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I keep trying FreeCAD every 3-6 months, but it's so full of little bugs and crashes it's not really usable in my mind. I'm using the version from Debian unstabl

I keep trying FreeCAD every 3-6 months, but it's so full of little bugs and crashes it's not really usable in my mind. I'm using the version from Debian unstable. The UI is unstable (very easy to crash just by fiddling around), and the geometric kernel has a ton of little issues that you have to work around. At every new project I have the liberty of giving it a try without many constraints (no import/export required, minimal assemblies of elementary geometry). I really wonder how can you actually go through the relatively complex projects I've seen as a tutorial, really. I would always give up after a dozen crashes. I've used SolveSpace in at least 4 projects, and I absolutely love it. The UI is different than FreeCAD, but in a very positive way (after learning the basics, I genuinely prefer SolveSpace's a dozen times!). It's a bit sad that SolveSpace's kernel is definitely inferior in terms of capability to FreeCAD (notably: no offsets and no chamfers!), but what is supported _is_ stable. I cannot say the same in FreeCAD, where chamfers would sometimes cause degenerate geometry or downright crash. The only minor complaint in SolveSpace is that currently it's not always obvious to see the construction tree, as it's represented linearly. I bought a copy of VariCAD that I use on linux. But while it's certainly a capable CAD, I really don't like the UI, and the parametric modeling is clunky at best. I don't think there's much more available in terms of parametric modeling on linux if we exclude prohibitive stuff like NX. I'd like to be proved wrong here. I still think the best modeler I've ever used is still Rhino, a joy to work with. But while it supported parametric surfaces, it didn't really allow parametric modeling when I last used it.

delhanty 9y ago
>but it's so full of little bugs and crashes it's not really usable in my mind See my comment below comparing Open CASCADE with Parasolid. Developing B-rep modeling kernels with support for curved surfaces is very labor intensive.
- usernam 9y ago
  I know and cannot deny the enormous effort of OCE. I tried to develop a simpler parametric 2d cad once for almost two years, but couldn't keep up with the complexity before getting myself /something/ I could use. This is why I keep trying. FreeCAD is the closest package we got to a decent CAD in an OSS package, and I cannot wait to avoid using closed software in my designs. But I'm just stating facts here: I couldn't follow the tutorial without incurring in crashes. I similarly tried CadQuery, but incurred with mostly the same issues. But like I said, the issues are also on the UI, not just on the OCE engine. UNDO management is often completely broken. Undoing line properties for instance used to only partially revert line properties, but revert previous geometry changes as a side effect. I got crashes just by toggling snapping states (even before hovering over the geometry that would cause some actual computation to be done). I thought I could help on those issues, but the build process involving OCE is time consuming and requires some non-trivial time investment before you can become an effective contributor (as for most large projects - cannot blame anyone here). I occasionally use FreeCAD also as a simple 2d (non-parametric) CAD package. Still very frustrating. You would think we had more options for 2d drafting, but not really. I do not consider qcad/librecad to be real CAD packages. They're like toys in my eyes. I used inkscape (yes...) with greater results.
  - delhanty 9y ago
    +1 I too would dearly love FreeCAD to succeed because the FOSS world dearly needs at least semi-decent parametric MCAD. My view is that the UI and UNDO problems that you report are likely more tractable than the deeper problems with OCE. My first encounter with CASCADE was before it was Open in 1993 and Maura was still trying to sell it. I was a consultant at the time, and the client at the time was initially sold on it by the Matra salesman. At the end, though when CASCADE utterly failed to perform he had a screaming row with the Maura consultant. CASCADE was refactored from Euclid which was the loser MCAD system of the time because it didn't really support curved surfaces properly. Then Dassault purchased Matra, presumably for the Euclid client base who they swiftly moved onto CATIA, and they saw no value in the CASCADE technology so OCE was born.
gh02t 9y ago
I've used Solvespace a lot and agree, it's very intuitive and stable. Unfortunately it lacks a lot of the more in-depth features and also its constraints engine gets confused very easily, plus it doesn't do great with curved surfaces. I ended up moving away from it after getting frustrated that certain tasks were oddly difficult and complex, e.g. fillets/chamfer or changing the color of an object. Nowadays I mostly use OnShape. It's similar to Solvespace in terms of workflow, but more comparable to a "real" CAD package feature-wise. It's also free for hobby use as long as you are willing to share your designs. The major disadvantage (to me at least) is that it isn't OSS, but by virtue of being in-browser it at least runs on Linux. Edit: I'd also still recommend Solvespace, especially if you just want to do some basic drawings or learn parametric CAD.
- delhanty 9y ago
  Is Solvespace history based parametric CAD? FreeCAD's architecture that combines history based modeling with inferior kernel (Open CASCADE) is about the worst choice from a reliability standpoint. The best kernel, Parasolid, only started to get good when mainstream Unigraphics went history based parametric in 1992. The reason is that all of sudden Parasolid has to be able to correctly rebuild every model ever made in Unigraphics, SolidEdge and SOLIDWORKS - including bug-for-bug compatibility. That's an extremely hostile evolutionary environment, and to survive Parasolid had to get extremely good. OpenCASCADE in contrast only has to replay FreeCAD models, and there are modulo zero of those, and actually zero paying customers. SpaceClaim has things the right way round to built a reliable CAD system: direct modeling X still v good b-rep kernel (ACIS). Free/open source doesn't have a good curved surface kernel. To build one is difficult. Every time you add a new surface or curve type, then case analysis for the intersection algorithms goes up with the square, so the key is to limit severely the number of surface types. One though I had was to just use Dupin cyclides (which covers the quadrics) and approximate everything else with cyclide sheets. There are some architectural CAD papers on these. Disclaimer: Parasolid dev 1989-1995. Edit: maybe that's what Solvespace does - limit to just NURB surfaces? Way to go! The Dupin cyclide approach would have to approximate NURBS with cyclide sheets, but the intersection algorithms could be easier to implement because they are implicit quartic surfaces.
kanzure 9y ago
> and the geometric kernel has a ton of little issues that you have to work around Under the hood, OpenCASCADE is an eyesore. Here are my notes from a deep dive where I was attempting a sane reimplementation: http://diyhpl.us/wiki/cad/opencascade/ http://diyhpl.us/wiki/cad/opencascade/
- phkahler 9y ago
  The was talk of using OpenCASCADE in solvespace, but it has not happened. If it's the source of crashes in FreeCAD then maybe that's not a good idea.
xrange 9y ago
>...it's so full of little bugs and crashes it's not really usable in my mind. I'm using the version from Debian unstable. Ever try it on another platform or build? I've been learning FreeCAD for the past few months, and while have certainly come across "quirks" (like certain boolean operations not working quite right, the polar array feature in the Draft workbench working with everything I throw at it, but the polar array feature on the Part Design workbench choking on somethings, etc.). I've never had it crash. I've been using the "stock" v0.16 x64 build on Windows 10. It could be that since I'm just a CAD newbie, that I'm not exercising it hard.

delhanty 9y ago

>but it's so full of little bugs and crashes it's not really usable in my mind See my comment below comparing Open CASCADE with Parasolid. Developing B-rep modeling kernels with support for curved surfaces is very labor intensive.

usernam 9y ago
I know and cannot deny the enormous effort of OCE. I tried to develop a simpler parametric 2d cad once for almost two years, but couldn't keep up with the complexity before getting myself /something/ I could use. This is why I keep trying. FreeCAD is the closest package we got to a decent CAD in an OSS package, and I cannot wait to avoid using closed software in my designs. But I'm just stating facts here: I couldn't follow the tutorial without incurring in crashes. I similarly tried CadQuery, but incurred with mostly the same issues. But like I said, the issues are also on the UI, not just on the OCE engine. UNDO management is often completely broken. Undoing line properties for instance used to only partially revert line properties, but revert previous geometry changes as a side effect. I got crashes just by toggling snapping states (even before hovering over the geometry that would cause some actual computation to be done). I thought I could help on those issues, but the build process involving OCE is time consuming and requires some non-trivial time investment before you can become an effective contributor (as for most large projects - cannot blame anyone here). I occasionally use FreeCAD also as a simple 2d (non-parametric) CAD package. Still very frustrating. You would think we had more options for 2d drafting, but not really. I do not consider qcad/librecad to be real CAD packages. They're like toys in my eyes. I used inkscape (yes...) with greater results.
- delhanty 9y ago
  +1 I too would dearly love FreeCAD to succeed because the FOSS world dearly needs at least semi-decent parametric MCAD. My view is that the UI and UNDO problems that you report are likely more tractable than the deeper problems with OCE. My first encounter with CASCADE was before it was Open in 1993 and Maura was still trying to sell it. I was a consultant at the time, and the client at the time was initially sold on it by the Matra salesman. At the end, though when CASCADE utterly failed to perform he had a screaming row with the Maura consultant. CASCADE was refactored from Euclid which was the loser MCAD system of the time because it didn't really support curved surfaces properly. Then Dassault purchased Matra, presumably for the Euclid client base who they swiftly moved onto CATIA, and they saw no value in the CASCADE technology so OCE was born.

gh02t 9y ago

I've used Solvespace a lot and agree, it's very intuitive and stable. Unfortunately it lacks a lot of the more in-depth features and also its constraints engine gets confused very easily, plus it doesn't do great with curved surfaces. I ended up moving away from it after getting frustrated that certain tasks were oddly difficult and complex, e.g. fillets/chamfer or changing the color of an object. Nowadays I mostly use OnShape. It's similar to Solvespace in terms of workflow, but more comparable to a "real" CAD package feature-wise. It's also free for hobby use as long as you are willing to share your designs. The major disadvantage (to me at least) is that it isn't OSS, but by virtue of being in-browser it at least runs on Linux. Edit: I'd also still recommend Solvespace, especially if you just want to do some basic drawings or learn parametric CAD.

delhanty 9y ago
Is Solvespace history based parametric CAD? FreeCAD's architecture that combines history based modeling with inferior kernel (Open CASCADE) is about the worst choice from a reliability standpoint. The best kernel, Parasolid, only started to get good when mainstream Unigraphics went history based parametric in 1992. The reason is that all of sudden Parasolid has to be able to correctly rebuild every model ever made in Unigraphics, SolidEdge and SOLIDWORKS - including bug-for-bug compatibility. That's an extremely hostile evolutionary environment, and to survive Parasolid had to get extremely good. OpenCASCADE in contrast only has to replay FreeCAD models, and there are modulo zero of those, and actually zero paying customers. SpaceClaim has things the right way round to built a reliable CAD system: direct modeling X still v good b-rep kernel (ACIS). Free/open source doesn't have a good curved surface kernel. To build one is difficult. Every time you add a new surface or curve type, then case analysis for the intersection algorithms goes up with the square, so the key is to limit severely the number of surface types. One though I had was to just use Dupin cyclides (which covers the quadrics) and approximate everything else with cyclide sheets. There are some architectural CAD papers on these. Disclaimer: Parasolid dev 1989-1995. Edit: maybe that's what Solvespace does - limit to just NURB surfaces? Way to go! The Dupin cyclide approach would have to approximate NURBS with cyclide sheets, but the intersection algorithms could be easier to implement because they are implicit quartic surfaces.

kanzure 9y ago

> and the geometric kernel has a ton of little issues that you have to work around Under the hood, OpenCASCADE is an eyesore. Here are my notes from a deep dive where I was attempting a sane reimplementation: http://diyhpl.us/wiki/cad/opencascade/ http://diyhpl.us/wiki/cad/opencascade/

phkahler 9y ago
The was talk of using OpenCASCADE in solvespace, but it has not happened. If it's the source of crashes in FreeCAD then maybe that's not a good idea.

xrange 9y ago

>...it's so full of little bugs and crashes it's not really usable in my mind. I'm using the version from Debian unstable. Ever try it on another platform or build? I've been learning FreeCAD for the past few months, and while have certainly come across "quirks" (like certain boolean operations not working quite right, the polar array feature in the Draft workbench working with everything I throw at it, but the polar array feature on the Part Design workbench choking on somethings, etc.). I've never had it crash. I've been using the "stock" v0.16 x64 build on Windows 10. It could be that since I'm just a CAD newbie, that I'm not exercising it hard.