Vis Automations · In-app tool, Automation Scripts menu

Fastener Stacks

Finds every fastener in an assembly, groups touching fasteners into stacks, groups identical stacks into families, and shows each family as a colored Vis group you can select.

Verification passing on Vis 2606.0 build 26134 + 2606.2610 · 2026-10-29 · repo tc-vis-automation 9f1b0af · Goals 1 to 6 verified from inside Vis and headless (16/16); the bonus goals are not started.

Definitions

Fastener

An instance whose part number matches a fastener pattern in fastener_stacks.json (HL, HST, NAS, MS2, BACB and so on). An optional size fallback treats small unmatched parts as fasteners too; it is off by default.

Stack

Fastener instances whose bounding boxes touch within a tolerance (pin and collar, bolt, washer and nut). A lone rivet is a stack of one.

Family

Stacks with the same part numbers in the same order along the fastener axis, read either way round.

The steps

Walk

From the root: a fastener-named node is an instance (its bodies are not visited); any other node with children is descended into; a childless node is an instance itself. Walking every body instead cost about 29k COM calls and 288 s on the wing flap; walking instances brought it to 134 s.

Stack

Union-find over a spatial grid: two instances join when their bounding boxes touch within touch_tolerance.

Order

The stack axis is the line between the two farthest bounding-box centres; for a single instance, its local X axis (HL pins lie along local X). Members are ordered along it.

Sign

A family signature is the ordered part-number list, the same whichever end it is read from.

Show

One Vis group per family. Each family gets its own color from a golden-ratio hue walk in two lightness bands, so neighbors differ, set on every instance’s own material (about 0.1 s each). Group.Material reads back right but renders wrong across families, so it is not used.

Rules, no code change needed

Edit inapp/fastener_stacks.json for another assembly.

Key Default Meaning

fastener_patterns HL, HR, HST, HLT, CCR, CR, NAS, NASM, MS2, AN, BACB, BACN, BACW, BACR, BACS Regexes matched against the instance name from the start.

touch_tolerance 0.005 Model units. 0.0 to 0.02 gave identical stacks on the wing flap.

size_fallback false When true, unmatched parts at or below fastener_max_size are fasteners.

fastener_max_size 2.0 Largest bounding-box side, model units.

group_name_prefix Stack group Name of each Vis group the tool creates.

Key	Default	Meaning
`fastener_patterns`	HL, HR, HST, HLT, CCR, CR, NAS, NASM, MS2, AN, BACB, BACN, BACW, BACR, BACS	Regexes matched against the instance name from the start.
`touch_tolerance`	0.005	Model units. 0.0 to 0.02 gave identical stacks on the wing flap.
`size_fallback`	false	When true, unmatched parts at or below fastener_max_size are fasteners.
`fastener_max_size`	2.0	Largest bounding-box side, model units.
`group_name_prefix`	Stack group	Name of each Vis group the tool creates.

Vis facts it relies on (EXERCISED)

Selection, visibility and color must target the instance (a body’s Parent). Selecting a body raises a modal “Selection/Visibility Error” that blocks every later COM call.
Node.Selected = True replaces the selection, so lists are built with AppendNode on an empty SelectedNodes list.
GlobalTransformation is row-major with the translation in elements 12 to 14.

Outputs

<model>_stacks.json and .csv plus an HTML report, in Documents\VisFastenerStacks by default.

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