Possible Points Numbering Glitch?

Grasshopper
1

Hi All,

I have been working on a file that will construct a basic box from the XYZ coordinates of each the vertices of each part.

I have all the panels created with a Hull3D operation and then the Mesh faces joined and simplified into the least number of faces per Brep, in this case 6 as I am just looking for a basic cuboid shape.

Brep Creation and Explosion
Brep Creation and Explosion1920×1040 188 KB

Next I have labelled the faces to help me work on my next operations, however when I move the points in Rhino the face numbers are all reissued seemingly randomly, and not just for the points that have been moved, for lots of the other faces too.

Centeroid Point Number 1
Centeroid Point Number 11920×1160 117 KB

Centeroid Point Number 2
Centeroid Point Number 21920×1160 127 KB

I was under the impression that if all the original points were referenced in the same order (which they have been for each panel, by hand, ie bottom left front, bottom left rear, bottom right rear, bottom right front, top left front, top left rear, top right rear, top right front) then the vertices, faces and edges should all adhere to the same numbering when the Brep is deconstructed and they are retrieved as a list item?

Have I broken it or am I doing something foolish?

Many thanks in advance.

2

check out the following components:

Box 2Pt
Bounding Box
Box Corners

box.gh (8.8 KB)

using those box-related components should give you persistant face numbering.

(hopefully - otherwise post a file that proves the opposite)
kind regards -tom

3

Hi Tom,

Unfortunately that method won’t work with what I am trying to achieve as I am hoping to eventually use this for shapes that are not cuboid.

Is there a way to ‘rebuild’ a Brep to give it this consistency?

Many thanks

4

your initial post:

now ?

for complex Breps you can not rely on a consistent face numbering.

you might be able to identify the faces by their normal ?

post a file / an example please (.3dm and .gh)

5

Apologies, my explanation was unclear, I mean I am looking for a basic cuboid shape for now, but I would like to be able to tackle other shapes with the same file later on, which is why I have based it all on the vertices, as this list can be endless and cover any shape.

I have got the Starling plugin in this file, it is running the convex hull operation.

I have also grouped the points onto layers in the 3dm file as I’m not sure that the link to their containers will persist through this transfer. The end game of course is to bring in coordinates from outside so the point containers are just a stop gap.

Thanks again for your help!
Convex hull.3dm (87 KB)
Convex hull.gh (42.9 KB)