Flipped surface normals

[chojii]

hi all
im aiming to model the beijing water cube and have had some issues with flipping the surface normals of the voronoi pattern. ive tried the numerous amounts of posts on the forum and nothing seems to work. any help is appreciated

im aiming to get the normals of the sides of the box (arrows inwards) face outwards. i want to make sure the boottom surface of the box is “gone” so i essentially created a rectangle, moved it and extruded it based on the z direction its moved in.

surfacenormals.gh (10.2 KB)

[Joseph_Oster]

@chojii

ive tried the numerous amounts of posts on the forum and nothing seems to work.

@chojii

im aiming to get the normals of the sides of the box (arrows inwards) face outwards. i want to make sure the boottom surface of the box is “gone”

Looks to me like you already have what you’re asking for? What am I missing?

[chojii]

looking at the sides of the cube, the normals are facing inwards, but would want it to face outwards. apologies! im pretty new to grasshopper.

[Joseph_Oster]

surfacenormals_2025Apr25a.gh (13.2 KB)

P.S. There was no need to flatten the ‘P’ input of Brep CP. And if you prefer to use the area centroids of the Voronoi cells, you can do that.

surfacenormals_2025Apr25b.gh (14.0 KB)

[chojii]

amazing, thank you so much! how would you be able to attach this to a mesh?

would it be just a matter of conencting the points to the voronoi pattern?

[Joseph_Oster]

@chojii

how would you be able to attach this to a mesh?

I have no idea what you mean? Please see “P.S.” in previous post.

[leopoldomonzani]

surfacenormals a.gh (12.2 KB)

[chojii]

thank you for the help! i was aiming to keep the surfaces on the voronoi pattern so i can later turn the cells into a mesh and inflate them.

[chojii]

i am aiming to take the voronoi cells and inflate it using kangaroo. how would you connect the pattern to create a mesh?

the individual cells are supposed to inflate.

[Joseph_Oster]

Have you changed your username since yesterday? I vaguely recall a different name.

I realized that using Bounding Box as I did yesterday (version ‘25b’) will fail if your “cube” is not aligned with ‘World XY’ so fixed that by using a capped box instead.

While I was at it, I changed the geometry being passed to PopGeo from the five faces of the “box” (DeBrep ‘F’) to the whole box (Brep Join ‘B’). This makes the points more evenly distributed on all faces so the Voronoi cells on the walls are closer in size to the cells on the top.

surfacenormals_2025Apr26a.gh (20.4 KB)

Then I decided to look at inflating the Voronoi cells, even though I am a dilettante at Kangaroo.

When I searched the forum for “inflate voronoi” I found many threads, including references to the Beijing Water Cube:

https://discourse.mcneel.com/search?q=inflate%20voronoi

This one from @HS_Kim in 2017:

Voronoi Bubbles

Hi. Attachment is an updated version using K2. Hope it helps. [Canvas at 15;55;48]Voronoi_Bubbles_re.gh (12.3 KB)

And this one from me last year, attempting to adapt @HS_Kim’s code:

Cellstruce / script with concave surfaces help

Without fully knowing what I’m doing, I hacked a plugin-free version of @HS_Kim’s Voronoi_Bubbles_re.gh in the other thread. [Voronoi_Bubbles_2024Aug16a] Voronoi_Bubbles_2024Aug16a.gh (18.0 KB) It has gaps between the cells, which perhaps are fixed at the end of HS_Kim’s code by the ‘Weaverbird Join Meshes and Weld’ component that I deleted? [Voronoi_Bubbles_2024Aug16a2]

I finally gave up so leave that part to you.