You can always mock some stuff up and try it out in PrusaSlicer to see how long it thinks it’ll take?

Wall thickness potentially depends on the size of the object? I guess 2mm would the the starting point, fill one with soil, see how sturdy it feels. Complexity for 3D printing is “free”, kinda. A lot of the best container designs incorporate ribs to strengthen them without using up too much material. Given that the joins are the weak part, you’d potentially want that a lot thicker.

You also want to look at “vase mode”. Some of the fastest printing objects you can get on a 3D printer are where you design around the constraints of vase mode and then you can use a fat nozzle with thick layers to print really fast.

You can always print plumbing instead of using PVC pipes? I’ve definitely seen self-watering pots such that they just have a pipe incorporated into the design such that it just sticks up along the corner. So, worse case, each module has a watering port. If you want to get fancy, you could make a manifold such that a single pipe sticks up in the middle and fills 4 reservoirs, although the fancier the plumbing the more likely you are to have one of them get dried out faster unless your filling routine tops them off.

Yeah, see if you know Python, then OpenSCAD is not a hard jump? One of the reasons why I really like OpenSCAD is that libraries like BOSL2 have parametric joiners and snaps and stuff. And you could totally write modifiers for FreeCAD or Blender to do it, sure, but it’s a lot less trouble to get it done with OpenSCAD. This way your end-result would let you input the size of the bed and it would figure out how many sections it needs, etc.

Lesee… 120x40x40cm is a lot of plastic to print, even with a single printer running all day all night.

What I’d suggest is that you make the wooden outside for the 120x40x40cm shelf and make 20cm x 20cm x 40cm units. At which point you can make bigger multi-part modules. It might actually make sense to keep the cups separate because you could adjust the holes and stuff based on the plant’s needs. Whereas the reservoir section is going to be happiest as a single tub. But the important part is that if you are a few modules short, just add a spacer for this season. And it gives you more time to experiment on the tub and allows you to swap that out mid-season.

This is pretty darn ambitious for a starter project. I say this as someone who is trying to get some fancy new 3D printable tomato cages going before the plants get tall and dangerous and I’ve been doing this for a while.

So you really probably want to de-complicate this, either by only making planters that are sized for the printer or finding a existing planter that’s the right size but not self-watering and designing just the self-watering part. You’ll probably learn a lot about the right way to do one this year and then next year you can attack the next generation of the planters.

The problem with printing in pieces is that you are going to have to make sure that the joints are strong enough for the weight of the soil. This is why using a ready-made outer container might help. In the same way, what you really want is something finger-ish or jigsaw-ish so that the pieces align themselves more easily and interlock.

You will probably want a fatter nozzle, otherwise this is going to take forever to print.

PETG seems to have worked fairly well for me for outdoor stuff? Coating or paint or whatnot is handy. You might want to look at the epoxy family? If you can print on the balcony, you might consider ASA which is totally fine for outdoor use with no paint.

FreeCAD is a bit of a learning curve? The thing that FreeCAD would make easier is a parametric model, where you say that you want a 400 x 400 x 300 planter. Except that if you are really serious about making large self-watering planters that are parametric, you are going to end up wanting to write code to make it all happen, which either means the Python in FreeCAD, the Python in Blender, or maybe just use OpenSCAD.

One avenue, which is also too big of an ask for this season, is making a multi-part model to cast the large pieces in concrete.

Another avenue would be to just design around the outside being wood and the 3D printed parts being brackets and jigs and connectors and the self-watering bits.

My dad designed jet engines and nobody made him design a jet engine on the whiteboard. So you are starting from the right place.

We are here where we are today because we spent too much time thinking that acting like the right kind of nerd meant you were a good programmer. There’s nothing wrong with going to a job, working hard, and then doing something else. I know very productive engineers who don’t have a favorite science fiction book who were great to work with.

Given things lately, I think it’s healthy that a lot of people have had to take a step back and realize that their employer would totally harvest their organs for profit if they could get away with it. Providing people the right “tech subculture” cues has resulted in a lot of people working themselves to death and never seeing any income windfalls.

I actively hate a bunch of my old science fiction books from when I was a kid because they were written with what is, to my adult mind, a not-very-subtle fascist bent. There’s, obviously, some great novels out there that expand your mind … but at the same time, there’s a lot of the science fiction canon where I’d probably hate working with people who took those books seriously.

And, likewise, there’s a lot of people who simply don’t have time because they are smart people actually trying to get into the lucrative field of computer science and a good scifi novel reading session is a luxury they just don’t have.

“Tell me about your favorite science fiction book” is pretty much a textbook case for how to have good intentions but conduct an interview that’s, when you step back and think about it some more, biased. It’s checking for subculture-fit in ways that have nothing to do with how they are at work.

On the other hand, whiteboard tests are also useless.

If you want to make a better interview, I’d suggest you have an interview guide. Not a manager? Just write your own for your interviews and keep to it. This protects you from unconsciously giving the person who looks the part easy questions.

If you want to check for culture fit, talk about things at work that matter. Are you worried someone is going to talk down to a junior engineer? Make them talk about a time they had to mentor a junior engineer. Did they succeed? What did they do? Ask them about the best project manager or doc writer they worked with. Are you worried that they aren’t serious enough about getting shit done at work? Talk about the worst incident they ever were part of, but not the technical parts, just how they made sure it got fixed. Are you worried that they aren’t a good team player? Ask about their best collaborations. Or how they organized work on a large project. Or the time that they took one for the team. If you think through how the last crop of yuppies pissed you off for a while and break it down into questions that they’d not have a good answer to, you should be able to make a nice set of behavioral screening questions and a set of attributes that you want the person to display in their answers.