I was just randomly reading on the web about Geometric modeling kernels.
Is SketchUp modeling kernel proprietary, or is it ACIS or a fork of it?
Should/could SketchUp have a change and use Parasolid as geometric kernel?
https://en.wikipedia.org/wiki/Geometric_modeling_kernel
https://en.wikipedia.org/wiki/Parasolid
SketchUp creates plain old face geometry.
I don’t believe one can swap kernels. Probably SketchUp uses a custom engine, of which previous incarnations were presumably based on Intrinsic Alchemy 3 (which seems to have totally vanished from the internet as if it had never existed). By the way, also Google Earth uses it.
See here:
https://sketchucation.com/forums/viewtopic.php?f=180&t=49834
Note that the reference during startup does not appear anymore in modern SketchUp versions.
It probably already happened inside SketchUp, but we never noticed it… they used Alchemy 3 back in 2003 (thank you for the link), or, at least, part of it.
I’m wondering what’s SketchUp core today and if it suits well for the near future.
Other did this kernel swap: Vectorworks switched for Parasolid back in 2009
I should have said, one can not easily change paradigms. But still, even changing a polygon modeling kernel by another one is a huge endeavor, since they might have different APIs and data structures.
SketchUp’s geometry kernel is unique to SketchUp, as is it’s display pipeline. We decided early on that it was more flexible, efficient and affordable for us to develop these components on our own rather than entering into expensive and restrictive licensing deals for them.
Over the years, we have iterated many times on both of these components, leading to improvements in performance and reliability orders of magnitude better than our original code. We’ve been able to closely tune both our geometry kernel and display for SketchUp’s way of thinking and working, and that’s just the way we like it.
We could always (theoretically) implement some other/different/new geometry kernel; implementing NURBs, or SubD or one of the big parametric kernels like ACIS or Parasolid… but in doing so we’d really be building an entirely new kind of modeler that wasn’t SketchUp any more.
Thank you for clarify John.
As user I agree with you, I recon the power of SketchUp’s way of thinking and working, and I love it. I was just wondering where all it comes from 
My concern is that, today, many SketchUp geometric expansions features rely on third-party plugins, developed by very talented developers (Curviloft, SubD, Soap Skin & Bubbles, etc.).
Wouldn’t it be better to integrate some of the libraries used by these plugins inside the SketchUp kernel and then have something like you did for the Sandbox or Bezier Curve tools? I mean, complex geometric features in a SketchUp way.
These plugins implement their libraries on their own. They try to “emulate” continuous surfaces (e.g. bezier surfaces) on top of a polygon kernel. Sandbox and Bezier Curve do just the same (they are also plugins).
The Open Source Credits (accessible via the SketchUp About dialog,) might indicate some parts of SketchUp are (or were) based upon OpenCASCADE (or some part thereof) ?