this post was submitted on 30 Jan 2024
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I thought I would knock some dust off my drafting skills after a small chat with @captain_[email protected]

Seeing this image on the tutorial made me realize, FreeCAD seems to be a Technical Geometry Super-Suite. It makes sense that CAD would grow to include all of these things. But I thought sharing the initial perspective of some one who hasn't looked at this stuff in about 18 years might be interesting.

Granted I'm not actually familiar with most of this stuff, and none of it from the POV of FreeCAD. If this can deliver 10% of what I'm looking at, I'm in for a treat.

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[–] [email protected] 0 points 9 months ago* (last edited 9 months ago) (4 children)

Can it export STL/3MF without making all the circles low poly yet?

Last time I tried it freecad was not usable for 3d printing because it doesn't export properly.

With the naming bug that still exists too I found it basically unusable even for basic parts. It feels like going back 20 years compared to fusion 360.

[–] [email protected] 0 points 9 months ago (1 children)

When I tried it like 7-8 years ago it crashed pretty much every time I touched a constraint. Was I probably doing something very wrong? Yes, but that made it pretty impossible to learn. Opposed to Fusion360 which just yells at you when you do dumb shit.

[–] [email protected] 0 points 9 months ago (1 children)

Sounds like it was only five years behind SolidWorks. The CAD program with one level of Undo, an unreliable Revert option, and active hostility toward incremental saves. It was great for machining because every change was about as permanent and slicing up actual metal.

[–] [email protected] 0 points 9 months ago

The CAD program with one level of Undo, an unreliable Revert option, and active hostility toward incremental saves.

I don't know the first thing about CAD, but lmao.

[–] [email protected] 0 points 9 months ago* (last edited 9 months ago) (1 children)

STL is a total abnormally and a piece of shit of a format that doesn't actually represent 3D objects very well and has a ton of issues when it comes to sharing. Unfortunately we're stuck with this shit format and Autodesk with their Tinkercad seems to want to keep pushing it because as long as we use this crappy format we're forced into sharing and collaborating inside their platform - that at some point might require a subscription.

[–] [email protected] 0 points 9 months ago* (last edited 9 months ago) (1 children)

Completely agree about STL, however, I cannot for the life of me understand why 3MF isn't a binary format.

It has all these big tech companies behind it, and they landed on incredibly short sighted mistake of making the format human readable, instead of providing good tools for reading and modifying the binary format.

Compressing the human readable content is fine for reducing storage size. But de/serializing the XML is going to be at least 3 orders of magnitude slower. Given a sufficiently large file, the difference would be waiting 30 seconds, vs a barely noticeable 0.3 seconds.

[–] [email protected] 0 points 9 months ago (1 children)

What isn’t variant of XML these days? I know, it’s bad but it’s what it is.

[–] [email protected] 0 points 9 months ago* (last edited 9 months ago)

XML isn't as common as one would think. It's been steadily decreasing in popularity and use. It's a very verbose format that is suited to enrich a larger set of data, such as HTML documents. For data heavy documents where, it's a particularly bad match, as you end up using as much text for annotation as the data itself.

Using XML for 3MF is IMHO a technical cop-out, where you don't really want to solve it "correctly", so you go with something that is "good enough". With XML, you know it'll be able to encode anything, be human readable, and have existing parsing libraries in pretty much any programming language and standard libraries. So, it makes sense. However, if you're creating such a format, the least one should do, is write a sibling standard for how to directly binary encode the data. This isn't a hard thing to do. It just need a standard for how to do it, so everyone agrees. Here is an example online on how a rudimentary implementation could be done for OBJ files, but the principle is the same. That way you could chose to export either as 3MF or 3MFB (for binary), and as long as your slicer, and what not, can decode it, you're good.

The hard part of 3MF was all the great work in standardizing what, and how that is represented. The part where it writes that out in clear text, is the only part that is missing. They could probably just pick one of these too: https://en.wikipedia.org/wiki/Binary_XML

[–] [email protected] 0 points 9 months ago (1 children)

I've used it for making models for 3D printing for about 5 years, never seen that issue

[–] [email protected] 0 points 9 months ago (2 children)

Strange, when I looked it up at the time there were a bunch of suggestions for defaults to change and stuff to try and solve it.

You can print circles and not have them come out with flat faces instead of an actual circle?

[–] [email protected] 0 points 9 months ago

So I guess it's only an arc and not a full circle, but I had no problem making this curved sanding block in FreeCAD.

[–] [email protected] 0 points 9 months ago

So I guess it's only an arc and not a full circle, but I had no problem making this curved sanding block in FreeCAD.

[–] [email protected] 0 points 9 months ago (1 children)

I noticed a similar problem importing step files... I no longer had circles, I had nonagons... I would love to delete my windows vm that only exists for fusion 360.

[–] [email protected] 1 points 9 months ago (1 children)

If you are comfortable with all your models being available for download and some wonky Terms of Use that may let random internet people profit off your designs but not you, then OnShape in a full-screen browser feels about as good as F360 does. I guess you could also pay for it, but despite finding it pretty nice, I am iffy about paying Solid Edge prices for something browser based. I understand SolidWorks has slapped together a browser version as well, but nobody likes it.

Linux wise, there's just not much outside FreeCAD and SolveSpace. BricsCAD is an okay evolution of AutoCAD, and VariCAD is a less good one.

I may have done a longer writeup than anybody needed the other day.

[–] [email protected] 0 points 9 months ago

I have tried out onshape and it is a pretty functional fusion replacement, but I really don't like the idea that the models I make can be used (or even just sold) by others commercially. I'd be okay with it if the free version just gave all models made with it an open license that barred commercial use entirely, but banned for me and open for sale by others is pretty dirty imo.