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Splitting a NURBS surface "in half" is an insanely complicated operation, and the way you do it almost certainly depends on your intended use case. If you can'

Splitting a NURBS surface "in half" is an insanely complicated operation, and the way you do it almost certainly depends on your intended use case. If you can't find a library (or engine) in your domain that has the operation, then you're kind of S.O.L., and have to start from first principles. I don't blame commercial results and SEO for this. It's not like you used to be able to see a menu of rich choices for this, and now they're lost in the noise of companies with a mission.

ghgfhgfhn 7y ago
Well. Ideally I would like an introduction to the mathematics manipulating nurbs surfaces at the top of the search results. That's not too much to ask is it?
jlarocco 7y ago
> Splitting a NURBS surface "in half" is an insanely complicated operation, and the way you do it almost certainly depends on your intended use case. It's actually not "insanely complicated", and there are resources around, like https://pages.mtu.edu/~shene/COURSES/cs3621/NOTES/spline/NURBS-knot-insert.html https://pages.mtu.edu/~shene/COURSES/cs3621/NOTES/spline/NUR... and https://www.amazon.com/NURBS-Book-Monographs-Visual-Communication-ebook/dp/B000U0OXHG https://www.amazon.com/NURBS-Book-Monographs-Visual-Communic... > It's not like you used to be able to see a menu of rich choices for this, and now they're lost in the noise of companies with a mission. I mentioned just yesterday that DDG results are better for me, and this case is an example. "NURBs splitting algorithm" turns up a bunch of results.
- VikingCoder 7y ago
  > It's actually not "insanely complicated" Hi, your first link talks about NURBS curves, not NURBS surfaces. Cutting a surface in half is significantly more complicated than cutting a curve in half. And your second link is to a commercial result, an entire book. Presumably because the topic is complicated enough that people are willing to pay $69 to $78 to understand the challenge well enough. If your DDG search for "splitting a NURBS surface in half" are successful, I'd love to see the results.
  - phkahler 7y ago
    >> Cutting a surface in half is significantly more complicated than cutting a curve in half. No, it's actually the Exact same thing. Just applied independently to each of the curves in one direction. But none of that is really important. 15 years ago it would be trivial to learn how to do it with a Google search. Today not so. Also, a book result is still better for me than the commercial tool links which contain no math or theory what so ever.
    - VikingCoder 7y ago
      > No, it's actually the Exact same thing. Just applied independently to each of the curves in one direction. I can easily imagine situations where I would not be happy with that result. If that works for you, that's great. > Also, a book result is still better for me than the commercial tool links which contain no math or theory what so ever. Searching Google for "NURBS Book", "NURBS Course", "NURBS filetype:pdf" all work great for me. At a guess, most of the people who use Google are using tools, not making them. Yes, Google favors results that make the majority happy. I see that as a feature. If I'm in the minority, yes, I do need to become a more sophisticated searcher.
- lostmsu 7y ago
  I am using DuckDuckGo too, but to be fair the first result in Google on that exact query seems relevant: https://computergraphics.stackexchange.com/questions/340/splitting-of-nurbs-curves https://computergraphics.stackexchange.com/questions/340/spl...
m463 7y ago
A better example would probably be to search for a way to fix something on your car. The results are overwhelmingly skewed towards selling you the part vs instructions.

ghgfhgfhn 7y ago

Well. Ideally I would like an introduction to the mathematics manipulating nurbs surfaces at the top of the search results. That's not too much to ask is it?

jlarocco 7y ago

> Splitting a NURBS surface "in half" is an insanely complicated operation, and the way you do it almost certainly depends on your intended use case. It's actually not "insanely complicated", and there are resources around, like https://pages.mtu.edu/~shene/COURSES/cs3621/NOTES/spline/NURBS-knot-insert.html https://pages.mtu.edu/~shene/COURSES/cs3621/NOTES/spline/NUR... and https://www.amazon.com/NURBS-Book-Monographs-Visual-Communication-ebook/dp/B000U0OXHG https://www.amazon.com/NURBS-Book-Monographs-Visual-Communic... > It's not like you used to be able to see a menu of rich choices for this, and now they're lost in the noise of companies with a mission. I mentioned just yesterday that DDG results are better for me, and this case is an example. "NURBs splitting algorithm" turns up a bunch of results.

VikingCoder 7y ago
> It's actually not "insanely complicated" Hi, your first link talks about NURBS curves, not NURBS surfaces. Cutting a surface in half is significantly more complicated than cutting a curve in half. And your second link is to a commercial result, an entire book. Presumably because the topic is complicated enough that people are willing to pay $69 to $78 to understand the challenge well enough. If your DDG search for "splitting a NURBS surface in half" are successful, I'd love to see the results.
- phkahler 7y ago
  >> Cutting a surface in half is significantly more complicated than cutting a curve in half. No, it's actually the Exact same thing. Just applied independently to each of the curves in one direction. But none of that is really important. 15 years ago it would be trivial to learn how to do it with a Google search. Today not so. Also, a book result is still better for me than the commercial tool links which contain no math or theory what so ever.
  - VikingCoder 7y ago
    > No, it's actually the Exact same thing. Just applied independently to each of the curves in one direction. I can easily imagine situations where I would not be happy with that result. If that works for you, that's great. > Also, a book result is still better for me than the commercial tool links which contain no math or theory what so ever. Searching Google for "NURBS Book", "NURBS Course", "NURBS filetype:pdf" all work great for me. At a guess, most of the people who use Google are using tools, not making them. Yes, Google favors results that make the majority happy. I see that as a feature. If I'm in the minority, yes, I do need to become a more sophisticated searcher.
lostmsu 7y ago
I am using DuckDuckGo too, but to be fair the first result in Google on that exact query seems relevant: https://computergraphics.stackexchange.com/questions/340/splitting-of-nurbs-curves https://computergraphics.stackexchange.com/questions/340/spl...

m463 7y ago

A better example would probably be to search for a way to fix something on your car. The results are overwhelmingly skewed towards selling you the part vs instructions.