It must be so hard to lose a child. I hope I die beforre my children.
@Geit, and anyone else interested. I would like to revise the challenge. It appears that filleting is the major stumbling block to getting a finished product like this:
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In F360 it was quite simple. In openSCAD it would have been reasonably complicated to implement, and required long compute times. In FCAD I have been able to replicate parts of it, but not the totality. I’ve tried additive & subtractive techniques. I haven’t been successful with either. As I said in my original post, I’m sure that’s mostly my lack of knowledge & skills with FCAD. In a YT video, I watched Joko Engineeringhelp create an engine manifold using a bunch of techniques I haven’t really been able to follow, but he seemed to use a subtractive process. It was inspiring & daunting to watch.
So, my revised challenge is to create the headrest hanger with all the filleting of the model in the photo. Here are the dimensions:
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When a dimension says r=?+, the + means that radius, or greater.
I thought a filet was something you got from a fish. That’s how equipped I am for this challenge and unless it can be done in Tinkercad I’m not ready yet.
You do get a filet from a fish; not to be confused with fillet, which is something done to 3D shapes in woodworking, metal working, stone masonry, etc.
I looked into Onshape and how the feature works there. It could indeed be added to the existing part workbench as MultiPad or MultiPocket function in a workflow compatible way, where you select the elements from sketch first. This could be done by simpy cloning the selected shapes into an pad/pocket entry.
However at the current state and with the broken reference stuff this would just be another feature breaking apart, when changing the original sketch so maybe it will come sooner than we expect. Implemented like shown above I can see an advantage over cloning a sketch by hand doing it, right now.
In addition to that the visualization of sketches should be improved a lot in FreeCAD. I see Onshape and Fusion do a better job. In FreeCAD you open a sketch and nothing is visible until you “make it fit” when depending on your scale the measurements are all over the place. This is sometimes very annoying.
I’ve never used Onshape so I just looked it up. I see they have an open source version, but it’s completely cloud based and your projects are all completely public. I guess this is how they prevent license abuse, by making sure you can’t create private designs. It’s an interesting approach, and I’m sure it’s something Autodesk has considered. I do not like the fully cloud based aspect. I prefer to have the ability to work offline when I like.
From your description, it seems as though FCAD has a fundamental flaw in its core engine. I liken it to having a logic error in ring 0 of an operating system. To me, this has to be addressed. Having references to parts of a model change during development of the model is, to me, an ultimately fatal flaw. For sure, the engine doesn’t follow functional programming concepts.
BTW, I’ve used a number of approaches to creating the headrest hanger. They all ran into 1 issue or another. For my latest test, I decided to create multiple bodies and then fuse or cut them together using the Boolean tool. This has gone much better, overall, but it still has it’s issues, one of them being that it creates a complicated Combo View tree. However, the filleting is much better because I do most of it on the separate bodies, and only do the joints the bodies have in common after fusing/cutting.
The process of fusing/cutting is awkward and tedious. My main issue is I don’t really understand how to get a sketch from 1 body to another so its geometry can be imported into a sketch in the new body. I’ve gotten it to work sometimes but not other times. In all cases, the sketch seems to carry over references from its previous body, which I don’t want. I just want it for reference in the new sketch. I finally resorted to noting down the measurements and recreating the sketch from scratch in each body. Talk about redundant!
I also realised something yesterday. If I was to create each body part in FCAD, export each part to STL, then bring all the parts into Cura, I could move the parts on the Cura build plate and join them together there. Of course, I would lose the inverse fillets at the points where the parts join, but it would work otherwise.
Overall, it is 100 times easier to do in F360. FCAD seems to be missing a few key features that would make it a world class competitor to F360. Let’s see what v0.2 (or whatever they decide to name it) offers.
Learning FreeCAD and taking up the challenge. This has most of the features, but isn’t all the way there yet with the fillets:
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This was all done with the Part Workbench ala Ganson using a tube, wedge, and cube along with some shapes for cutting also done in the Part Workbench. Fillets also done in the Part Workbench, but wasn’t able to get all the fillets made. It is parametric with all the dimensions defined in a worksheet.
I might try again later as I learn more about FreeCAD.
seat hook challenge.FCStd.zip (56.7 KB)
Not bad, not bad at all. As you noted, fillets are an issue with FCAD. I see the bottom edges have no filleting, along with top & bottom edges of the finger slot, and the inside edges of the feet. Not sure if this was a choice or limitation of FCAD, but the feet are supposed to have a lot more filleting.
1 question: how long did it take to create?
Making the body and doing the cutting using spreadsheet parameters all went very smoothly–probably about 1 to 2 hours. The wedge tool in the Part workbench was new to me, so I was figuring that out. I spent more time fumbling around with the fillets and never could get them all working. Experienced a lot of errors and crashes when it came time to try to fillet.
I uploaded the wrong FreeCAD file last night. The one I meant to upload is attached here.
seat hook challenge C.FCStd.zip (137 KB)
Yes, fillets are an issue, it seems, in quite a few CAD programs. OpenSCAD doesn’t do them well. FCAD does them better than openSCAD, but it has many limitations. @Geit says it because the rendering engine in FCAD doesn’t keep its reference numbers for the parts of a design constant. IOW, each time it renders it reassigns different numbers to parts of the design, making it difficult or impossible for FCAD to keep track of dependencies. Not surprisingly, filleting involves a lot of dependencies.
I’ve heard rumors that the FCAD developers are working on changing this behavior, which I think is a great idea. If I’ve gotten any of this wrong, I defer to @Geit: AFAIC, he’s the resident expert on FCAD.
I love that you folks are doing challenges together. This is very exciting. Thanks for participating in building the community.
I just wish I had more time to participate. I retired from the corporate world about 2 years ago and I am busier now than I was when I was “working” full time. So much to learn, so much to teach, so little time.
Welcome to the world of retirement Irv. I worked well past when I could have retired. That was a mistake. I retired a decade ago. Retirement is much better than working IMHO. And, yes, for some reason, life gets busier in retirement: never enough time to get everything done. It’s a paradox.
I am the laziest retiree that I know. A lightning bolt retired me more than I could have ever guessed.
And yet, look at home much time you spend here and doing 3D printing… I rest my case 
I need to challenge my brain dead problems. So many things I used to do I can’t do any more. I’m down to crossword puzzles and 3d printing.
Nicely done. As the creator of this design, I’m impressed with your efforts. And yeah, the topological naming issue is a huge PITA, which is why, at least for now, I’m sticking with F360. This is mainly because, for several decades, and as part of my scientific training, I take an iterative approach to most things. Not being able to go back & forth & get reliable, repeatable results is just too frustrating.
Great job, Zardozer! You got many more of the fillets to work than I did.
Is there a tutorial/course that you have been using to learn FreeCAD? I’ve been going through the Mark Ganson YouTube playlist. His videos are far from polished, but I keep learning enough from them that they are worthwhile to me.
Thanks guys. Yeah, I’ve been at it for a couple of weeks now looking at tutorials on Youtube, but I don’t think I’ve seen any that you guys aren’t seeing.
I think Mark Ganson’s are pretty good for a lot of basic stuff, and it was really good that he introduced the spreadsheet practices right off the bat. But he was using the Part workbench for most of the beginning, and I’m liking the Part Design wb more. Inventbox Tutorials has also a good series… I’ve gone through several of those. The other ones I’ve followed are the Joko videos, but he has them all over the place and I have to do a fair amount of rewinding on those. They’ve been really good to get an idea of how a professional might tackle a design, and I did a few like the wheel through trying to memorize the method and then do my own sketching and dimensions so I didn’t have to follow exactly along. Finally, a guy named Brodie Fairhall has some very good new videos too, pretty well-polished. Hopefully he sticks around and makes more.
If anyone has any good methods for working around the topological naming issue as it relates to fillets/chamfers, I’d love to know! I did give the dev version where this issue is supposedly fixed a spin, but I didn’t really want to use something so bleeding edge and have file compatibility problems with a lot of users (I don’t even know if there would be problems, just guessing).
Do you have a link to the dev version that supposedly fixes the TN problem?
The realthunder release is here:Releases · realthunder/FreeCAD_assembly3 · GitHub
I think he’s one of the main devs of FreeCAD, and the work on this is supposed to go into the next version.