You may have seen this image before (hard to attribute, my best guess is from the link below):
The two corners look and feel different, but why? The difference is in degrees surface continuity,
Surfaces can be connected at different levels of continuity. The most common levels are G0, G1, G2, and G3. There are a lot of videos and articles online and I’m linking a few below, but there’s nothing better than seeing the difference with your own eyes and feeling it with your fingers.
This model is a sample of the four most common levels of continuity.: G0 (a straight joint), G1 (an arc), G2 (a spline with two collinear control points on each side), and G3 (same but with three control points). Print the model, and you will see and feel the difference.
After that, come back and read and watch more from the link given below.
gentle introduction
As far as I can tell, this article is the source of the above image: https://hackernoon.com/apples-icons-have-that-shape-for-a-every-good-reason-720d4e7c8a14
On the aesthetics of continuity, my personal favorite: https://www.core77.com/posts/12752/a-periodic-table-of-form-the-secret-language-of-surface-and-meaning-in-product-design-by-gray-holland-12752
going deeper
Freya Holmer’s incredible video on splines and continuity in general:
Or more implemented in this video using Fusion:
And here’s an example of the quite involved surface work by Andrew Jackson (the entire channel is made of solid gold):
The final video is quite advanced, but the path to getting to this surface level starts with just learning what consistency feels like.
This model will help you start your journey. Best wishes!
P.S.: 3D printing has an added benefit of super-smooth corners that is not covered in the video and link above. Apart from the pure aesthetics of the surface, the G3 continuous corners mean that the print head experiences smooth acceleration when printing such corners. This eliminates any possibility of ringing, which improves the appearance of the printed model and can improve printing speed.
The author marked this model as their own original creation.