plugin.dev.lab

Track 1 · Concept

What order to use things in

Most of the difficulty in a Grasshopper plugin is not what exists — it is what comes next. This page answers that twice: the four panels in the ribbon, then the whole chain as a single diagram.

Where things sit in the ribbon

Bowl 23 components Bowl Analysis 9 components Table 4 components Util 8 components

Bowl builds geometry — start lines, sections, the 2D layout, the solids. Bowl Analysis measures what Bowl built: sightlines, C-values, seat maps, and the guides that make them legible. Table connects a workbook, so numbers live in Excel or Google Sheets instead of in sliders. Util is everything that helps without being part of the chain — a values panel, a legend, sheet setup, the license.

Inside a panel, the separators are the order of work. Read a panel left to right, section by section, and you are reading the sequence you would actually build in.

The whole chain in one diagram

The chain is not a single line: two strands run side by side — the plan and the section — and they meet at the 2D layout. Follow it left to right; every shape links to that component’s page.

Custom Startline stands in for Startline Custom Axis stands in for Axis Auto Section stands in for Section Table Section stands in for Section Plus Custom Seat stands in for Seat Field → Startline Startline → Axis Custom Startline → Axis Axis → Section Section → Section Plus Auto Section → Section Plus Section Plus → Section analysis Table Section → Section analysis Axis → Stand 2D Axis → View Axis Section Plus → Stand 2D Custom Axis → Stand 2D Field → View Limit Stand 2D → Vomitory Stand 2D → Stand 3D Stand 2D → Custom Seat Vomitory → Seat Seat → Cut Custom Seat → Cut Cut → Opening Cut Opening Cut → Vom 3D Vom 3D → Assemble Bowl Stand 3D → Assemble Bowl Assemble Bowl → Stand 3D Plus Assemble Bowl → View Limit Stand 3D Plus → Rail 3D Stand 3D Plus → C-value Seat Stand 3D Plus → C-value Tread Stand 3D Plus → Seat Map Rail 3D → C-value Seat Rail 3D → C-value Tread C-value Seat → C-value Map C-value Tread → C-value Map C-value Tread → C-value Section Check Seat Map → Seat View Field — Draws the playing field outline for a sport and the focal point every sightline is measured to. Field Startline Rect, Startline Capsule, Startline Oval — Start line for the front row, offset outward from the field edge by a long-side and a short-side distance. Startline Custom Startline — Start line taken from a curve you draw - aligned to the field frame for a preset field, used as drawn for a custom field. Custom Startline Auto Section — Works out the risers for you. Auto Section Section — Turns the tread lines you draw into a tier section — rows, nosing and eye points, and the closed profile the stand is swept from. Section Axis — Divides the start line into the planes each stand section is placed on. Axis Custom Axis — Section placement planes from axis curves you draw yourself. Custom Axis Table Section — Builds the tier sections from the numbers in your workbook instead of lines you draw. Table Section Section Plus — Adds the things a bare section does not have: the front barrier or handrail, accessible (wheelchair) rows, and the sightline check over the barrier. Section Plus Section analysis — Checks the sightline over the row in front, row by row, and reports the C-value. Section analysis View Axis — Tags every axis with its number — a guide line running out from each axis point into a circle holding the axis name (A0, A1, ...). View Axis Stand 2D — Sweeps each tier section around the axis planes and flattens it into tread rings in plan. Stand 2D Vomitory — Places the vomitories — the tunnels spectators enter the bowl through — in the tread rings, and sets how each one gets down to the concourse: flat... Vomitory Seat — Fills the tread rings with seats, breaking each row at the vomitories and aisles, and flags rows that break the egress limits. Seat Custom Seat — Same seat placement as Seat, but the vomitories, aisles and even the seats come from curves you draw instead of being generated. Custom Seat Stand 3D — Sweeps the closed section profile around the axis planes into the solid tier bodies. Stand 3D Cut — Cuts the bowl to shape — keep or remove a whole span between two axis numbers, or everything on one side of each curve you draw. Cut Opening Cut — Punches local entrance openings through the stand — between two axis numbers, or under a closed curve you draw. Opening Cut Vom 3D — Builds the vomitories as solids — the side and end walls, the portal opening punched through, and the stair or ramp down to the concourse. Vom 3D Assemble Bowl — Assembles the final bowl plan before Stand 3D Plus: merges parallel seat layouts (tiers renumbered) with their stand solids, and previews the... Assemble Bowl View Limit — Draws the optimum and maximum viewing distance circles for a sport and counts how many seats fall outside. View Limit Rail 3D — Builds the railings and parapets as solids — the front barrier, the rear parapet, the edges left by a cut, and the walls around entrance openings. Rail 3D Stand 3D Plus — Builds the 3D bowl: cuts the stand solids with everything the 2D chain decided — shape cuts, entrance openings, vomitories — and lifts the seats and... Stand 3D Plus C-value Seat — Paints every seat with its own C-value, measured in 3D from that seat's eye to its own focus. C-value Seat C-value Tread — Paints each tread band with the C-value of one representative section taken between two axes. C-value Tread Seat Map — Groups the seats into zones - the pieces left when the aisles, vomitories and cuts are taken out of the tier - and gives every seat a readable... Seat Map C-value Map — Lays the C-value map out flat - one sheet per tier, named TIER 1, TIER 2 and so on, with the seat layout drawing, the colored map and the tier's... C-value Map C-value Section Check — Lays every axis section out on its own sheet so you can flip through them. C-value Section Check Seat View — Looks through a spectator's eyes. Seat View

Arrows are the order you build in, and each is a wire you make on the canvas. The one from the axis into the section is Base Line: the start line as the axes facet it, which is what the section actually stands on. Dotted links mean “instead of”, not “as well as”: a custom start line replaces the built-in one; a table-driven section replaces the one you set by hand.

The stages

Stage 1

Plan & setup

Place the field, draw the line where the front row starts, and set the axes the sections will sit on. Everything downstream is measured from these.

The four start-line shapes form one continuum: grow the corner radius and a rectangle becomes a capsule, then an oval. A custom curve is the escape hatch when the shape is not any of those — open curves are allowed.

Field Startline Rect Startline Capsule Startline Oval Custom Startline Axis Custom Axis

Stage 2

Section

Build the stair section — the profile that gets swept around the bowl — and attach extras such as railings and wheelchair platforms.

There are three ways in. Read a line you drew, solve riser heights from a target C-value, or build the section from workbook numbers. All three produce the same object, and everything downstream cannot tell which way it came.

Section Auto Section Section Plus Table Section

Stage 3

2D layout

Unroll the section onto the plan, place vomitories and seats, and cut the bowl to shape.

Most design decisions happen here. This is where the bowl stops being a profile and becomes a seating plan: where people walk in, how many seats fit, where the geometry stops.

Stand 2D Vomitory Seat Custom Seat Cut Opening Cut

Stage 4

3D solids

Build what the 2D layout decided as real solids — tier stands, vomitory stairs, railings, seats.

From here the chain carries the 3D result inside a single bundled port, so the analysis stage needs one wire rather than many. Take it from the railings’ result, which carries the rest, and the railings are checked too.

Stand 3D Vom 3D Stand 3D Plus Rail 3D Assemble Bowl Seat 3D

Stage 5

Analysis

Check the design and produce evidence you can put in front of someone.

C-value is computed per seat and per tread band across the whole bowl, so you see where the design breaks down rather than checking one section and hoping. Section checks draw their dimensions and sightlines on the real cut — a number you report is a number you can defend.

A single-section check and the whole-bowl maps do not replace each other. One examines one place rigorously; the others tell you which place to examine.

Section analysis C-value Seat C-value Tread C-value Section Check C-value Map Seat Map Seat View View Axis View Limit

Alongside the chain

Tables

Values can live in a spreadsheet instead of Rhino. Read your inputs from a workbook, write the results back, and keep the numbers where the rest of the project already keeps them.

Google Sheets and Excel both work, and communication happens only when you press Run — the definition does not talk to the network while you are designing.

Excel Workbook Google Workbook Table In Table Out

Tools

Tools that sit beside the chain rather than in it — license registration, gathering inputs into one panel, legends, shared drawing-sheet format, and helpers for bundling per-tier values.

These are not a stage. They do not take the chain in and pass it on; they support whatever stage you are working in.

Input Panel C-value Legend Sheet Setup Slider Merge Toggle Merge Data Gate Gate Switch License