hit wall trying to learn freecad

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Adouglas
Posts: 7
Joined: Wed Aug 31, 2016 9:37 pm

hit wall trying to learn freecad

Postby Adouglas » Mon Sep 02, 2019 4:04 pm

I have gone through Yorik's tutorial, and read around a lot on the wiki, watched quite a few videos and spent tens of hours trying to fuddle with freecad.

I think what I need is to see a video or in person of someone actually using it to do serious, real things. Anyone know where I might find this?

The issue I keep encountering is fundamental unuseability, like with the table example in Yorik's manual, the way the table is made is totally impractical for more complex systems. A goal I have is to design something like this, which I did in fusion:
https://a360.co/2PAS2Am
I mean design, not just draft it. That entails doing things in a way that you can change things as you go to some degree, although it is never trivial to do so in cad of course.

I have used onshape, solidworks and fusion to some degree each, though I am a long way from being an expert. Do you think you can practically even do this stuff in freecad?
I want to apply it most of all to open source ecology, I don't know if you have heard of it.
freecc
Posts: 158
Joined: Wed Feb 21, 2018 4:17 pm

Re: hit wall trying to learn freecad

Postby freecc » Mon Sep 02, 2019 6:31 pm

Adouglas wrote:
Mon Sep 02, 2019 4:04 pm
I have gone through Yorik's tutorial, and read around a lot on the wiki, watched quite a few videos and spent tens of hours trying to fuddle with freecad.

I think what I need is to see a video or in person of someone actually using it to do serious, real things. Anyone know where I might find this?

The issue I keep encountering is fundamental unuseability, like with the table example in Yorik's manual, the way the table is made is totally impractical for more complex systems. A goal I have is to design something like this, which I did in fusion:
https://a360.co/2PAS2Am
I mean design, not just draft it. That entails doing things in a way that you can change things as you go to some degree, although it is never trivial to do so in cad of course.

I have used onshape, solidworks and fusion to some degree each, though I am a long way from being an expert. Do you think you can practically even do this stuff in freecad?
I want to apply it most of all to open source ecology, I don't know if you have heard of it.
I'm not volunteering to be your teacher, but that is very much doable with freecad. Sketches, extrude, boolean operations, sweeps will solve most of it.
RatonLaveur
Posts: 348
Joined: Wed Mar 27, 2019 10:45 am

Re: hit wall trying to learn freecad

Postby RatonLaveur » Mon Sep 02, 2019 8:17 pm

What version are you using?

Yesterday a colleague of mine who's heard me yap about freecad for months now said "yeah I've had it on my computer forever but everything is too complicated and you can't build much that is useful on it."
I deleted his 0.16 version. Installed the release 0.18, simplified the number of accessible workbenches and a few other parameters of convenience. Then i downloaded work-feature and manipulator. After this, once i taught him about datums and shapebinders (mind you he had not used cad in a while and isn't an expert, neither am I) he was on his way.
chrisb
Posts: 19484
Joined: Tue Mar 17, 2015 9:14 am

Re: hit wall trying to learn freecad

Postby chrisb » Mon Sep 02, 2019 9:24 pm

Such models are very well possible. The red cylinder seems to be some sort of revolve, most other stuff looks like using mainly pads and pockets.

There is the Users Showcase forum with great models. ppemawm has given some explanations on how he has built his models.
Adouglas
Posts: 7
Joined: Wed Aug 31, 2016 9:37 pm

Re: hit wall trying to learn freecad

Postby Adouglas » Mon Sep 02, 2019 11:24 pm

I know about datums, although I don't see much what they have to offer much here, I have never heard of shapebinders... it still remains a mystery to me exactly how you would model such a thing, especially in a reasonably efficient way.

for example, with the table yorik uses in his tutuorial https://legacy.gitbook.com/book/yorikva ... al/details in a workflow similar to fusion I would make one of the legs to spec, by sketching the cross section of the leg, extruding it, then making sketches for the holes and using the cut tool, then make the table top, then simply copy and place the remaining legs into position on the table. Or maybe place the reference plane knowing what size I wanted the table to be, then mirror the leg once to produce an extra leg, then mirror both those at once to produce the other two legs, and draw the table top in a a way that references the positions of the legs. boom, quite fast to do.

This thing with making rectangular prisms (they are not cubes...) and subtracting them from each other by tediously calculating the correct positions is not practical for more complex things. It may work by a hair's breadth when you are just drafting i.e. creating a 3d solid from 2d drawings that already have all your dimensions. But to actually design like that is.... not practical at all, because it is too impractical to change anything or test etc. I also noticed that the holes are not in sensible locations in yorik's stuff. Similarly, the lego bock when made according to his instructions would not actually work, the features on the bottom part don't actually line up with the pegs on the top. if you tried to 3d print out the brick and stack them like real lego they would not fit together at all. The features are not positioned in the right places.


I don't suppose these guys that managed to get along ok made any videos showing exactly how? I think that is the only way to clarify this mystery...
vocx
Posts: 1848
Joined: Thu Oct 18, 2018 9:18 pm

Re: hit wall trying to learn freecad

Postby vocx » Tue Sep 03, 2019 12:34 am

Adouglas wrote:
Mon Sep 02, 2019 11:24 pm
...
This thing with making rectangular prisms (they are not cubes...) and subtracting them from each other by tediously calculating the correct positions is not practical for more complex things. ...
This is the way 3D models have been created for many years. It's what is called Constructive solid geometry workflow. It's a slow and somewhat tedious way of working, which is why it's no longer used by most people. This is basically what the Part Workbench was created for. It provides basic shapes and boolean operations so you can create any other solid object. It's tedious, but it works.

What nowadays people use is called feature editing workflow, in which you use a base sketch, and then an operation like a Pad to give it thickness; then you can add more "features" that are automatically added to or subtracted from your initial body. The PartDesign Workbench is meant to use this workflow, as do many modern commercial systems like Catia, SolidWorks, SolidEdge, etc.
I don't suppose these guys that managed to get along ok made any videos showing exactly how? I think that is the only way to clarify this mystery...
Since you don't have a lot of experience using CAD, it's natural that you find this difficult. You just need to practice more. That's why there are many written tutorials (Tutorials#Modeling_Parts) and Video tutorials available.

You should seek information meant for FreeCAD 0.17 and above, as tutorials made for 0.16 and below may confuse you, as there were important changes in PartDesing Workbench between 0.16 and 0.17.
RatonLaveur
Posts: 348
Joined: Wed Mar 27, 2019 10:45 am

Re: hit wall trying to learn freecad

Postby RatonLaveur » Tue Sep 03, 2019 7:22 am

The whole assembly can seem overwhelming, but none of these parts individually seem difficult to design.

If you're to introduce yourself to FreeCAD, I'd start with the simplest elements, and then build from there.

https://www.freecadweb.org/wiki/Feature ... ble_models

This ressource is really good too.
openBrain
Posts: 2342
Joined: Fri Nov 09, 2018 5:38 pm

Re: hit wall trying to learn freecad

Postby openBrain » Tue Sep 03, 2019 10:33 am

When looking at last Joko realization, I can only think that the object in the OP is definitely doable with FreeCAD. :)
freedman
Posts: 1023
Joined: Thu Mar 22, 2018 3:02 am
Location: Washington State, USA

Re: hit wall trying to learn freecad

Postby freedman » Tue Sep 03, 2019 5:39 pm

Using CAD is where the rubber hits the road. You can imagine stuff all day but having to actually form it and assemble something. For a new project I draw on just about everything, new mail is one of my favorites, postits, garage wall, I have lots of grid pads.

Typically once we find a tool and start using it we are almost instantly more productive. CAD software is almost the opposite, initially it sucks a bunch of time from your life but once you get the hang of it you get more productive.
Adouglas
Posts: 7
Joined: Wed Aug 31, 2016 9:37 pm

Re: hit wall trying to learn freecad

Postby Adouglas » Wed Sep 04, 2019 10:04 pm

hm, I need video of someone actually using the system, tutorials I have surpassed now.

As an aside, and just an aside, I noticed that some of the models are not ready to make. Not actually precise. The model I showed in the op was/is ready to manufacture, fully precise. That's the way I try to work.