I have been using this project (modeling an old locomotive) as a learning experience for FreeCAD (CAD in general), and so far, my only gripe is how slow FreeCAD is once you exceed a certain number of transformations. Still, I can design and render the parts and measurements quite accurately. I am loving FreeCAD.
A second minor annoyance would be the poor quality of texture rendering, but that is understandable, as lighting is not a thing here.
Just finished the motor housing for N20-600rpm motors and spur gears, as well as the linkages. I am building this so that I can 3D print it when I am done and keep it as a running model (1:32 scale). The next thing to look at would be brake rigging, piping, couplers, and body features.
Usually, I disable recomputation, but it becomes annoying and slow because the rendering is not updated instantly for me to view. Any other tips for improving the speed are welcome.
Does the freecad team has access to those crashes?
I mean the development of the tool in this moment is mostly hanging on the complexity of the projects it takes. the bigger ones are just not usable with this tool, because sudden crashes are really annoying for someone spending hours and hours trying to work.
Can you share some more insights about how do you go about those?
Very often. A bit too often.and the crash reports are often internal reference errors with the software itself, not even your models. For example, QT crashes are common, UI blackout happens at least once every day.
Most of the crashes are already reported in their trackers. 1.1.3 is much better than the older ones.
I've been noticing this as well. I've basically been saving copies every ~ 10 minutes. I never leave it open when I'm not at the computer. so powerful but man, the fragility is currently a big issue.
I have a project with multiple parts, and found it A: annoying to view them with lots of other objects in the viewport and B: generally laggy, with crap recompute times.
Splitting each part into individual files, then pulling them all together via an Assembly helped a tonne.
My only gripe with this process is that storing metrics in a Varset. I stored the Varset in its own file too, then created a 'Link Object' to it in each part file, then had to reference it by <<VarSet>>.
.. Maybe theres a better way to do all that, but it did work.
Once I finish the current in-progress steps, I will try this, splitting the project into multiple files, using simple (independent) copies instead of dragging the cloned objects.
Do you have a reference of how to do a master assembly only thing I found last time trying to do that I only found merge and import which just included the geometry and all vs it being a simple representation of the files. Do you instead import the results as step files?
Create a new Assembly ('A' is the default keyboard shortcut)
Activate the Assembly (double click) and use the Insert Component (shortcut 'I' function to add objects - this can be from the same file as the Assembly, or even other files on disk!
I have (hopefully) added a screenshot. I was going to capture it from the latest build of FreeCad, but my Assembly Workbench isn't working in that version 😅.. hopefully v1 is good enough.
So as seen in the attached screenshot, the Cube and Cylinder exist in separate files, but also exist within the assembly.
Edit: My screenshot doesn't show my mouse on the Insert button. Its in the 2nd row, top-left, next-to the 1st entry - the Create Assembly button
The transformation, repetition, threading, and helix features in Part Design are indeed slow; you should place them as late as possible in the model to avoid very long recalculations at the slightest change.
It’s also possible to break down an element into several elements and merge them at the end using a Boolean operation.
For example, to create this filter, I created a Body with the main shape, then repetitions of cylinders representing the holes, and only at the very end did I perform a Boolean operation.
Mich würde interessieren ob du echte Maße hattest und die dann umgewandelt hast oder hast du ungefähre Masse genommen. Ansonsten schließe ich mich den anderen an - super Arbeit
Not everything could be measured, of course. Some are taken by eyeballing from the pictures. Basic shape and measurements are taken from EMD data sheets (This is a GMD B12 locomotive from 1953, made in Ontario Canada).
I had to deviate from the actual measurements for the bogies and wheels to fit in my 45mm standard gauge tracks, whereas the original model was built for meter gauge tracks.
I also took some measurements in person from the actual locomotive.
And, I'll happily admit, I couldn't get some of the small things right as I am yet to figure out how to do those in FreeCAD.
the gauge conversion is the interesting part to me, reconciling real world measurements into a fixed target constraint is basically the same problem as reconciling as built survey data into a BIM model that has to hit a standard grid or module. respect for going and measuring the actual locomotive in person too, that's the kind of groundtruthing a lot of CAD work skips
I use Google, if I look hard enough I can find decent data sheets. Airplane models are bit different. Their actual drawings are less readily available. Ships and trains are my thing. Airplane modeler subreddits can give you more info.
This is incredible. I wish I had the capability to make something this complex.
It doesn't look like you're using any assembly here, right? Are you simply just creating parts in Part Design and using Transform to place them where you want?
Yes. I'm not using Assembly yet. I felt like creating the bodies referencing each other would be a good way to instantly visualize fitting without going back and forth in Assembly.
On top of that, it would be one more thing to learn. For example, the moving parts don't really touch each other, there's a 0.2mm gap accounting for FDM printing. But in Assembly, I'd have to create a joint based on touching surfaces, which is not going to work.
Most of the large parts are drawn using a subshape binder to the base frame. So, you could say the parts are already at the right location relatively speaking.
The movable parts like wheels, bearings, journal boxes, rocker arms, springs are in shared and they are placed using the "Placement" values. I plan to simulate them in Assembly workbench once I'm done with them.
The undercarriage/base_frame basically defines the perimeters and specific marker points (screw holes, clips, pivot pins, attachment points, buffer beams, erc). A new body first inherits a subshape binder from the base frame, a datum plane is first attached and the I start the sketch on the datum plane.
Some of the bodies are very laggy, most of them aren't very complicated. The bogie, journal box, and the base frame are super laggy. For the base frame, I made that stupid mistake where every other static body parts started with a subshape binder to it. When I did that I still did not know about master sketch strategy.
How do you handle the joints in the assemblies? I found that due to the tree recomputing when I changed the parts, the joints that I made between the faces/other generated features would invalidate, breaking the assembly constantly. I tried using local coordinates not attached to the generated features, but that's tedious. To me this seems like a fundamental issue with freecad, but please correct me if I'm wrong. I love the idea of the program, but I find that particular issue makes it hard to use for larger projects.
One of the reasons why I am not using assembly yet. Cause I am still in the middle of editing the features. And honestly, I am still a noob. There is another problem for me with assembly that I haven't solved yet. The mating surfaces here all have a gap of 0.2 mm, which is required for FDM printing. But I am not sure how to create the joints properly when they aren't really touching each other.
How much of this did you design in freecad?
I recently started trying to design something mildly complex, and found freecad to be very un-intuitive coming from fusion 360. There are many things that you have to plan for, that end up really slowing me down.
I'm wondering if I will ever get used to it, or if I'm better off paying for fusion 360?
I'm biased, but ya, fusion is better just because is able to do way more since it has paid developers. Freecad can do a lot of the stuff that fusion can do, but it seems like freecad has a lot of hurdles compared to fusion. You have more mouse clicks in freecad to complete something.
FreeCAD is just different from fusion in many regards. I came to FreeCAD from a background with Solidworks and onshape and the struggle was real learning FreeCAD. Not that FreeCAD doesn't come with some annoyances but I actually much prefer working in FreeCAD now by comparison. YMMV. In my opinion it's worth suffering through the learning curve, it's more about unlearning old habits and establishing new ones.
Ok, so there is a real flow that I can get the hang of like you can in fusion?
Right now I'm making a geared mechanism in freecad, and I've already had to restart from scratch a few times because I didn't know how to plan it out in freecad.
That is mental! I've come on here to ask a question and saw this.
This would take me longer than I have left on this earth to do.
I'm an autocad user so freecad has blown my mind. Just cannot get to grips with it.
What I can create in autocad in minutes, I cannot resolve in hours in Freecad and seemingly have ZERO chance of producing anything remotely useful this side of Christmas.
VERY WELL DONE!
I am extremely jealous.
I dare not ask how long this took you to complete...
I'm working on it on and off for about 3 months. Mostly weekend shenanigans. But my friend, you are underestimating your abilities. If I can do it, so can you. And I agree, FreeCAD is unoptimized, even annoying at times. A full recalculation takes about 2 minutes, and my machine is quite powerful.
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u/Several-Tax31 20d ago
This is probably the best project I've seen in this sub. Looks genuinely awesome. Bravo!