Here’s a list of the most recent FreeCAD tutorials on YouTube, I believe they are not referenced in the FreeCAD wiki.
One thing to keep in mind is that FreeCAD is open source software, developed by a very small team of people in their spare time. The developers cannot spare time to write documentation, they have to rely on the community, which is very small as well, actually a few orders of magnitude smaller than say the Blender community. Which is why there is not much learning material.
So far there’s been only one book published by Packt Publishing. It’s more of an introduction to FreeCAD than an extensive reference book. It looks like it’s not available in print anymore, just in ebook format. http://www.packtpub.com/freecad-solid-modeling-with-python/book
I’ve been thinking of making FreeCAD tutorials but I already spend a lot of time helping newcomers on the FreeCAD forum where my handle is normandc.
Locking down degrees of freedom is done by applying constraints. To use constraints you need to select a sketch object first. When you hover over the icons, a tooltip will appear.
This is the Sketcher constraints toolbar.
I am using the development release of FreeCAD, I know the order of the icons was changed, but I don’t remember if that change was done for the stable release 0.13.1828 or after that.
To the left of the separator are the geometric constraints, to the right the dimensional constraints. You should always prioritize the geometric constraints. For example, rather than dimensioning two lines that share the same length, apply the
equality constraint between them - in case you need to change their size, you’ll only have one dim to change, not two.
You can apply the equality constraint to arcs and circles, this will apply to their radii.
With arcs and circles joined to lines or other arcs and circles, always make sure they are tangent by applying
tangent constraints. If the objects are not joined, select the endpoints of each then apply the tangent constraint: this will join the points together and apply the tangency at the same time.
symmetric constraint is very useful but should be used sparingly in the sketch. The Sketcher is still very young, v0.13 is only the second stable release which includes it. I’ve witnessed that when many symmetric constraints are used in the same sketch, it can lock up elements that are not fully constrained. This is a bug that will need to be addressed by the devs.
The symmetric constraint can for example be used to center a rectangle on the Sketch origin. Simply select two diagonally opposed points on the rectangle, then the origin point, then apply the symmetric constraint.
I recommend centering a rectangle to the origin because this will allow you to use mirrored features later on.
When using dimensional constraints, use the
length constraint sparingly. It should only be used when you need to set an angled dimension. For vertical and horizontal dimensions, use the
vertical distance constraints. This advice comes directly from the developer of the Sketcher internal solver, who told me the length constraint requires more calculation by the solver.
Of course this only covers the surface of the matter. If you want you can supply me a sketch you’ve done and I’ll give you specific advice on it. If you don’t mind hearing a funny French Canadian accent, I’ll even be willing to record a video.
Hope this helps,