The Journal of the Wandering Engineer

How Not to Model an Appropriate Technology Project us

[tl;dr: When modeling a complex project, let the sketchup model stand alone and speak for itself during the design process. Wait until the design is very well gelled before getting into drawing and construction process drawings.]

The open source lathe project I’ve been doing modeling for recently launched the first version of the build manual. I’m writing this post to collect my thoughts on the process and communicate some extremely valuable lessons I learned.

lathe1.png

When I signed on for this project, I honestly thought it’d be a commitment of 2-4 weeks. Six weeks, maybe, if I got ornate.

(Heh. It’s now month 8?)

How I Thought the Project Would Go:

Model the lathe in two weeks > set up cool drawings > write the manual and format > publish in a couple weeks > woohoo done!

How the Project Actually Went:

Model the lathe > set up a couple cool drawings > design change > tweak the model > cool drawings now outdated, so redo > design change > remodel > design change > remodel > get halfway done doing cool drawings > major design change, scrap the entire model and start a new one > start new dra– > design change > design change > remodel > hey, guys, c’mon, just let me– > design change > seriously guys not funny > design change > drawings > etc etc…

This isn’t a dig on Pat or anyone else, it’s my mistake for not acknowledging the true nature of projects like these and adapting quicker to the stage of design I found myself in. My error was in thinking that the design was more or less done. The reality was that the project was still going through conceptual design.

Sketchup is a super simple, quick tool for modeling design ideas and it actually handles complexity well. It’s suited for projects like this where a lot of changes need to be made and explored and the design is dynamic.

The drawing creation program paired with Sketchup, Layout, is supposedly a two-way street. That is, you can set up a drawing in Layout (say, a longitudinal section through the model, or an exploded view of a component), go back and change the model in Sketchup, and the drawing in Layout will update.

[It took me about 3 minutes to cut and dimension this section within Sketchup.]

[It took me about 3 minutes to cut and dimension this section within Sketchup.]

Will this is technically true, it didn’t work out that seamlessly. Part of this has to do with my skill level: if I was better at organizing complex models using the Outliner, Layers, and Scenes, it would definitely have gone smoother.

But I maintain that even if I was a master of the outliner, drawings set up to communicate the progression of construction of a complex machine would not have survived the couple major and numerous minor design changes. At the very least, it would have required a lot of maintenance work for not a lot of payoff.

The real issue is that I was doing things out of sequence. I spent a lot of time setting up both technical drawings and construction process drawings, and then redoing them, over and over. In retrospect, my time would have been better spent just doing modeling work.

The beauty of Sketchup is that you can transfer the Sketchup file itself and the program is intuitive enough to operate that anyone can quickly open it up and see what’s going on: for design review and collaboration, no 2D drawings needed. Just upload the model! I was wasting time trying to produce communicative 2D drawings when the 3D model spoke for itself far better.

How I Should Have Approached the Project:

Model the lathe > review > design change > remodel > design change > remodel > design change > remodel > [etc etc] > remodel > wait for it…. wait for it…. > make drawings and insert into manual

The way the manual is coming together now, where Pat is cutting in screenshots from the living model file itself, and I’m adding other shots here and there, while not the most polished, might be the most appropriate way to put together the start of this manual – especially since there’s so much back and forth going on. It’s relatively simple for me to play with the model, try something new, snap a few screenshots off or even transfer the sketchup model.

[About a minute to dimension and export this image, no Layout required.]

[About a minute to dimension and export this image, no Layout required.]

In retrospect, the next time I jump into a big modeling/design project, I’ll be sure to spend most if not all of my time just with the model, and not play around with setting up polished images at inappropriate stages of the project.

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