Udemy's Blender Course - Learn 3D Modelling

The intro:
My girlfriend wanted to buy me something 3D printing related for my most recent birthday, so I suggested something I wouldn't buy for myself. The class was $12, for 50 hours of instructional videos — bound to learn tricks or better processes unknown to me. I'm not an expert, having learned most of my skills from youtube or practice. (A brief shout-out to SEABUG - a local meetup for Blender. They know a lot of things, share experiences, and really helped expand my knowledge of what was possible. I found them through Meetup, but they also had facebook...just in case you want to look for a local group near you.)

Short answer: please don't spend $12. Wander youtube, check out people like Miguel Zavala (of the D&D monster fame as mz4250), Zacharias Reinhardt...I still really like inventimark's material — as an intro into Blender for 3D printing it's fantastic. You'll progress a lot further in 20 hours there, than 50+ hours in this udemy "class".

What's the key to delivering a good joke?

An hour into the class, and they hadn't even touched the starting cube. The longer I got into the class, the more it felt like they were stretching out content. 50 hours now seemed like a punishment, not a value. [Timing.]

What's the key to delivering a good joke?

3-button mouses. Share your work on udemy. 3-button mouses.  Share your work. Remove doubled vertices. Do an action. Remove those doubled vertices. Do an action. Remove THOSE doubled vertices. Share your work. [Repetition.]

Bad techniques

It's great (and mostly true) there are tons of ways to accomplish the same thing in Blender. It's also true there are BAD ways of doing things. Inefficient, or delivering meshes that don't work correctly. There's nothing stopping you from mass-removal of doubled vertices. (This is in Edit mode, Control-V to get the vertices menu, remove double vertices - only possibly affects selected vertices.)

In a section where they want to low-poly an object, they want to remove an edge loop that is giving definition - alt-select the edge, x to delete the edge loop, alt-select the edge loops above and below that deleted edge loop, then Bridget Edge loops (I use the spacebar to search to get there.) OR...they could have just alt-select the first edge loop, then dissolve edge. See what I mean by inefficient?

Bad knowledge

It's fine if you want to skip a topic that you're not familiar with. It is bad if you want to touch on a subject you know nothing about, and present it as knowledge. In this case, it was about something near and dear to my heart, 3D printing.

That somehow, you need to move your model so the bottom of the base is at 0 on the z-axis. STLs don't have that. Also, setting your scale to 1. Again, you export as an STL, it doesn't know what scale Blender had it at. (If you needed to, as a Blender file imported into Unity — sure. Object>Apply>Scale.)

The statement of "Is the model closed?" Well, the language is "Is the model manifold?" Is there a hole in the mesh that leads to the "inside" of the model...or are there parts within the model, that aren't necessary for printing that should be removed? (Use the 3D Print Toolbox plug-in to check. It isn't great at fixing it with the magic "Make Manifold" button, but sometimes. It can show you the broken bits with the "Check All" button in edit mode.)

Suggestions

They should have broken out non-Blender things as bonus content. How Unity uses your Blender models. Best practices for backing up your work. Their interest in "LEAN" processes.

Instead of talking about that there ARE different ways of doing things, either stick to your techniques (as an expert), or show the different results (or at a minimum the time/effort it took to employ those different methods. I have limited amounts of time, and would like the least amount of brute force needed to accomplish a task...unless the other end result is going to be that much more spectacular.

Get someone to actually edit their slides - it's vs. its? Don't use periods on bullet points (or at the very least, be consistently bad). Always make sure your screencast keys are turned on.

Summary

I skipped reviewing things that were not relevant to 3D modeling for 3D printing. Lighting, camera, animation, the video game related parts...not 100% that I'll finish the "class" at this point. I learned several small bits of information, but not worth the extreme amounts of filler.

The Days of Filament Past and Future

The home models for 3D printing are FDM (fused deposition modeling). The printer has a spool of filament, feeds it into the printer, through a heat sink (so it doesn't melt INSIDE the printer, from the next step), through the hot end to melt it, and pushed through the nozzle by the filament above it being pushed through.

The hot end nozzle on my Mini is .5mm, which is basically its limitation on how thin of a line it can print. Other printers can have smaller ones, with the drawback it's going to take you longer to print a bigger object. This is not the filament size - the Lulzbot Mini uses 3mm, but I've heard you can change the feed rate to be faster in Cura for 1.75mm...but I haven't gone down that road yet.

You can switch nozzles, but be cautious on getting it too tight — it can strip threading on the nozzle and/or the hot end block. Tighten it a bit, try extruding...if you are getting plastic out the sides of the nozzle, tighten slightly more.

ABS
Durable, but toxic fumes. Supposed to be really great at bridging. (Where the filament is essentially strung out over air, between two edges without support material beneath it.) I have been less concerned about strength, and more interested in less toxic fumes...so I basically started with PLA.

PLA
The standard for beginning prints. Easy to print, easy to remove. PLA is non-toxic...except for its dyes. It would be food safe, if not dyed...but the hot-end could introduce toxicity. The other hurdle with "food safe" plastics, is that the printing process leaves the plastic slightly porous - minuscule bacteria could grow within it. Sands fairly well, forgiving as far as temperature...a bit brittle.

HIPS
Very similar to PLA. I think it sands the best. I discovered the problems of printing larger projects with it though....the corners would pull up during the print, layers can separate in such a way that you can't even glue and clamp it. ($30/kg) Snaps easily though.

PETG
So far, this is my favorite filament after several years into printing. It's very durable like ABS, prints easily like PLA. Sanding translucent PETG (like some eSun, $30/kg, prints at 235/85) - it leaves scarring. If you need to clean up a print, consider cutting it with nail clippers. I used to be super happy with Makergeeks PETG - inexpensive, regular diameter (2.85mm experience), and free shipping on top of the constant sales. I just canceled an order that had been sitting around for 3+ months...I kept getting "shipped in 4 days" at every email exchange, or offers of alternative material that also never shipped. Maybe when they get their system back in place again. (Currently a no-buy recommendation as of 2018.10.07.)

Coffee HTPLA v2.0 - Proto-pasta
This is pretty interesting as a concept. It has coffee in the filament, so it smells like a sweet, syrupy coffee as it prints. I received a lovely gift of a half kilogram for Christmas.   You can bake it afterward in the oven on glass/ceramic to give it more durability. It's...tricky to print with.

• It drizzles out even when it is below the print temp of 225.
• It..."feels" sticky.  My hot end looks covered in dark molasses, preventing reliable nozzle-to-disk corner auto-level process. (Want to hear a crunching-like sound? Gah. The hot end keeps pushing down until it gets an electrical connection...and then thinks the board is level at that mistake...this is how you melt a PEI sheet.)
• Upper layers with very little to print will be a dark brown, compared to the ordinary "glossy" shine that an unbaked piece will have.
• Usually have to carefully watch the auto-level (make sure the sticky bits on the tip don't cause problems) AND first layer - the filament doesn't always feed through correctly. I typically have to restart the print 2-3 times. 

Things I haven't tried:

PLA+, PLA-HT - supposedly a better PLA, more durable.

Flexible filament - brands like Ninjaflex. In order for my Mini to print it, I'd need to swap in an entirely new head. ($400 and do-able, but I don't have any ideas that need flexible filament currently.)

Wood+plastic filaments - There are plastic+wood filaments, that can be sanded and (somewhat) stained. I've avoided using it for now - I've read a bit about it gumming up the extruders for users, and I like my printer too much to risk it.

Metal+plastic filaments can actually conduct electricity.