DB:
Thanks for your explanation of your system.

Jim

Your welcome.

But I can't help but feel that a lot is left unclear here. I find it is very hard to actually explain things like this in such a setting. It's one of those things that's best done face to face, where you can talk with people and do things right in front of them.

If you all have any other questions (not just Jim!) fire away. And if you have any challenges for me (specifications of a building for me to try my hand at) then fire away on that too!

DLB

DL:
I don't think that I'm unclear on your system. As of right now I don't have any further questions.

The whole reason why I tried it was to see if it could help me to design the correct roof pitch for this client's barn.

I have another one or two projects in the wind that may come about in a while. And if they do I may try your system to see how it will produce a frame design that "looks right."

Jim

My hope is to develop a system that can work well in conjunction with standardized measurement, meaning that we can create designs with it that are hybrid geometry and numeric. For this I can see a number of advantages. I hope that this system will accomplish this goal, which is part of why I'd like some more opportunities to test it.

One reason for this idea is that it sometimes makes sense for us to lay out the walls of our buildings using numbers. That way we easily can make a footprint of exact specifications. But when it comes to roof structures, particularly trusses, I believe geometry is the way to go. We can have numerical floor plans with geometric roofs. A big reason for this is the inherent beauty of geometric order. Another big advantage is the engineering value inherent in true geometric ratios.

And of course, there is the also the case of the fully geometric structure. The question always remains, what is its true value? Is geometry in this sense merely a novelty, or an advertising scheme? Or does it hold REAL value (other than, 'it looks neat')? These are important questions that we need to continually ask ourselves.

To me, the biggest advantage of geometric design combined with scribe layout is the total lack of numbers, and the resulting total lack of mathematical calculations. I like the idea of being able to pick up a compass and draw out figures that I would have to otherwise use complex trigonometry to get. And this is why I am a proponent of geometry for roofing. Design it with geometry, measure your drawings to fairly tight tolerance and let your computer figure out the numbers needed to please the engineer. The result is you do no math.

And I am not necessarily saying you are very unclear, it is just that there is a lot more to my systems than I am able to explain in this way. It is impossible to teach something thoroughly without actually being there. I think you have a good grasp of the system, but there are a number of complexities, and there is a certain art to it that can't be explained that can only be learned by seeing and doing.

DLB

It is common in Timber framing for the location of certain members such as braces to be related to other members by geometric ratios, such as 1/3. Normally this is come at by dividing the measurements to get the right number. That stinks. That is especially annoying when the measurement is not easily divided. The third is an especially troublesome fraction, since inches cannot be easily divided into true thirds mathematically.

Geometry gives us some easy methods for getting at these simple ratios without having to strain our brains. Indeed, once we are used to the simple steps involved it is like second nature.

The major advantage of designing a frame from the outset with geometry is that, as a result, these fractions are often already found for us.

Which brings me to this, on my rendering of Jim's building I made a mistake. For the brace length I took a length off of the figure that 'looked right' when in fact I should have used my compass to divide the post length to get a stronger brace to post ratio. A simple error, made by forgetting the principles of the system I was using. Oops.

I won't hold that against you.....