So, I enjoy creating front ends to automatically generate cadd drawings for me. It’s like a lucrative hobby. I started doing it in the early 2000’s using Visual Basic 3, Microsoft Access and AutoLISP. Not cartoons, mind you. Anyone can distribute a generic drawing with notes. That’s not what I’m talking about. A front end so that anyone without cadd knowledge can create a fully vectorized 2D drawing made in seconds and accurate to eight decimal places. I have hundreds of front ends that I use when I need to. I can surely feed it bad data, but it’s faster and never forgets to carry the two. It’s such low-technology, any version of Autocad will do. I still use my version 2010 at home, but they all work with version 2023.

Here is part of a video showing one of the front ends in action (though the audio had to be removed). This is a custom front end in Visual Studio 2007 (with my ultra nerdy paint dotnet/autocad graphics because they refused to give me photoshop) that accepts user inputs for a finished drawing of a self-supported brick dome. The calculations for these domes, if doing manually, takes about an hour per course and domes would tend to average about twenty courses. This required three days worth of math you had to write out for your checker, and then one more to actually make the drawing and bills of material. Checking took another day in most cases, so essentially a week to get a quote out. I changed that process to seconds.

In the video, you see the data entry for the dome geometry and skew line (the base the bricks rest upon) Then, the brick shapes permitted to be used are defined by their chords. In this case, it was a 9x4.5x3 series set of up to five arches and wedges in each of two keys. When used as intended, they create a 9" thick spherical dome. It calculates the best fitting key (4.5"-4.5" or 4.5"-4") and then calculates a three piece combination of arches (3" on the outside tapering to up to 2" on the outside) and wedges (also 3" on the outside tapering but up to 2" on the inside) in a ratio that best forces the ring to close. It then iterates over the courses from a specified starting end until it completes naturally or the geometry becomes a mismatch for the bricks turning potential at a certain spherical radius.

It then creates two reports, a count report and a math report (all engineering documents required checking at the time.). BUT (here’s the nerd coolness) it remembers ALL that glorious data it did during the calculations, and builds a custom lisp file with it, which can then be run on an empty drawing to generate the full vector content, as you notice, pretty quickly. To fully check it, I had it generate a top, front and bottom view as well as the brick count in a handy dandy lil chart. It overwhelms the lil laptop I had to use as it draws EVERYTHING except dimensions (though I would eventually nail that down too). I perform the generation process twice, slightly changing the skew to achieve a different combination.

As a note, the drawing portion became the actual check. You will clearly tell if there is a problem with tilts and closure by just looking at the finished cadd vectors since they do capture the bricks real world symmetrical posture. The math report itself generates a series of checks to ensure the count is appropriate. Volume check, four-point circumference check, key checks, anti-straight checks, negative quantities. Lot’s of crazy things happen in the formula when the bricks aren’t able to find a valid solution to the geometry.

So, I think I make a valid argument that when used properly, AutoLISP is possibly one the best tools an Autocad designer can employ, and it has the potential to outperform any modern cadd program that’s packed with features you’re paying for but never using. In the time it took you to read this, CREO and Inventor are likely still booting up, and Solidworks is having license issues again.