Latest revision as of 18:25, 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 =
-<htmltag tagname="div" style="background: var(--f4-bg-panel); border: 1px solid var(--f4-border); border-radius: 12px; padding: 1.2em; margin-bottom: 1.2em;">
+[[File:F4_Logo_White.svg|160px|frameless|link=Main_Page|alt=F4|class=f4-logo]]
-<htmltag tagname="div" style="display: flex; gap: 16px; align-items: center; flex-wrap: wrap;">
+''The public, stable reference for GD&T and how the F4 Application interprets it.''
-<htmltag tagname="div" style="flex: 0 0 auto;">
+Each topic pairs standard GD&T guidance with F4 validation behavior so you can move from definition to decision quickly.
-<htmltag tagname="img" src="/resources/assets/logo-white.svg" alt="F4" width="56" height="56" loading="lazy"></htmltag>
-</htmltag>
-<htmltag tagname="div" style="flex: 1 1 320px;">
-<htmltag tagname="div" style="font-size: 1.2em; font-weight: 600;">The public, stable reference for GD&T and how the F4 Application interprets it.</htmltag>
-<htmltag tagname="div" style="margin-top: 0.4em; color: var(--f4-text-muted);">Each topic pairs standard GD&T guidance with F4 validation behavior so you can move from definition to decision quickly.</htmltag>
-</htmltag>
-</htmltag>
-<htmltag tagname="div" style="margin-top: 0.9em; display: flex; gap: 8px; flex-wrap: wrap;">
-<htmltag tagname="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</htmltag>
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-</htmltag>
-</htmltag>
-{| style="width: 100%; border-collapse: separate; border-spacing: 12px;"
+== Quick links ==
+* [https://f4.dev/ F4 website]
+* [https://docs.f4.dev/ Documentation]
+* [https://download.f4.dev/ Downloads]
+== Start here ==
+{| class="f4-card-grid"
 |-
-| style="vertical-align: top; width: 33%;" |
+| class="f4-card" |
-<htmltag tagname="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/>
-<htmltag tagname="div" style="font-weight: 600;">GD&T Reference</htmltag>
+Standard definitions, symbols, and usage guidance.
-<htmltag tagname="div" style="margin-top: 0.4em; color: var(--f4-text-muted);">Standard definitions, symbols, and usage guidance.</htmltag>
+| class="f4-card" |
-</htmltag>
+'''[[:Category:F4 Behavior|F4 Behavior]]'''<br/>
-| style="vertical-align: top; width: 33%;" |
+Rules, checks, and decisions used by the F4 validator.
-<htmltag tagname="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" |
-<htmltag tagname="div" style="font-weight: 600;">F4 Behavior</htmltag>
+'''[[:Category:Glossary|Glossary and Examples]]'''<br/>
-<htmltag tagname="div" style="margin-top: 0.4em; color: var(--f4-text-muted);">Rules, checks, and decisions used by the F4 validator.</htmltag>
+Short definitions and worked applications.
-</htmltag>
-| style="vertical-align: top; width: 33%;" |
-<htmltag tagname="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);">
-<htmltag tagname="div" style="font-weight: 600;">Glossary and Examples</htmltag>
-<htmltag tagname="div" style="margin-top: 0.4em; color: var(--f4-text-muted);">Short definitions and worked applications.</htmltag>
-<htmltag tagname="div" style="margin-top: 0.6em; color: var(--f4-accent);">Browse glossary and examples</htmltag>
-</htmltag>
 |}
 == 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" |
-<htmltag tagname="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/>
-<htmltag tagname="div" style="font-weight: 600;">Form</htmltag>
+Straightness, flatness, circularity, cylindricity.
-<htmltag tagname="div" style="margin-top: 0.4em; color: var(--f4-text-muted);">Straightness, flatness, circularity, cylindricity.</htmltag>
+| class="f4-card" |
-</htmltag>
+'''[[:Category:Orientation|Orientation]]'''<br/>
-| style="vertical-align: top; width: 50%;" |
+Parallelism, perpendicularity, angularity.
-<htmltag tagname="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);">
-<htmltag tagname="div" style="font-weight: 600;">Orientation</htmltag>
-<htmltag tagname="div" style="margin-top: 0.4em; color: var(--f4-text-muted);">Parallelism, perpendicularity, angularity.</htmltag>
-</htmltag>
 |-
-| style="vertical-align: top; width: 50%;" |
+| class="f4-card" |
-<htmltag tagname="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/>
-<htmltag tagname="div" style="font-weight: 600;">Location</htmltag>
+Position, composite, MSS, concentricity, symmetry.
-<htmltag tagname="div" style="margin-top: 0.4em; color: var(--f4-text-muted);">Position, composite, MSS, concentricity, symmetry.</htmltag>
+| class="f4-card" |
-</htmltag>
+'''[[:Category:Profile|Profile]]'''<br/>
-| style="vertical-align: top; width: 50%;" |
+Line, surface, composite, MSS.
-<htmltag tagname="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);">
-<htmltag tagname="div" style="font-weight: 600;">Profile</htmltag>
-<htmltag tagname="div" style="margin-top: 0.4em; color: var(--f4-text-muted);">Line, surface, composite, MSS.</htmltag>
-</htmltag>
 |-
-| style="vertical-align: top; width: 50%;" |
+| class="f4-card" |
-<htmltag tagname="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/>
-<htmltag tagname="div" style="font-weight: 600;">Runout</htmltag>
+Circular and total runout.
-<htmltag tagname="div" style="margin-top: 0.4em; color: var(--f4-text-muted);">Circular and total runout.</htmltag>
+| class="f4-card" |
-</htmltag>
+'''Supporting rules'''
-| style="vertical-align: top; width: 50%;" |
+Related guidance for modifiers and datum systems.
-<htmltag tagname="div" style="background: var(--f4-bg-panel); border: 1px solid var(--f4-border); border-radius: 10px; padding: 0.9em;">
+* [[:Category:Modifiers|Modifiers]]
-<htmltag tagname="div" style="font-weight: 600;">Supporting rules</htmltag>
+* [[:Category:Datums|Datums]]
-<htmltag tagname="div" style="margin-top: 0.4em;">[[Category:Modifiers|Modifiers]] and [[Category:Datums|Datums]].</htmltag>
-</htmltag>
 |}
@@ Line 90: / Line 66: @@
 == Community ==
-{| style="width: 100%; border-collapse: separate; border-spacing: 12px;"
+{| class="f4-card-grid"
 |-
-| style="vertical-align: top; width: 50%;" |
+| class="f4-card" |
-<htmltag tagname="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/>
-<htmltag tagname="div" style="font-weight: 600;">Community forum</htmltag>
+Announcements, questions, feature requests, and showcases.
-<htmltag tagname="div" style="margin-top: 0.4em; color: var(--f4-text-muted);">Announcements, questions, feature requests, and showcases.</htmltag>
+| class="f4-card" |
-</htmltag>
+'''[[Special:UserBoard|Messages]]'''<br/>
-| style="vertical-align: top; width: 50%;" |
+Direct messages between contributors.
-<htmltag tagname="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);">
-<htmltag tagname="div" style="font-weight: 600;">Messages</htmltag>
-<htmltag tagname="div" style="margin-top: 0.4em; color: var(--f4-text-muted);">Direct messages between contributors.</htmltag>
-</htmltag>
 |}

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