4 ms·

Polyhedral Splines

118 points by app4soft 3y ago

andybak 3y ago
This might be a better place to start: https://uf-cise-surflab.github.io/blender-polyhedral-splines-web/ https://uf-cise-surflab.github.io/blender-polyhedral-splines...
- dang 3y ago
  Ok, we've changed to that from https://projects.blender.org/blender/blender-addons/issues/91180 https://projects.blender.org/blender/blender-addons/issues/9... above. Thanks!
  - andybak 3y ago
    Hmmm. My link was for context, but the original link had more meat in some ways
    - dang 3y ago
      Ok, I've put the submitted URL back above.
themodelplumber 3y ago
> Blender currently provides no convenient spline creation, modeling, or reshaping tool Wow, I remember this recurring extra-modeling-schemes conversation about Blender, and other FOSS mesh modelers from at least 2003...? Lol. (In 2D land, Inkscape actually retains a few of these various convenient add-on vector drawing methods to this day) The 3D modeling pitches were also always supported by CAD folks, who were looking to sideload about 10 tons of CAD kernel onto the latest parametric undertaking. Like, give us infinite modeling accuracy and resolution or give us death! One issue here is this scrappy, Blender-style "whatever works in the final cut" Hollywood mindset [1] vs. the "can I recommend this, as a platform, to all of my friends" mindset in which all contingency needs must be covered, and so Blender is never, ever good enough for you, maybe. Or perhaps the "model itself must be exported directly to high-accuracy industrial plans" mindset. The former is easier on FOSS teams. The latter always invites this "fork it" mentality and you sometimes get these temporary Frankensteinian spinoffs called "AutoBlenderCAD 3D", etc. Also reminds me of JPatch? And some other third-party FOSS projects, RIP... And: Cool if it turns into something great, even if for a while! 1. https://youtu.be/AE_5QyBykgg https://youtu.be/AE_5QyBykgg
- app4soft 3y ago
  You might be interested to read thread:[0] [0] https://fosstodon.org/@pafurijaz@mstdn.social/110714437009467695 https://fosstodon.org/@pafurijaz@mstdn.social/11071443700946...
- somat 3y ago
  > Blender currently provides no convenient spline creation, modeling, or reshaping tool I suspect it is a bit of hyperbole on the part of the original poster. as Blender has had NURBS surfaces since.. well forever. However nurbs surfaces are very difficult to use in a reasonable manner. As a workable alternative Blender has subdivision surfaces. which as far as the end user is concerned are splines that actually integrate well with mesh geometry. That specific quote initially led me to dismiss the thread as someone jumping in without understanding blender at all. But I read the whole thread. And my personal conclusion(which does not matter a snot with regards to blender development) is that the original poster wants some poorly defined property that existing spline implementations don't provide(I suspect that if I were more familiar with splines this property would be obvious) and most importantly is willing to provide the dev time required to bring it to blender. So as a occasional blender user I welcome improvements to splines. In regards to modeling workflow. Realistically, something like blender is good enough for most projects. but my heart lies with constraint based pad and pocket parametric cad. it fits the way I think better.
  - themodelplumber 3y ago
    It's that word "convenient" doing all the lifting, carrying years of depressing threads about how much more epic the NURBS implementation could be, if only, etc.
    - glompers 3y ago
      Nurbs noobs, unite: all you have to smoothe is your domains!
  - agumonkey 3y ago
    present but hard is a classic issue, long ago 3dsmax (v2) got nurbs modeling too, but limited and slow.. you'd assume that's the norm, until you hit alias waavefront software where it's fast and intuitive. game changer
lightedman 3y ago
I remember waaaay back in the day doing spline 3D modeling via Softy3D. Those were some fun times. I'd like to see that added into Blender some day.
- app4soft 3y ago
  > spline 3D modeling via Softy3D Here is the only link googled.[0] From the latest such apps look on Seamless3D.[1] [0] https://cs.gmu.edu/~jchen/graphics/book/tools/softy3d.htm https://cs.gmu.edu/~jchen/graphics/book/tools/softy3d.htm [1] https://www.seamless3d.com/ https://www.seamless3d.com/
mjhay 3y ago
How fast can they be reticulated?
- glompers 3y ago
  I'll upvote a Maxis tribute comment as a fellow SimCity2000 fan, and also because the point at which the game voiced, "reticulating splines..." was the relevant point at which it made sure your map landform percentiles connected into a surface of either buildable or slopable terrains
virtualritz 3y ago
OpenSubdiv supports conversion of an input control polyhedron into such patches that describe the limit surface (on CPU and GPU). But AFAIK it will generate a variety of patch types (not just regular b-spline) to accurately represent extraordinary vertices and non-quad base faces.[1] In general such representations are hard to manipulate. Stitching cubic patches ensuring C2 or C3 continuity is how we did organic modeling before the advent (or re-discovery, rather) of subdivision surfaces. E.g. the dinosaurs in "Jurassic Park" were modeled from stitched NURBS patches. [1] https://graphics.pixar.com/opensubdiv/docs/bfr_overview.html https://graphics.pixar.com/opensubdiv/docs/bfr_overview.html

118 points by app4soft 3y ago

This might be a better place to start: https://uf-cise-surflab.github.io/blender-polyhedral-splines-web/ https://uf-cise-surflab.github.io/blender-polyhedral-splines...

dang 3y ago
Ok, we've changed to that from https://projects.blender.org/blender/blender-addons/issues/91180 https://projects.blender.org/blender/blender-addons/issues/9... above. Thanks!
- andybak 3y ago
  Hmmm. My link was for context, but the original link had more meat in some ways
  - dang 3y ago
    Ok, I've put the submitted URL back above.

themodelplumber 3y ago

> Blender currently provides no convenient spline creation, modeling, or reshaping tool Wow, I remember this recurring extra-modeling-schemes conversation about Blender, and other FOSS mesh modelers from at least 2003...? Lol. (In 2D land, Inkscape actually retains a few of these various convenient add-on vector drawing methods to this day) The 3D modeling pitches were also always supported by CAD folks, who were looking to sideload about 10 tons of CAD kernel onto the latest parametric undertaking. Like, give us infinite modeling accuracy and resolution or give us death! One issue here is this scrappy, Blender-style "whatever works in the final cut" Hollywood mindset [1] vs. the "can I recommend this, as a platform, to all of my friends" mindset in which all contingency needs must be covered, and so Blender is never, ever good enough for you, maybe. Or perhaps the "model itself must be exported directly to high-accuracy industrial plans" mindset. The former is easier on FOSS teams. The latter always invites this "fork it" mentality and you sometimes get these temporary Frankensteinian spinoffs called "AutoBlenderCAD 3D", etc. Also reminds me of JPatch? And some other third-party FOSS projects, RIP... And: Cool if it turns into something great, even if for a while! 1. https://youtu.be/AE_5QyBykgg https://youtu.be/AE_5QyBykgg

app4soft 3y ago
You might be interested to read thread:[0] [0] https://fosstodon.org/@pafurijaz@mstdn.social/110714437009467695 https://fosstodon.org/@pafurijaz@mstdn.social/11071443700946...
somat 3y ago
> Blender currently provides no convenient spline creation, modeling, or reshaping tool I suspect it is a bit of hyperbole on the part of the original poster. as Blender has had NURBS surfaces since.. well forever. However nurbs surfaces are very difficult to use in a reasonable manner. As a workable alternative Blender has subdivision surfaces. which as far as the end user is concerned are splines that actually integrate well with mesh geometry. That specific quote initially led me to dismiss the thread as someone jumping in without understanding blender at all. But I read the whole thread. And my personal conclusion(which does not matter a snot with regards to blender development) is that the original poster wants some poorly defined property that existing spline implementations don't provide(I suspect that if I were more familiar with splines this property would be obvious) and most importantly is willing to provide the dev time required to bring it to blender. So as a occasional blender user I welcome improvements to splines. In regards to modeling workflow. Realistically, something like blender is good enough for most projects. but my heart lies with constraint based pad and pocket parametric cad. it fits the way I think better.
- themodelplumber 3y ago
  It's that word "convenient" doing all the lifting, carrying years of depressing threads about how much more epic the NURBS implementation could be, if only, etc.
  - glompers 3y ago
    Nurbs noobs, unite: all you have to smoothe is your domains!
- agumonkey 3y ago
  present but hard is a classic issue, long ago 3dsmax (v2) got nurbs modeling too, but limited and slow.. you'd assume that's the norm, until you hit alias waavefront software where it's fast and intuitive. game changer

lightedman 3y ago

I remember waaaay back in the day doing spline 3D modeling via Softy3D. Those were some fun times. I'd like to see that added into Blender some day.

app4soft 3y ago
> spline 3D modeling via Softy3D Here is the only link googled.[0] From the latest such apps look on Seamless3D.[1] [0] https://cs.gmu.edu/~jchen/graphics/book/tools/softy3d.htm https://cs.gmu.edu/~jchen/graphics/book/tools/softy3d.htm [1] https://www.seamless3d.com/ https://www.seamless3d.com/

mjhay 3y ago

How fast can they be reticulated?

glompers 3y ago
I'll upvote a Maxis tribute comment as a fellow SimCity2000 fan, and also because the point at which the game voiced, "reticulating splines..." was the relevant point at which it made sure your map landform percentiles connected into a surface of either buildable or slopable terrains

virtualritz 3y ago

OpenSubdiv supports conversion of an input control polyhedron into such patches that describe the limit surface (on CPU and GPU). But AFAIK it will generate a variety of patch types (not just regular b-spline) to accurately represent extraordinary vertices and non-quad base faces.[1] In general such representations are hard to manipulate. Stitching cubic patches ensuring C2 or C3 continuity is how we did organic modeling before the advent (or re-discovery, rather) of subdivision surfaces. E.g. the dinosaurs in "Jurassic Park" were modeled from stitched NURBS patches. [1] https://graphics.pixar.com/opensubdiv/docs/bfr_overview.html https://graphics.pixar.com/opensubdiv/docs/bfr_overview.html