EDARB(nged)

edit ARB primitive faces, edges, and vertices

📅 published 7.44.0, from nixpkgs unstable

💅 EDARB — the nged girlie's guide to editing ARB primitives ✨

okay so bestie, this is edarb, a user command from the BRL-CAD manual pages, filed under nged. It's the command you reach for when you want to directly mess with ARB geometry — no cap. 🫶

✨ NAME ✨

edarb — edit ARB primitive faces, edges, and vertices. literally what it says on the tin. 💖

🎀 SYNOPSIS 🎀

edarb edgedir  arb edge delta_x delta_y delta_z
edarb edgedir  arb edge rot fb
edarb extrude  arb face distance
edarb facedef  arb face [a|b|c|d parameters]
edarb mirface  arb face axis
edarb permute  arb tuple

🦋 DESCRIPTION 🦋

So the edarb command gives you a whole lil toolkit of subcommands for editing ARB (arbitrary polyhedron) primitives directly — like, you're grabbing the geometry by the edges and moving it yourself. You can move edges, extrude faces, redefine faces, mirror faces, or permute the vertex numbering. iconic behaviour honestly. 👑

The arb argument names the ARB object you wanna edit. that's your main character.

🌸 Subcommands 🌸

edgedir arb edge delta_x delta_y delta_z

Move the specified edge of arb by the given delta vector, in model coordinates. the edge is identified by its 1-based index number. every plane that gets affected by moving that edge is recalculated so it stays planar — she keeps it tidy. 💅

edgedir arb edge rot fb

Set the direction of the specified edge using rotation angle rot and front-back angle fb (both in degrees). the edge gets moved in the computed direction. 🧚

extrude arb face distance

Project the specified face of arb outward by distance (in current working units) along the face normal — so you're extruding the ARB shape. ⚠️ only available for ARB4, ARB6, and ARB8 types, bestie. not everything gets the glow-up.

facedef arb face [a|b|c|d parameters]

Redefine the specified face of arb by handing over a brand-new plane definition. the face is identified by the product of its vertex numbers (e.g., face 1234 uses product 24). math girl summer. 🍓

The plane definition method is picked with a letter:

  • a — planar equation: A B C D (normal vector components and offset)
  • b — three points: X1 Y1 Z1 X2 Y2 Z2 X3 Y3 Z3
  • c — rotation/front-back angles plus a fixed point or vertex
  • d — same plane normal direction, but shifted through a new fixed point

and like, if you give fewer arguments than the chosen method needs, the command prompts you for the missing values (interactive mode, very let's-do-it-together of her). 💬

mirface arb face axis

Mirror the specified face of arb across the specified axis (x, y, or z). reflection era. 🪞

permute arb tuple

Permute the vertex numbering of arb according to the specified tuple, which specifies the new vertex ordering. the minimum tuple length varies by ARB type: ARB4: 3, ARB5/6: 2, ARB7: 1, ARB8: 3. know your type, know your tuple. 💀

🔥 EXAMPLES 🔥

Example 1. Move an edge using a delta vector

mged> edarb edgedir arb8_1 12 10 0 0

Moves edge 12 (between vertices 1 and 2) of arb8_1 by +10 units in X. all affected face planes get recalculated. slay. ✨

Example 2. Move an edge using rotation angles

mged> edarb edgedir arb8_1 12 45 0

Sets the direction of edge 12 using azimuth 45°, elevation 0°. 🧭

Example 3. Extrude a face

mged> edarb extrude arb8_1 1234 50

Projects face 1234 (vertices 1, 2, 3, 4) of arb8_1 outward by 50 units. push it out, bestie. 🫸

Example 4. Redefine a face by plane equation

mged> edarb facedef arb8_1 1234 a 0 0 1 100

Redefines face 1234 of arb8_1 to be the plane with normal (0,0,1) at offset 100 (i.e., the Z=100 plane). ate. 💜

Example 5. Mirror a face

mged> edarb mirface arb8_1 1234 z

Mirrors face 1234 of arb8_1 across the Z axis. 🌈

Example 6. Permute vertex numbering

mged> edarb permute arb8_1 321

Permutes the vertex numbering of arb8_1 according to the tuple 321. reorder the whole vibe. 🔄

👀 SEE ALSO 👀

arb(nged), sed(nged) — go read those too, iykyk. 📚

💖 AUTHOR 💖

BRL-CAD Team — the actual legends behind all this.

🙈 BUG REPORTS 🙈

Found a bug? a problem? a genuine oopsie? Reports of bugs or problems should be submitted via electronic mail to devs@brlcad.org. don't be shy, they wanna know. 💌

ngl this whole page comes from the BRL-CAD manual — that's the source, and EDARB(nged) is the entry. mwah, go edit some geometry bestie 💅🎀🦋
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