3DPrinting

It's not great for every use case, but my 'get this printable' solution is Tinkercad. It's pretty easy to use, but is correspondingly simple.

Netfabb before Autodesk fucked it will fix a lot of hanging vectors, Sketchup is just way easier to use than any CAD software I've every used but may or may not be able to open files included with Thingiverse downloads, depending on what was used to make them.

DM me if you need a copy of either. I've installed both on Linux in the past as well and have a link to some documentation on that.

I find that being able to sketch up things I need in CAD and then print them is both cool and really useful. It's the main reason I bought a printer in the first place. Thus far I've tried out FreeCAD, Solid Edge, and Blender. With any modeling package, you will have to dedicate time on a regular basis to really get used to them. FreeCAD is certainly nice for the fact it's free, just as it implies. I used it to design a few parts that were functional. It works, has some useful workbenches and add-ons. My problems were the software having bugs that caused models to break when trying to make changes, and available training info was often outdated. Siemens offers a free version of Solid Edge to makers, which is really nice, even with some of the advanced features turned off. It's a much more polished program with great training resources. You can only export designs as stl files, but that's fine for 3d printing. Solid Edge will slice and print, but I always import files into Orca and go from there. Blender looks really amazing for modeling, but I admit I haven't spent enough time learning it yet. You can use it to manipulate meshes, which is useful for customizing and fixing models. I've used it to Frankenstein together different models for custom prints I wanted. But yeah, while you don't have to learn to use modeling software to do prints, it opens up so many options for you to be creative. I think it's worth while.

Google's sketchup (last free version is from 2017, but can still be found) is easy tool and still has bunch of mantained add-on's.

Even though I have FreeCAD installed (and I thinkered in it) I use SketchUp for all my prints.
Plus in comparison to FreeCAD SketchUp has no learning curve (plus I learned some tricks from free tutorial videos Trimble uploads)

I was in a simiar boat, but once I started learning it really took off and I couldn't find enough things to model/fix! I started with meshmixer, it's pretty simplified but still somewhat powerful and I think Windows only. Once I found stuff I couldn't do with it I switched to blender and now I'm much faster with it. I found there are some things each implements better so if having an issue I'll switch and try something else. I highly recommend picking one and watching youtube videos specific to what you want to change in a model

Edit: you may be able to get by on some of the connectors by lowering flow too, depends on how dialed in your printer is, everyone needs different tolerances

i've been dying to try an llm that can generate stls from natural speech

In my view CAD is always worth learning, especially if you understand what prints best on your printer.

FreeCAD is basically the worse possible beginners tools. Don't get me wrong when you learn it, it's good and comparable to professional CAD software. But the learning curve is dumb.

Learn the basics first. TinkerCAD is free (from Autodesk) and will get you started. But if you want something which would take you further Fusion360 is fantastic for beginners.

The workflow of CAD is as follows. Sketch -> Action -> Sketch -> Action. Lets say you want to make a box with a hole in it. Sketch the outer box -> Extrude it -> Sketch the inner box -> Extrude/Cut it.

I was recently roughly in the same place. I have played around in the past with a few things, but there were reasons I didn't really get into any of them: Fusion360 and their increasingly limited free options, OnShape and their online only thing... so on...

FreeCad has a new release candidate for what they're calling version 1.0, meaning they consider it a mature and functional piece of software. I've been working with it, and yeah... it's not perfect, but it's definitely usable now. I figured if I was going to put all that effort into learning something, I might as well learn something that would always be free.

Get SketchUp Make 2017 from the wayback machine. Is super intuitive and you can import stl files directly.

Most of the CAD software mentioned here will not be super helpful in modifying meshes (like STLs), but they're great if you want to redesign the part from scratch :)

Tinkercad is the exception, as it works with meshes and booleans.

I've been reading the other comments, and while people are encouraging, their comments seem a bit too "you HAVE to learn CAD." You definitely don't NEED to know CAD. I made basic parts and modifications in the slicer for nearly a year after I started printing, and it worked really well. However, if you are considering learning a full CAD program, I have two pieces of advice.

First pertains to if you are working with functional parts. Then you are talking about a parametric CAD program (fusion, onshape, FreeCAD, etc.). In this case, I think it's worth learning for you, and it's not as hard as it seems. You say you have SketchUp experience, so I'm assuming you have decent spatial reasoning. I know someone with no tech literacy nor programming experience who learned a CAD program very well in less than a month of following tutorials in her free time. Just give it a try, and it's a skill you'll be happy to have.

If you are working with cosmetic parts like miniatures and helmets, then you might need to use something like Blender. Admittedly, that can be even more challenging than the other CAD programs I mentioned. However, if you spend a few hours learning some basics from YouTube, you should be able to do fundemental things like fixing holes.

Hope this helps. Good luck with your printing endeavors!

@Krauerking my opinion is no. For many things you can find a model on line. Much of the challenge can be getting the printer to work as you wish, so modelling might not be first on the to do list.

Yes. Advise against doing what I did which is getting weirdly agile with modeling in the slicer at the cost of making cad software less desirable to learn. I finder Tinker cad pretty limiting and personally I can do more in slicer than I can with tinkercad. I do like Mattercontrol which is free, easier to use, and more powerful than tinkercad.

If you happen to have any background with coding, I recommend OpenSCAD. There are a (relatively) limited set of instructions, easy to pick up if you do any other coding.