On occasion I find myself working with a design tool and thinking, "Man I wish this was my Ti-89." My trusty Ti-89 and I went through a lot of pain and growth together. One of the darkest days in my career was when I walked out to my vehicle only to see that it had been burglarized. I didn't get nearly as upset about my broken window nor the theft of my fancy new tablet... but did I ever pine away over the loss of my Ti-89. I tell you that tragic love tale as the motivation and leap in curiosity that lead me to create a workflow for a graphing CAD-culator.
Every now and then, I encounter something I would like drafted and think to myself, "it would be super easy to do this with my graphing calculator." The majority of those thoughts are just my subconscious trying to find a way to rekindle the lost love of my TI-89, but there is a nugget of sincerity to it as well....
So down the rabbit hole I have gone. Check your good sense at the door and lets take a dive into my graphing CAD-culator.
On this journey you will need to use the technique of dumping commands into a command line similar to what I did in the AutoCAD tip I wrote: Copy Pasta Command Line Edition
In that example I used simple text, but on this journey I knocked it up a notch and used Microsoft's Excel to make short work of the calculations and string handling. Excel lends its self well to this type of activity as it allows you to apply the parts and pieces of the AutoCAD commands to the calculations that you will need. It would be best if you have a decent working knowledge of using formulas in excel to accomplish this but the complexity really depends on what you are trying to accomplish. One excel function that you should definitely familiarize your self with is the Concatenate function. Another thing to consider when doing this type of thing is the kind of content you would like to create in AutoCAD. If you are needing line work you need to consider that your excel formulas and calculations need an X and Y for both starting and stopping points (see image below). If you are only using nodes or points all you need is an X and Y. If you are wanting to use a spline, this again requires a different approach in creating your excel formulas. Something as simple as a linear regression requires a decent amount of thought for initial set up, but once you set up your basic formulas these can be applied to more complex formulas.
This post will be light on written content due to the nature of what I have done. Below are some great images, but its more fun to get in and play with the formulas. I have attached a spreadsheet which houses some of the examples shown. If you are unable to get into the spreadsheet, immediately below is a screenshot of what setting up the formula may looks like and a small section of commands that you can paste into your command line in AutoCAD.
Example formula set up in Excel
Example Formula set up (Sin wave) Using Splines. This is what you would paste into the command line in AutoCAD
spline m cv 0,0
0.5,1.19856384651051
1,2.10367746201974
1.5,2.49373746651014
2,2.2732435670642
2.5,1.49618036025989
3,0.352800020149668
3.5,-0.87695806922405
4,-1.89200623826982
4.5,-2.44382529416274
5,-2.39731068665785
5.5,-1.76385081392598
6,-0.698538745497315
6.5,0.537799970219539
7,1.64246649679697
7.5,2.34499994193685
8,2.47339561655845
8.5,1.99621778155873
9,1.03029621310439
9.5,-0.187877801154523
10,-1.36005277722342
10.5,-2.19923939992918
11,-2.49997551637676
11.5,-2.18863043672107
Here are some examples of the cool geometry that you can easily create with this type of set up:
Exponential Curves
Sin Waves
Archimedean Spiral
Simple Fractals
Mobius Strip (note: needed to do a little more than just dump the commands in for this one due to the way I set up the formulas)
And a throwback to some of that childhood fun; Spriographs!
Its should be noted that these may not be the most efficient ways to get this geometry into a drawing, but it may serve as a good way to build the guidelines or frames on which you can base more efficient geometry.
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