Sketcher: B-Spline pages

[jnxd]

If the B-spline page should contain a section explaining knot vector. This would pump up the page.
But OK, let's add this.

However, please don't change the existing didactic order of the Wiki page that we can rely on the video lecture we link.

OK I'll keep the videos in mind when I write about knots.

We should also consider referring people to more robust literature for more involved stuff. ...but I don't think it belongs in the wiki.

Yes, but all this please in the separate Wiki page.

Oh I just meant let's write less in the more math oriented pages, and instead cite other sources.

[uwestoehr]

Oh I just meant let's write less in the more math oriented pages, and instead cite other sources.

OK. Let's discuss this further once you added the knots section.

[abdullah]

Bonus if they can convert it to C++ code

Sagemath (now Jupyter notebook) has a c code generator. I used it for error and gradient functions in solver's ellipse. While this worked, it leads to very difficult to follow code. Some of them were later changed to use DeriVector (great DeepSOIC's class). This was way better readable.

...

The solver does not know about BSplines. It only sees circles (the current master). BSplines are there only because the solver can manage circles very well, and OCC can paint B-Splines based on poles. My lack of good understanding of B-Splines (and lack of time to gain a good one) is one of the reasons why I have been unable to improve B-Spline support. This is also why I am know interested in this work. Sorry.

[jnxd]

Sagemath (now Jupyter notebook) has a c code generator. I used it for error and gradient functions in solver's ellipse. While this worked, it leads to very difficult to follow code. Some of them were later changed to use DeriVector (great DeepSOIC's class). This was way better readable.

I see. Guess it's worth taking a look at Jupyter.

The solver does not know about BSplines. It only sees circles (the current master). BSplines are there only because the solver can manage circles very well, and OCC can paint B-Splines based on poles. My lack of good understanding of B-Splines (and lack of time to gain a good one) is one of the reasons why I have been unable to improve B-Spline support. This is also why I am know interested in this work. Sorry.

Not sure to what extent the solver now "knows" about B-splines with the new code. Because of the nature of B-splines they have to be handled differently. Let's touch base when you're done with the current PRs (in the appropriate forum)

[jnxd]

Oh I just meant let's write less in the more math oriented pages, and instead cite other sources.

OK. Let's discuss this further once you added the knots section.

Written something about knots.

[uwestoehr]

Written something about knots.

Thanks!

I modified https://wiki.freecadweb.org/B-Splines#Knot_vector now to
- link the videos
- to be consistent with the above and below sections (I also adapted the "non-uniform" section below)
- to make clear that "n" is the degree

[uwestoehr]

I modified https://wiki.freecadweb.org/B-Splines#Knot_vector now to
...

I also
* omit the mention of the DeBoor algorithm and the mathematical details. As spoken, this can go to a dedicated math page.
* adapted the wording to be consistent with https://wiki.freecadweb.org/Sketcher_BS ... escription