Revision as of 18:23, 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 =
-[[File:F4_Logo_White.svg|56px|alt=F4]]
+[[File:F4_Logo_White.svg|frameless|link=Main_Page|alt=F4|class=f4-logo]]
 ''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.
@@ Line 14: / Line 14: @@
 {| class="f4-card-grid"
 |-
-| [[Category:GDT Reference|<span class="f4-card-link"><span class="f4-card-title">GD&T Reference</span><span class="f4-card-desc">Standard definitions, symbols, and usage guidance.</span></span>]]
+| class="f4-card" |
-| [[Category:F4 Behavior|<span class="f4-card-link"><span class="f4-card-title">F4 Behavior</span><span class="f4-card-desc">Rules, checks, and decisions used by the F4 validator.</span></span>]]
+'''[[:Category:GDT Reference|GD&T Reference]]'''<br/>
-| [[Category:Glossary|<span class="f4-card-link"><span class="f4-card-title">Glossary and Examples</span><span class="f4-card-desc">Short definitions and worked applications.</span></span>]]
+Standard definitions, symbols, and usage guidance.
+| class="f4-card" |
+'''[[:Category:F4 Behavior|F4 Behavior]]'''<br/>
+Rules, checks, and decisions used by the F4 validator.
+| class="f4-card" |
+'''[[:Category:Glossary|Glossary and Examples]]'''<br/>
+Short definitions and worked applications.
 |}
@@ Line 22: / Line 28: @@
 {| class="f4-card-grid"
 |-
-| [[Category:Form|<span class="f4-card-link"><span class="f4-card-title">Form</span><span class="f4-card-desc">Straightness, flatness, circularity, cylindricity.</span></span>]]
+| class="f4-card" |
-| [[Category:Orientation|<span class="f4-card-link"><span class="f4-card-title">Orientation</span><span class="f4-card-desc">Parallelism, perpendicularity, angularity.</span></span>]]
+'''[[:Category:Form|Form]]'''<br/>
+Straightness, flatness, circularity, cylindricity.
+| class="f4-card" |
+'''[[:Category:Orientation|Orientation]]'''<br/>
+Parallelism, perpendicularity, angularity.
 |-
-| [[Category:Location|<span class="f4-card-link"><span class="f4-card-title">Location</span><span class="f4-card-desc">Position, composite, MSS, concentricity, symmetry.</span></span>]]
+| class="f4-card" |
-| [[Category:Profile|<span class="f4-card-link"><span class="f4-card-title">Profile</span><span class="f4-card-desc">Line, surface, composite, MSS.</span></span>]]
+'''[[:Category:Location|Location]]'''<br/>
+Position, composite, MSS, concentricity, symmetry.
+| class="f4-card" |
+'''[[:Category:Profile|Profile]]'''<br/>
+Line, surface, composite, MSS.
 |-
-| [[Category:Runout|<span class="f4-card-link"><span class="f4-card-title">Runout</span><span class="f4-card-desc">Circular and total runout.</span></span>]]
+| class="f4-card" |
-| <span class="f4-card-link"><span class="f4-card-title">Supporting rules</span><span class="f4-card-desc">Related guidance for modifiers and datum systems.</span><span class="f4-card-links">[[Category:Modifiers|<span class="f4-pill">Modifiers</span>]] [[Category:Datums|<span class="f4-pill">Datums</span>]]</span></span>
+'''[[:Category:Runout|Runout]]'''<br/>
+Circular and total runout.
+| class="f4-card" |
+'''Supporting rules'''
+Related guidance for modifiers and datum systems.
+* [[:Category:Modifiers|Modifiers]]
+* [[:Category:Datums|Datums]]
 |}
@@ Line 48: / Line 68: @@
 {| class="f4-card-grid"
 |-
-| [[Forum:Start|<span class="f4-card-link"><span class="f4-card-title">Community forum</span><span class="f4-card-desc">Announcements, questions, feature requests, and showcases.</span></span>]]
+| class="f4-card" |
-| [[Special:UserBoard|<span class="f4-card-link"><span class="f4-card-title">Messages</span><span class="f4-card-desc">Direct messages between contributors.</span></span>]]
+'''[[Forum:Start|Community forum]]'''<br/>
+Announcements, questions, feature requests, and showcases.
+| class="f4-card" |
+'''[[Special:UserBoard|Messages]]'''<br/>
+Direct messages between contributors.
 |}

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