I want to grid the mesh circle like the image in geometry nodes.
This is maybe a bit OTT for this one, but it's something I've been working on anyway..
Here's a Grid Fill GN group.
The illustrations may be a bit big to be useful.. but I'll try to summarize the method:
The job of the above sub-group is 1: to return the indices at the ends of rows and columns for each point in a given grid: e.g. (3,45) in X, (14,20) in Y, for point 17, below. 2: to associate each point in the perimeter with numbers in a continuous loop:
That group is used in a 'Basic Grid Fill':
.. which sends the perimeter of the grid to the target edge-loop, using the indices generated by (2, above), and interpolates the locations of the inner vertices between the new locations of their row and column ends. (1, above) .
The final Grid Fill group adds an interface, exposing an 'Offset', which rotates the grid with respect to the target loop, and 'Span Bias', which allows you to select any of the ratios of X and Y in the grid, having the right number of vertices in its perimeter.
This shows those parameters being adjusted
Further work could be done making the sigmoid bias in interpolation (currently provided by Map Range 's 'Smooth Step') more controllable. I doubt very much it's unbreakable; if anyone wants to use it, and breaks it, please leave a comment.