Some friends were discussing this in a private chat yesterday. These are my comments. Very curious to hear responses.
When he goes through the example w/ the statue, isn't the whole time comparison invalidated?
The first two times it's sliced for a .4 nozzle and 2 shells
After he makes the rib cuts it's sliced for a .8 nozzle and 1 shell
Listen starting from 5:25
I mean, yeah, eliminating an entire toolhead trip around the shape will definitely reduce your time, totally irrespective of the ribs
Which doesn't mean the modeling technique is useless, but it's being oversold
Very similar to how I'd say that video and some of the similar ones, like the link he has pinned in comments, are downplaying the limited applicability of the whole discussion
These are all feasible vase prints
Which is a fairly specific topological shape
E.g., that other video (by Nerys?) declares he's going to show the technique on "a complex shape"
But the demo is a nosecone, which is about as simple of a shape you can get (setting aside the underlying formulas that might define the shape)
It needs no supports, has no meaningful bridging, etc
I wouldn't pitch the rib cuts as a technique for time saving per se
What they're doing is enabling a stronger thicker vase spiral
E.g., say I want a hollow cylinder
Easy enough to vase print
But now say I want the cylinder wall 4mm thick instead of whatever fraction of a mm my nozzle is
I can do that w/ one through seam (the one full cut he discusses)
But the interior space will be empty, so it's not going to be strong
In particular, the two walls are going to be connected solely along the through seam, so they'll be subject to a lot of torquing and such relative to each other
Making the partial cuts forces the vase spiral though to connect the two walls
So it's much stronger than the vase print alone
No more or less than that
It's actually added time compared to just the baseline vase print
Note also that there's an interesting property
These forced infill lines are necessarily two lines thick---the out and back required to connect the shells and then resume
That's going to have different, and probably less desired, strength properties than traditional infill
Which for the same amount of plastic & time would spread the lines evenly rather than having 2x strength infills at twice the distance
For a lot of shapes the doubled infill traversal is also maybe going to work out to being the same time cost as standard infill traversals
Especially if the printer can make traversals meaningfully faster than it can deposition
Also worth noting that all of this basically defeats the one purpose of a vase print: To have no seams
Sure, the forced infill cuts are on the interior so in many cases they won't matter
But the through cut necessary to go from outer to inner is going to make a seam that's at least as noticeable as the standard z shift if you just did a standard slice with one shell
Related topic, something I was just playing with recently and made a huge mess
if you're looking to strengthen prints without incurring the weight or time of infill or thicker shells, you can fill it with expanding foam
But don't use home repair style spray foam
Use a two part foam, like these
https://www.smooth-on.com/product-line/foam-it/
The spray stuff won't cure properly inside a void, it needs oxygen so only the top layer will cure
Two-part expanding foam will
So you could, e.g., print a double walled vase, and then fill the interior between them with expanding foam
This gets done in some high power amateur rocketry
Either strengthening a nosecone made of a simple shell (3d printed or fiberglass or whatever)
Or filling the fin canister assembly, thus locking the motor mount, fins, and body tube in position extremely rigidly
Big downside on the two-part foams is they have a very finite shelf life, especially after you open the component containers
So they're not something you can really keep around just in case you might want it some day
