I haven’t 3D printed anything of my own design in many months, mostly due to a desire to switch from proprietary Onshape CAD to an open source CAD solution. I thought FreeCAD was the obvious thing to learn but after months of struggle I’m starting to think that decision may have been a mistake. While I have a long list of FreeCAD complaints, this page highlights the worst offender in my book: FreeCAD’s error feedback system.

Redundant constraint error has been the biggest enemy to my productivity. The most infuriating aspect is the message “Recompute failed! Please check report view.” It is a general catch-all message promising more details in the report view. The problem is that message is itself displayed in the report view and there are no more details to be found! I thought maybe I need to enable verbose mode or something, so I right-clicked in the report view and activated everything. While that did display more text in the report view, there was nothing I could understand as a helpful direction.

Graphically, redundant constraints are rendered in a different color. But it can be a time-consuming game of hide and seek to find that little icon of a different color within a complex shape. Sometimes I swear I’ve looked at every single constraint and couldn’t find one rendered in a different color.

The toolbar has a “select redundant constraints” icon. In theory I could click on that tool and hit delete to remove the redundant constraints. In practice I click on that tool, hit delete, and get an error message saying nothing is selected.

If the above steps fail, I could click “Undo” to remove the most recent action. Then I have to sit and think about what I did and how it might lead to redundant constraints. I test my hypothesis one by one and sometimes I find a solution that gets me out of my mess.

But then there are the times when I don’t have that option. Recently I drew a profile that I wanted to revolve into a solid. The operation failed with a complaint my profile (wire) is not closed, but it doesn’t tell me where the opening is and I couldn’t find it. The toolbar has a “close shape” icon but, if I click it, my profile is over constrained and I don’t know where to look because I don’t know what “close shape” did. Absent that knowledge I couldn’t form and test hypothesis to repair my shape.

In this specific instance I ended up redrawing the shape from scratch, and it was successful the second time. Experiences like this do not endear me to FreeCAD. Beginners like myself will make mistakes, and we want to learn from our mistakes, but FreeCAD error reporting system is of absolutely zero help. It’s hard for me to be an enthusiastic user when the system wastes my time and saps my motivation by repeatedly telling me to go find a needle in a haystack with no directions.