Latest revision as of 18:28, 15 January 2026

F4 Wiki

The public, stable reference for GD&T and how the F4 Application interprets it.

Each topic pairs standard GD&T guidance with F4 validation behavior so you can move from definition to decision quickly.

Quick links

Start here

GD&T Reference
Standard definitions, symbols, and usage guidance.

F4 Behavior
Rules, checks, and decisions used by the F4 validator.

Glossary and Examples
Short definitions and worked applications.

Browse by category

Form
Straightness, flatness, circularity, cylindricity.

Orientation
Parallelism, perpendicularity, angularity.

Location
Position, composite, MSS, concentricity, symmetry.

Profile
Line, surface, composite, MSS.

Runout
Circular and total runout.

Supporting rules Related guidance for modifiers and datum systems.

Featured pages

GDT:Straightness - basic line element form control.
GDT:Flatness - planar form control.
GDT:Position - primary location control for features of size.
GDT:Profile of a Surface - shape and location combined.
F4:Position Validation - how F4 checks position.

How to use this wiki

The public view shows approved revisions only.
Each GD&T page links to its matching F4 validation page.
Use the sidebar or search to find topics quickly.
When a rule needs interpretation, the F4 page calls out the decision and its impact.

Community

Community forum
Announcements, questions, feature requests, and showcases.

Messages
Direct messages between contributors.

@@ Line 2: / Line 2: @@
 = F4 Wiki =
-<div style="background: var(--f4-bg-panel); border: 1px solid var(--f4-border); border-radius: 12px; padding: 1.2em; margin-bottom: 1.2em;">
+{| class="f4-hero"
-<div style="display: flex; gap: 16px; align-items: center; flex-wrap: wrap;">
+| [[File:F4_Logo_White.svg|80px|frameless|link=Main_Page|alt=F4|class=f4-logo]]
-<div style="flex: 0 0 auto;">
+| '''The public, stable reference for GD&T and how the F4 Application interprets it.'''<br/>
-<img src="/resources/assets/logo-white.svg" alt="F4" style="height: 56px; width: auto;">
+Each topic pairs standard GD&T guidance with F4 validation behavior so you can move from definition to decision quickly.
-</div>
+|}
-<div style="flex: 1 1 320px;">
-<div style="font-size: 1.2em; font-weight: 600;">The public, stable reference for GD&T and how the F4 Application interprets it.</div>
+== Quick links ==
-<div style="margin-top: 0.4em;">Each topic pairs standard GD&T guidance with F4 validation behavior so you can move from definition to decision quickly.</div>
+* [https://f4.dev/ F4 website]
-</div>
+* [https://docs.f4.dev/ Documentation]
-</div>
+* [https://download.f4.dev/ Downloads]
-<div style="margin-top: 0.9em; display: flex; gap: 8px; flex-wrap: wrap;">
-<a href="https://f4.dev/" style="display: inline-block; padding: 6px 10px; border-radius: 8px; background: var(--f4-bg-surface); border: 1px solid var(--f4-border); color: var(--f4-text); text-decoration: none;">F4 website</a>
-<a href="https://docs.f4.dev/" style="display: inline-block; padding: 6px 10px; border-radius: 8px; background: var(--f4-bg-surface); border: 1px solid var(--f4-border); color: var(--f4-text); text-decoration: none;">Documentation</a>
-<a href="https://download.f4.dev/" style="display: inline-block; padding: 6px 10px; border-radius: 8px; background: var(--f4-bg-surface); border: 1px solid var(--f4-border); color: var(--f4-text); text-decoration: none;">Downloads</a>
-</div>
-</div>
-{| style="width: 100%; border-collapse: separate; border-spacing: 12px;"
+== Start here ==
+{| class="f4-card-grid"
 |-
-| style="vertical-align: top; width: 33%;" |
+| class="f4-card" |
-<a href="/index.php/Category:GDT_Reference" style="display: block; background: var(--f4-bg-panel); border: 1px solid var(--f4-border); border-radius: 10px; padding: 0.9em; text-decoration: none; color: var(--f4-text);">
+'''[[:Category:GDT Reference|GD&T Reference]]'''<br/>
-<div style="font-weight: 600;">GD&T Reference</div>
+Standard definitions, symbols, and usage guidance.
-<div style="margin-top: 0.4em;">Standard definitions, symbols, and usage guidance.</div>
+| class="f4-card" |
-</a>
+'''[[:Category:F4 Behavior|F4 Behavior]]'''<br/>
-| style="vertical-align: top; width: 33%;" |
+Rules, checks, and decisions used by the F4 validator.
-<a href="/index.php/Category:F4_Behavior" style="display: block; background: var(--f4-bg-panel); border: 1px solid var(--f4-border); border-radius: 10px; padding: 0.9em; text-decoration: none; color: var(--f4-text);">
+| class="f4-card" |
-<div style="font-weight: 600;">F4 Behavior</div>
+'''[[:Category:Glossary|Glossary and Examples]]'''<br/>
-<div style="margin-top: 0.4em;">Rules, checks, and decisions used by the F4 validator.</div>
+Short definitions and worked applications.
-</a>
-| style="vertical-align: top; width: 33%;" |
-<a href="/index.php/Category:Glossary" style="display: block; background: var(--f4-bg-panel); border: 1px solid var(--f4-border); border-radius: 10px; padding: 0.9em; text-decoration: none; color: var(--f4-text);">
-<div style="font-weight: 600;">Glossary and Examples</div>
-<div style="margin-top: 0.4em;">Short definitions and worked applications.</div>
-<div style="margin-top: 0.6em; color: var(--f4-accent);">Browse glossary and examples</div>
-</a>
 |}
 == Browse by category ==
-{| style="width: 100%; border-collapse: separate; border-spacing: 12px;"
+{| class="f4-card-grid"
 |-
-| style="vertical-align: top; width: 50%;" |
+| class="f4-card" |
-<a href="/index.php/Category:Form" style="display: block; background: var(--f4-bg-panel); border: 1px solid var(--f4-border); border-radius: 10px; padding: 0.9em; text-decoration: none; color: var(--f4-text);">
+'''[[:Category:Form|Form]]'''<br/>
-<div style="font-weight: 600;">Form</div>
+Straightness, flatness, circularity, cylindricity.
-<div style="margin-top: 0.4em;">Straightness, flatness, circularity, cylindricity.</div>
+| class="f4-card" |
-</a>
+'''[[:Category:Orientation|Orientation]]'''<br/>
-| style="vertical-align: top; width: 50%;" |
+Parallelism, perpendicularity, angularity.
-<a href="/index.php/Category:Orientation" style="display: block; background: var(--f4-bg-panel); border: 1px solid var(--f4-border); border-radius: 10px; padding: 0.9em; text-decoration: none; color: var(--f4-text);">
-<div style="font-weight: 600;">Orientation</div>
-<div style="margin-top: 0.4em;">Parallelism, perpendicularity, angularity.</div>
-</a>
 |-
-| style="vertical-align: top; width: 50%;" |
+| class="f4-card" |
-<a href="/index.php/Category:Location" style="display: block; background: var(--f4-bg-panel); border: 1px solid var(--f4-border); border-radius: 10px; padding: 0.9em; text-decoration: none; color: var(--f4-text);">
+'''[[:Category:Location|Location]]'''<br/>
-<div style="font-weight: 600;">Location</div>
+Position, composite, MSS, concentricity, symmetry.
-<div style="margin-top: 0.4em;">Position, composite, MSS, concentricity, symmetry.</div>
+| class="f4-card" |
-</a>
+'''[[:Category:Profile|Profile]]'''<br/>
-| style="vertical-align: top; width: 50%;" |
+Line, surface, composite, MSS.
-<a href="/index.php/Category:Profile" style="display: block; background: var(--f4-bg-panel); border: 1px solid var(--f4-border); border-radius: 10px; padding: 0.9em; text-decoration: none; color: var(--f4-text);">
-<div style="font-weight: 600;">Profile</div>
-<div style="margin-top: 0.4em;">Line, surface, composite, MSS.</div>
-</a>
 |-
-| style="vertical-align: top; width: 50%;" |
+| class="f4-card" |
-<a href="/index.php/Category:Runout" style="display: block; background: var(--f4-bg-panel); border: 1px solid var(--f4-border); border-radius: 10px; padding: 0.9em; text-decoration: none; color: var(--f4-text);">
+'''[[:Category:Runout|Runout]]'''<br/>
-<div style="font-weight: 600;">Runout</div>
+Circular and total runout.
-<div style="margin-top: 0.4em;">Circular and total runout.</div>
+| class="f4-card" |
-</a>
+'''Supporting rules'''
-| style="vertical-align: top; width: 50%;" |
+Related guidance for modifiers and datum systems.
-<div style="background: var(--f4-bg-panel); border: 1px solid var(--f4-border); border-radius: 10px; padding: 0.9em;">
+* [[:Category:Modifiers|Modifiers]]
-<div style="font-weight: 600;">Supporting rules</div>
+* [[:Category:Datums|Datums]]
-<div style="margin-top: 0.4em;"><a href="/index.php/Category:Modifiers" style="color: var(--f4-accent); text-decoration: none;">Modifiers</a> and <a href="/index.php/Category:Datums" style="color: var(--f4-accent); text-decoration: none;">Datums</a>.</div>
-</div>
 |}
@@ Line 90: / Line 68: @@
 == Community ==
-{| style="width: 100%; border-collapse: separate; border-spacing: 12px;"
+{| class="f4-card-grid"
 |-
-| style="vertical-align: top; width: 50%;" |
+| class="f4-card" |
-<a href="/index.php/Forum:Start" style="display: block; background: var(--f4-bg-panel); border: 1px solid var(--f4-border); border-radius: 10px; padding: 0.9em; text-decoration: none; color: var(--f4-text);">
+'''[[Forum:Start|Community forum]]'''<br/>
-<div style="font-weight: 600;">Community forum</div>
+Announcements, questions, feature requests, and showcases.
-<div style="margin-top: 0.4em;">Announcements, questions, feature requests, and showcases.</div>
+| class="f4-card" |
-</a>
+'''[[Special:UserBoard|Messages]]'''<br/>
-| style="vertical-align: top; width: 50%;" |
+Direct messages between contributors.
-<a href="/index.php/Special:UserBoard" style="display: block; background: var(--f4-bg-panel); border: 1px solid var(--f4-border); border-radius: 10px; padding: 0.9em; text-decoration: none; color: var(--f4-text);">
-<div style="font-weight: 600;">Messages</div>
-<div style="margin-top: 0.4em;">Direct messages between contributors.</div>
-</a>
 |}

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