FreeCAD - Gorgeous! I am a little intimidated!

[graham-xrf]

I have been using FreeCAD (because it's free)!

I know that one can get into using Fusion360, but I didn't go there because my PC system is not Microsoft Windows. FreeCAD runs on all platforms (Windows, MacOS, Linux). I have been used to using various kinds of CAD for Electromagnetic Simulation, which are not directly for mechanical modeling, but do, of course, have physical metal shapes in their structures. I had a little play with SolidWorks, but I never got to go the whole learning curve with it, because retirement happily intervened.

For my needs, it's only simple models, and I use the TechDraw workbench to print out some dimensioned views to get grubby in the shop. Of course, FreeCAD kept evolving, all down to a genius crowd contributing faster than the main issue could keep up. Every kind of feature they love, if it's not there, they code it and post it. The best of these get incorporated into the main download, so the third-party tools, while they still can work, become obselete.

So now ..


Just how good do you want it to get?
The whole file is freely downloadable from GrabCad.

The step-by-step video is --> HERE

The chap who posts it is from Joko Engineering.
The tricks he gets up to to make sketches become great stuff with simple moves was, for me, a big shift in perspective.
So easy, not many clicks, - and he ends up with a great part
--> HERE

My attempt only needs two countershaft journals (floating about in space) and a correctly located mounting surface to help with the design of a motor adapter bracket. It needs a circular cut-out on a right-angle to mount my replacement motor (ex servomotor with full speed control). I decided to model the drive shaft and wheel, and a pulley of sorts (not seen yet) to help.

My FreeCAD model or the South Bend 9C Underneath drive Countershaft & Drive Wheel.


The real wheel is here (for comparison.


The Joko guy has done another (turbine rotor I think), where he does it side-by-side with SolidWorks, explaining the differences in actions and features.

Clearly now, this free, open source program has gone far beyond the critical point where it takes on a life of it's own. No matter what the field! I can see architecture, mechanical engineering, aeronautical airfoil design, robotics, finite element stress analysis, thermal flow, human body implants, and more..

It has now got beyond us. One person does not have enough life to explore all the FreeCAD stuff out there.
I am thinking that, at the humble level I am going to use it, I am unlikely to need anything else!

 

[markba633csi]

I have started to use it and yes, it is amazing. Don't know if I'll live long enough LOL
-Mark
I generally feel better about investing the time on Linux and Open source stuff in general, the persistent pestering of other OSes and near-constant need to upgrade interrupts the creative flow for me. I've been using the same distro of Linux for over 6 years, very solid.

 

[DavidR8]

Coming from Sketchup these are sure intimidating!

 

[Larry$]

Thanks for the post. I've looked at the program before. Not sure if I can live long enough to learn to use it.

 

[graham-xrf]

I have started to use it and yes, it is amazing. Don't know if I'll live long enough LOL
-Mark

Hee Hee - with me, the "play with it" period" may be a race to keep the ahead of the pestilence!

It takes about 20 minutes to start making sketches, and getting them to become solid bodies.
It takes about 2 hours to get up to speed on the various navigation modes, and selection methods.
If you mess with it for (say) 3 or 4 times, in the first week, you will be working it well, but becoming aware of how much you don't know.

It is important to understand that the "dimensions" seen in sketches are not the sort you have on printed drawings.
Those come about after you have made the model of the body shape, and you move over to the TechDraw workbench (which is awsome)!

The great resource is YouTube, and the website wiki.
For some easy stuff try this -->

Like most of us at HM, unless we are already far into CAD, and have CAD experience, it can get to feel intimidating. Everything this software can do is too much to be fully explored, certainly not by me. But look - If I could manage to make that drive wheel model for the SB9C, then I think most every other HM member can also!

One thing to know. A "body" is a single chunk of something as a joined together shape.
For putting the "bodies" together, you use the Assembly Workbench (another awesome thing).
Exploded diagrams, animations, and all that stuff follow later.
Kinematics, parts clashes, C of G, Radius of gyration, vibrational forces, bending moments, stress, strain, etc.
There are macro tools to call up any standard US or ISO bolt, nut, thread, etc.. It wants for nothing!

 

[samstu]

Thanks Graham. What a valuable bit of information.

Does FreeCAD export STL format. What about CAM? Is this also included or is there also an open source alternative? Do you have a recommendation?

I've been very happy with Fusion360, but given how fast autodesk's stock price is rising, you can be sure they are going to fully monetize that platform.

 

[graham-xrf]

Thanks Graham. What a valuable bit of information.

Does FreeCAD export STL format. What about CAM? Is this also included or is there also an open source alternative? Do you have a recommendation?

I've been very happy with Fusion360, but given how fast autodesk's stock price is rising, you can be sure they are going to fully monetize that platform.

OK - trying to get the info you want..
Re:STL
Yes, it does export STL. Apparently by two methods, with one preferred.
Method 1. You just click on the solid to select it, File -->Export --> and select one of the choices.
Method 2 (Preferred). Use the Mesh Workbench exporter features.

All the formats FreeCAD exports are listed--> HERE
(There are a lot of them!)
The most widely transportable format, that retains all the components (instead of just one big mesh), and is accepted by all software is the STEP format.
Software which is relentlessly proprietary, and chooses to try and lock in it's own format, or changes it with subsequent "versions", then requiring one's drawing archive to be "converted", are shunned by FreeCAD. Sometimes FreeCAD will import, but not export.

Re: CAM
Yes of course. FreeCAD was built for CAM, and 3D printing, CNC G-Code, etc. And yes - the CAM, STL formats, whatever, is always all free. This with a very legally locked up license ensuring that it will stay that way, and measures to make it very risky for any commercial firm to steal the code, or incorporate features, and try for payment.

FreeCAD does have it's own native, open source format also. The unnecessary obfuscation, and deliberate incompatibilities in file formats is what motivated the FreeCAD originators to "roll their own" anyway, and for the early years, it did not have as many features. Now the situation is different. Companies are donating.

We will always have, in the style of the USA, product vendors who can persuade some, usually corporate, users that their software is worthwhile. Free, crowd-sourced products are not very welcome! Maybe they can make the argument, but it has to be about why their product is that much money to pay for the (now small) increment their product allegedly has over FreeCAD, if any at all.

All the CAM, CNC, Robotics, tools - come to that, every single thing about FreeCAD is free, and all the source code is published.
I have not learned much about CAM, but I do know it is widely done.

It uses Python scripting and C++. If there is some tweak you want, you can make it yourself. If a popular feature gets posted, they test it to death, then add it to the distributed version. There are private downloadable AppImage container versions out there that can be run alongside the distro version, featuring the most amazing stuff. I don't have enough life left even to watch all the example videos.

Re: Fusion360.
I once went the route of paying for a "lifetime license" for a PCB/circuits software that had a model where you had to be online to get the engine to run, with some hook in the software that stayed with the vendor. It worked for about a year, and then they announced "changes". I could have played the game longer - but I decided to use the hard copy PDFs, and over time, re-draw the archive into a open source tool. With vendor software, you have to take what you get. With open source, you have the ear of the developers.

 

[DavidR8]

Downloaded FreeCad...let's see if I make better progress than I did with F360...

 

[graham-xrf]

Downloaded FreeCad...let's see if I make better progress than I did with F360...

Go carefully now. From what you said in the past, I think you might be a bit like me when it comes to CAD.
Avoid disappointment by first stepping through some YouTube videos, with the speed set to 0.75 if need be, and learn it a bit.

The various "Toolboxes" are aimed at special tasks, and can get confusing. There will be some initial concepts to learn. There are only two tools to head for as a first move for almost any project. These are the "Part Design" workbench, and the "Part" workbench.

There is lots of example information out there.
A simple example of using the Part workbench is CSG Multi-Body Modeling --> HERE (6:39)
For doing it another way, from Part Design workbench, using sketches, then the previous link --> HERE (25:15)
While it is possible to everything in either, each has it's own (big) advantages. Part Design is the really mighty tool!

First Tips
You move from one to the other toolbench as you may find convenient, but beware creating tangles of disconnected parts within the same body. Also, get into renaming the various parts and sketches almost immediately you create them, using meaningful names, or you can end up hunting through sketches and boolean fusions, revolutions, filleted edges operations, whatever, to find the piece you made before.

If there is another tip I have, it is about seeing the pieces, and hiding them. To make it show, you need to select the body, (one click) and toggle the visibility with space-bar, and then further down the tree, make visible the piece you want with the space-bar. You can then leave that piece on the screen, and move on to other bodies. If they get in the way, switch to wire-frame mode, or alter their transparency, (or just make them go away with the space-bar).

 

[graham-xrf]

A Gear for your Lathe
I forgot to mention, it makes making gears look ridiculously easy!
--> Gears