Of course the more I think about this, the more questions I seem to have.
One is why did you pick this distance shown in red on scan11-A as the distance to use to figure the roof height above the tie beam? or distance D-H.

Jim,

My drawing are semi-measured. Meaning I measure what the figures come out to in inches so I know the general area of what they will measure out to. It is a useful reference to have.

So here, the choice of dimensions used was similar perhaps to your choice for your original measurements. Why did you choose 10 feet for the tie beam? why did you choose 4 feet for the knee wall?

I chose my measurements largely because those are the ones that closest matched yours, and also are the ones that made the most sense to me at the time.

Hope that helps

DLB

Tim, I can tell you what the results will be because of the fairly straightforward proportions of this building. With the two 'petals' aligned with the tie beam, the other will line up with the queen posts. That is simple, because the queen posts are located at the 1/4 and 3/4 locations relative to the width, which is where the petals would also be.

The daisy wheel always divides a given space into fourths.

The question, however, is what happens with the daisy wheel when you draw in the hexagram...

I should explain something about my figures and the trend of my geometries.

My geometries have been trending away from arcs and circles and more toward a series of lines to create geometric figures, and there is a very valid reason for this.

If I am performing the geometry at full scale to create the scribing layout itself, I may not always be doing so on nice smooth-troweled concrete. I may be doing it on uneven ground, possibly complete with grass and other obstructions. As such, there is no good way to accurately draw arcs and circles.

And it is important to note, when performing geometry the smaller scale it is done on, the more prone to error it is. A small drawing the size of drafting paper can often times have noticeable and measurable errors that arise simply as a consequence of the thickness of pen lines or one minute misplacement of a compass point. For this reason, I am insistent that geometries should be totally redone at full scale to ensure things come out as intended. The shop drawings serve their purpose, but it is not to be used to get any final measurements for anything.

This figure was designed so that it can be easily done with a length of rope on the ground to determine the points. It is not necessary to actually mark a single arc. It is the culmination of all of my efforts, but was arrived at largely by accident. I made it on one of my drawings while trying to arrive at a certain proportion (which it yielded). After studying what I had just done I discovered it was exactly what I had been trying to develop all along. With a few minor modifications and perhaps a little increase in its complexity, it can give you just about any proportion you could want. In its simplest form as shown here it is more than sufficient for most applications.

One important thing to consider is that it is often helpful to actually make this figure multiple times, as for different parts of your structure you may want to use a different base number. For example, I designed a building with it where the gable walls use a figure with a slightly larger base number than that used to design the side walls and floor plan. But the number for the gable walls is ultimately derived from the figure used to design the side walls and floor plan. Thus they are all still related by the geometry and are proportionate to each other.

It may even be useful for complex frames to have a number of figures derived from each other. But any one part of the frame should be limited to the use of a single figure to keep it from becoming too arbitrary.

Now I would like to see more people do like Jim, and try their hand at applying these techniques to their own projects.

I am working on a frame right now designed with this system. As soon as I can figure out how to get up good pictures of my large shop drawings (the lines dont show up well on my camera and they are too big to scan) I will try to post some up for demonstration. IT may be some time before the plans are totally finished however.

DLB

In reply to Tim's request for rotating the wheel.

I can and did but I can't login to photobucket right now. Something is wrong with their site, I think.

Why did you want me to show that?

Jim

Ok, well I stated why I used the dimensions I used; as they were the requests of the client.

The reason why I asked you why you used the lines you used, was I was trying to understand and learn your system so that I can use it to design other width frames.

If you had a reason why, such as "this is how they used to do it." Then it would make sense to me. If you are inventing or establishing a "new system" based on what you know of the old way of doing things. That's fine too, I'm just trying to understand.

You said you just picked one that somewhat matched my design. That was good and I now understand that. But what I'm looking for is a system that we could use every time we want to design a frame that "looks right."

If line D-H is the line to use every time, that's also good, I'll do that. But I thought you were trying to teach a system to use over and over to do it every time.

I'm willing to learn, and I wanted to understand the reason or the basis for using a line length for determining other building proportions.

Jim Rogers

Jim,

My procedure is to choose lines that are of a dimension in the area of what I want. If I want a height of 8 feet for example I will choose a line that approximates 8 feet on the diagram. This means I do I have scale for my drawings and I do check the lengths of certain lines with a ruler to see if they fit my requirements.

I chose line DH, for example, because it would result in a roof pitch close to what I wanted.

In the case of your design, your dimensions were based on customer specifications. In the case of my version of it my dimensions were based on your specifications.

We can design buildings using geometry to meet our preconceived specifications just as we can with inches and feet. It's just our measurements will end up relating to each other in slightly different ways.

We don't always have to use line DH as I used it. In fact on my shop design that I am working on my roof pitch is arrived at by much different means, as there is no dropped tie to base the roof height off of as I did here. I simply chose a starting point and a measure from the half wheel that would place the peak in the right spot.

For this it is necessary to have a building's general design already in mind. You need to know how high your walls are going to be, what you want fora roof pitch, where you want your braces, etc. Then you simply choose dimensions off of the figure that will yield the proper dimensions. It is no different than how we do things with a ruler. We know about where we want things to lay, so we force them to adhere to our standards of measured because we have to. Here we instead force them to conform to the measures yielded by geometry.

If we instead want to design a building that flows totally out of geometric forms, this is not the method to do it. We must instead apply the complexities of the Ad Quadratum and Ad Triangulum systems. But if we know what we want, and just require a means of arriving at exact locations and dimensions than this is the system. This geometry is a replacement for the measuring tape, to be used by an architect who already has a good idea of what he wants his building to look like.

Hope this helps

DLB

The problem with the daisy wheel as most people use it is that it is overly demanding. Its simplicity often times robs us of the ability to make frames as we want them to be. It is a great tool if you want to make a simple frame that follows its limited geometries, but it falls short when freedom of design is required. If your client does not want one of the few simple 'daisy wheel frames' then you need another tool -either to complicate the wheel to get what you need or a freer geometry from the start. That is the reason I have this 'half wheel'.

Simply put, the purpose of the half wheel is to provide a geometry that can be used like a measuring tape, a means of meeting out dimensions.

That said, I am not anti-daisy wheel. I like it. I use it. Sometimes I scratch it into a board here and there when thinking (or bored). It has its uses, but there are times when we need another tool.

My geometries arise out of an attempt to discover how man might have created buildings to suit his needs, to fit specific situations, etc. when he didn't have a standardized measurement, a square, and when the Daisy Wheel just wouldn't do. This is an attempt to explore how we might create things without measuring tapes. Take it for what it is worth, you may decide just to stick to your measuring tapes and that is fine.

Geometry should not be viewed as a science. It is not a set of rules like 'you must use line AB for such and such, line CD is to be used for this... etc. Rather it is a free art. You use the lines of geometry to fit your vision, or in a business setting to meet the demands of your clients. For my shop design I needed a plan approximately 14x24 feet with walls about 8 feet high. SO I set out to get dimensions close to that from my geometry. With a base 3 half wheel, I was able to achieve those exact measurements. I didn't get them because geometry made me do it. But rather I got them because, trough the geometry, I could.

Interestingly enough, the inspiration for the creation of my 'free geometry' concept where you transfer measurements instead of performing increasingly complex geometries came from a fiddle...

DLB

Tim:
I was able to login today.

Here is the drawing you wanted me to post.

Jim