03-19-2022, 04:17 AM
(This post was last modified: 03-19-2022, 04:24 AM by Ottia Tuota.)
(03-18-2022, 08:54 PM)Ofnuts Wrote: ...
But of course it softens angles even where it is not wanted, but then on such angles a user would put tangents... So a possible criterion is to stop the smoothing on anchors where one or more tangents are defined, and of course, keep the tangents as boundary conditions.
Currently one can use a selection to exclude some anchors. But it could be automated just as you say. That is an idea. i must think about it.
(03-18-2022, 06:42 PM)Ottia Tuota Wrote:(03-18-2022, 06:20 PM)Ofnuts Wrote: Pretty cool. But any way to prevent loops?
No, except by changing the values for the parameters. Of course we could develop the theory further. I modified it to take into account edge lengths, and we could of course use some other criteria. The question is, what criteria, and who would do it ...
On the second thought, perhaps loops are unavoidable. Mathematically it is now building a big system of linear equations and then solving it. It comes down to inverting a big matrix, and that is easy. It seems to me that avoiding loops would mean that, in addition to equations, we should put there some inequalities to rule out unacceptable solutions. Might even lead to non-linear equations. I don't know how to do it, and anyway it would be quite a different problem.
One can of course do manual corrections to the resulting path, but that destroys G2-continuity locally, though the path can visually still be quite smooth. So perhaps we should just say that occasional loops are essential in the G2 job.
Changing parameters may help. But in that difficult example of yours, if we use the default values except that we put the second tuning parameter to 10, say, then there is no loop but all segments become almost straight and the sharp point is rounded only marginally. That is hardly what one would want. And the plugin "Simple smooth" makes a double loop. I leave this as an open question.