three-eighths-of-one-inch balsa wood slices I pictured using, there would not be any weirdness -- (like needing a tiny extra bit at the nose's tip, when shaping of the final model began, using "slices of balsa / bread") -- so I knew that starting at the peak of that fender was a good choice, since it's the natural high point of the model's front end. I could have laid out the first vertical line pretty much anywhere (from front to back) but by picking the natural high point, I avoid shaping guess-work, later on. Anything "down hill" from that point, on either side, becomes a "just cut a bit off, at a small angle" sort of thing; not "did I cut too much off, and now need to add on?" kind of thing. (It makes sense if you actually try this stuff -- trust me! But it's hard to explain. It's kind of like picturing "negative spaces" while looking at a positive form, in that it's mind-blowing, early on, but with more and more practice, it becomes second nature.)
Anyway, part of the reason for my having measured the "whole numbers" first, and then, later, the "fractions" between the whole numbers, is that the precision of the slice-cutting, and the amount of guess-work that needs to be done, during the "assembling the carefully cut-out slices of bread" rises with the number of bread slices. Doubling the number of "bread" slices used, overall, means a lot less eye-balling or guesswork, from the peak of one slice (which is only going to be "true" on one face of any given "slice of bread / balsa") to where the next slice's face says you have to cut off, at some unknown angle, some portion of that slice's "crust". Simply sanding the whole thing down, until all of the 90-degree peaks (crust) is gone, is not going to give the shape you want. One face of each solid "slice," as I'm doing things here, is actually 100% correct, in cross section, right from the moment you trace the shape onto that slice's face, and cut the slice out.
Something I take for granted, that folks who don't use this method may not immediately understand, is that a lot of the benefit with doing things as I'm doing them boils down to this: one face, as cut, if you cut it out to the exact lines I'm "lofting off" of the test model, is perfectly shaped, as-is. The other face of each future slice usually needs a little bit of adjustment -- just a little, though -- so that the "correct face" of one slice matches up well with the next "correct face" of the next slice. (This part will make more sense, at a later time. I'm sort of explaining myself, now, since it probably looks like I'm wasting time and energy, getting things too clean and perfect, early on. But it's not wasted -- it's something that "pays off, handsomely, later".
Try to visualize this, if I'm not making enough (or any?) sense ... from the fender's peak (as seen from the side view) and moving forward, on the test model: if you count the Sharpie line at that vertical peak or "fattest point" as the glueing area between two future (solid) slices, then the rear-most face of the forward-most of those two solid slices, is already 100% correct, "as cut out". Zero need for tweaking or adjustments, there, on that one face. The one face forward, on that slice, however, will need a tiny bit of a tweak, however. And the rear-most face of the slice in front of that one, will tell you how much of a tweak or adjustment is needed. Same basic idea with the slices, behind that vertical peak: the highest point, and thus the most-correct face, on that slice, will be the forward-facing face. One slice behind the initial pair, will take a tiny bit of adjustment; also guided by what the very-carefully-cut-out batch of slices says is correct. This may sound like a tiny thing, but it's not, because at various points on each slice, the amount you have to "adjust" changes (or could) depending on where you are, on the outline of each slice (if viewing it's face, "head on") ... to stick with the two slices on either side of that fender's highest peak area, the peak itself is nearly flat, at the visible peak, itself. But towards the hood's center, it's dropping, wildly, and curving, at the same time. So more will be necessary, adjustment-wise, towards the center of the hood's area, than at the fender line's upper peak. In some areas around there, it's dropping about half the width of a 3/8ths-inch slice, in one slice (!) while being almost a flat line, at the hood's center, and at the peak of that fender's line.
Darned hard to get all of that stuff correct, if it's a really swoopy / complicated shape, if you are "eyeballing" too many things at once.
Symmetry is MUCH easier to get correct, with this method!
But, yeah, it takes a lot of careful measuring and stuff, to "get there".
Having done this process a bunch of times, on other models, in the past, I know it's just SSSOOOOOO much easier, overall, to spend (seemingly) WAY "too much" time, early on, on a test model (in half-hull form) and then carefully "measuring" that early model, than trying to "reinvent the wheel" at some later point, if/when someone says, "Hey, that looks great, and if you're willing to share your drawings, I'd like to build that form, too ... but I want to build mine at half-size (or at three times the size, or whatever)." When I was perfecting (?) this set of processes, years ago, I kept wanting to quit, or hurry up, or whatever, to "get a real model done" ... but I kept forcing myself to be patient. What usually did the trick, as far as forcing myself to "keep my nose to the grindstone," back then, was this thought: if someone told me, "Hey, great, build me three of those, but in three different sizes" -- would I be looking for a bazooka, to express my appreciation (ahem!) for that request? Or would I shrug, and do it, with no worries that I'd be frying my brain's cells, due to worrying about if each model was going to be a fine visual match for the other possible models?
That in itself was an off-shoot of something I would ask guys, who built mostly military models, back when I was hanging out with such guys, a bunch of years ago. I'd see them listing all they did, at some contest, when a buddy asked them what they'd done to kit XYZ to make it be "contest worthy" and they'd inevitably describe the work load as "I just did a little bit" ... but the list they'd give, would fill half a magazine, if it was typed out! Because each task they'd done was in their comfort zone, and they were super-patient guys, I think they really did see it as "a little". I asked one guy, though -- a good friend; not a stranger -- why he and so many other guys always said "a little" when they meant "huge amounts" and he hadn't really thought about it, at all. I told myself to not describe tons of work as "a little" but, until I came up with that idea of "repeat all that you did, three times" idea, I didn't have a handle on what "little" really was, as compared to "a lot" or "a ridiculous amount". Hence moving, later on, the bulk of the work onto the first-ever test model; and "measuring" it. From that point on, yeah, there's a lot less "am I doing this correctly" worries.
Sometimes, at least as I see things, the intent of the maker is critical. If you buy a "garage kit" or a short-run kit that's not clear, on that intent, it's a lot less likely to be either be completed, at all; or satisfactorily completed.
Hopefully the benefit will become clear, later on, if it's not clear now ... but as I see it, by doing things in ways that are similar to what I'm doing here -- the careful definition, in 2D, of many cross sections -- one guy can sort of "take one for the team" in coming up with a set of working drawings that, later on, others can (potentially) use to create something new and cool.
Where it really gets wild is the potential of "blueprint bashes" ... which I haven't done a ton of, just yet, on any project, but the idea there is to start with (say) two different drawing sets, of different subjects, and to "invent" on paper, in 2D form, a hybrid that's halfway between those two subjects.
I'm getting way off-topic, so I'll shut up in a moment, but in between some of my past magazine articles, when I was writing for Sci-Fi and Fantasy Modeller, I did work on one such project. It felt incredibly freeing! Why? A person who is used to "thinking in 3D" can, with some practice, skip the whole "sculpting a new shape, from scratch, in 3D, and fine-tuning it all over that form" steps of a project ... and can do initial design work on paper. It is even easier than working with a 3D model, to get the initial profile cut out, in 2D form, from something like a side view; similarly design the top view; and from there, cut out some foam slices, and shape them in 3D. It doesn't even have to be a whole project, like a space ship or a car: two cool looking gas tanks for a motorcycle, that aren't really the scale you need, could result in a third, right-sized "hybrid" tank.
Anyway ... shutting up!
Apologies if I'm over-talking, or "over-selling" the how-to-or-why ideas here? I guess it depends on any given reader's interest levels, as to whether or not I'm over-doing word count, amount of pictures, and so on? I'm excited about the techniques, and am trying to share them, with others, in hopes that either sub-assemblies or full-on models might result, later on. It's all offered in a "food for thought" kind of way.
