Learning Curves: How Simple Splines Help Designers Model Complex 3D Forms | Hacker News Reader

Learning Curves: How Simple Splines Help Designers Model Complex 3D Forms

99percentinvisible.org

44 pointslouis-paul6 comments

> “Will this trend lead to haptic computer modeling interfaces, as tactile and accessible as folding cardboard, molding clay, or bending a strip of wood?”

The most interesting point of the article for me.

I'd never really considered how intuitive/organic it can be for humans to create three dimensional shapes, and how few of these techniques are in use with 3d modelling (although I haven't had any experience with 3d modelling in the last 8 years)

Splines are so intuitive that I remember using them pretty effectively in elementary school. Can we get there with 3d modelling? What will that look like?

Spline and sphere-based organics rendering has been done since the 90s. Softy3D is the software you would be looking for.

Subdivision modeling with polygons is essentially the same concept as splines (creating algorithmically smoothed shapes from a limited number of control points). It's been around since like the 70s -- the Catmull-Clark (yes, those Catmull and Clark) subdivision algorithm was invented in 1978! And it's been the main way of creating 3D models for film and games since at least the mid to late 90s -- ever since 3D workstations got powerful enough to display polygon models in realtime and games started using normal mapping. For films, the first major studio production to have made use of it seems to be Pixar's Geri's Game, and Gollum from the LOTR trilogy is sort of famously held to be the last character from a big movie to have been made with the older NURBS modeling tech.

It's extremely powerful for organic objects like creatures, but complex shapes and objects combining sharp and smooth features can run into problems with polygon flow and topology where the smoothing algorithm will run into problems. So I'm not saying it's the complete solution to what you're looking for.

In the last 10 years it's been increasing replaced by digital sculpting techniques, which make use of the same math but tend to get around the problems by throwing a lot more polygons at them. Bundled with a suitable UX there's probably a lot of potential for something elementary-school-level-yet-powerful in those. Feature-wise the most powerful at the moment is ZBrush, but the esoteric interface and workflow is probably preventing true mainstream adoption. Seriously -- you thought Blender was unintuitive? But ZBrush is used in like every game and animation studio, because nothing else comes close in terms of tools and performance.

Unless I'm mistaken, in boatbuilding spline weights are used to hold wooden battens on a drafting table. I've never heard of weights being hung from splines to get curves, either when lofting or building.

Spline weights (aka "Ducks") are for 2-D drafting. Here's a link that shows what they look like: https://edsonmarine.com/products/boating-accessories/spline-...

And if you're curious to see what hung weights look like, check out Gaudí’s Hanging Chain Models from 1889: http://dataphys.org/list/gaudis-hanging-chain-models/

I'm familiar with both of those. What I've not seen is hanging weights used to generate curves in boatbuilding, which is what's suggested in the article.

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