I've never been any good with 3D software, Metasequoia, AutoCad, and Pepakura, but I can see they are very usefull tools. The Nautilus was developed mostly with Metasequoia, and Unfolded with Pepakura, but not by me. I had some help with that part. I use Microsoft Word for line drawing, and Paint Shop Pro 6.0 (PSP) for painting and textures after the 3d model has been unfolded, or as I know the term, rendered as a developable surface, aka, flattened.

Microsoft Word has a "Draw" facility that is very powerful. Along with having just about every basic shape you could want, each is an object that can be adjusted, cut and paste individually, A significant advantage to just a canvas-style environment. the files remain small too. PSP also has this object concept but at a significant cost. An object stored PSP file will be about 3mb per page. The MS Word version of my Saturn V, all 18 pages came in at 80K!!! Has to do with the Vector storage of the objects rather than a raster. Oh the best part of MS Word. Each object is also adjustable with exact length and width parameters. So, for example, if you want a circle that is 3" in diameter, you can rough draw using the oval tool, and then right click and set the height to 3" and the width to 3" and when you print, that circle is exactly correct. This was an incredible time saver as I have yet to find any other tool that is as easy to get exact measurements on.

The final program/tool I use is Ghostview/GhostGum. These programs allow you to capture an print image that goes to a printer, and then convert it to another usable format. So, for example, I make up my line drawings with MS Word, Then I capture the print image that the printer would get (remember the Circle is exactly 3" on that sheet and the print image is exactly formatted to the 8.5x11 sheet of paper.) I then use Ghostview to read the print image, and convert it to a jpg file at 300dpi. I then open the jpg file with PSP and low and behold, I'm looking at a image that is exactly 8.5x11, and the circle (no longer vector, but canvas style) is exactly 3" when I print this jpg at 100%. I now also have a canvas that I can add whatever textures, detail to and the scale is already set, and will fit on the printer.

Onto scale thoughts, Most of it is little more than Ms. Hinchley's 7th grade alegebra and geometry class, but without understanding it, I can see how it can be overwhelming.

Lets start with the Saturn V, its 363 feet tall. Well to scale it at 1/100, we multiply the scale bye the orginal value: 363 feet x 1/100 = 3.63 feet and to convert we can multiply by 1 (1??? any number mutiplyed by 1 is just itself isn't it?), but watch...

3.63 feet x 12 inches/ 1 feet = 43.56 inches.

hey isn't that cheating? no!!! 1 can be represented as any number over itself. Well 12 inches = 1 foot, so 12inches/1foot = 1foot/1foot = 1 so all I'm really doing is multiplying by 1. however when multiplying I have a "feet" in the numberator (think of 3.63 feet as 3.63 x 1feet, I know another cheat) and think of the denominator of the "1" that I created as 1 x 1feet. Now with the DISTRIBUTIVE law of multiplication, (Remember Ms Hinchley at the front of the blackboard?) the 1feet/1feet cancel each other out, viz, are just a 1, and multiply out. leaving the equation to just:

3.63 x 12 inches = 43.56 inches.

I know I played a lot of games, but "that's all math is, cheap tricks and bad jokes." (Professor Brown, University at Albany, 1984) a quote I have never forgotten.

Well take the above idea and you can apply it to any scale you want, 1/96, 1/48, etc. just substitute the scale you want for the value 1/100 in the above example. You can also convert it to whatever unit of measure you like by the "multiply by 1" trick, using like values of "1" eg, 2.54cm/1 inch, 3feet/1yard, etc...

On scale, 1/96 where'd that come from? A. architecture. 96" == 8', the standard ceiling height in American homes. Well, doing the math quickly this time, 1/96 means that every 8feet of rocket becomes 1" of model (you can check my math.) At 1/48, every 4 feet of rocket is 1 inch of model, aka, every 8 feet of rocket is 2 inches of rocket. Now we can see the relationship of scale to actual size, 1/48 is 2x 1/96, which corresponds with the fact that 2x 48 =96.

Well, to make a scale model, if you have all the measurements, (readily available with the rockets) It can be reduced to a simple calculation to get the scale measurements. So I put a excel spreadsheet together to do just that:

cone/scaledown02_satv.xls

edit 100619: it has come to my attention that the use of the cone-o-matic with microsoft word is not completely described, so here are some additonal examples:
cone/cone_make01.doc

It allows for you to simply adjust scale and units, and still have all the numbers you need.

Now, think about a cylinder, it has a height, and if you look at it from the top, it is a circle. Now take a pair of scissors and slice up the side, It unrolls into a rectangle. one set of sides of the rectangle are the height of the cylinder, and the other sides have a relationship to the diameter of the recently destroyed circle. Back to Ms Hinchleys class, the side in question represents the CIRCUMFERENCE of the circle, which has the formula,

circumference= 2(pi)Radius = (pi)Diameter where

pi is a very specific value approximately 3.1415. We'll skip the discussion on where the 3.1415 came from, but trust me on this. Well now the cylinders of a rocket, at any scale, in any unit of measure are a mere mathematical calculation away. With MS Word, I can now make the circles and rectangles exactly those dimensions, and,... get the idea?

In that spreadsheet is also a cone calculator. At this time it suffices to say that the cones are also just a math calcuation away, however, even Ms Hinchley would be impressed with the math needed for that:

http://community.webshots.com/photo/43834090/46799294tIAmyC

That set of equations, to accurately calculate the aft interstage based on its starting and ending diameters and it's height, took me longer to figure out than creating, building, and designing the rest of the Saturn V combined. But it was very satisfying to get it right. I reduced those calculations to another spreadsheet, It's included in the above spreadsheet on a seperate page, the one labeled cone-o-matic.

I even made the cone-o-matic into a html page:

cone/index.html


- Jon