a:custGeom (Custom Geometry)

Specifies a custom geometric shape defined by a series of paths and drawing instructions.

Parent elements

Child elements

Description

\:custGeom\ is the DrawingML element that defines a fully custom geometric shape. It is defined in ECMA-376 Part 1 §20.1.8.18.

Custom geometries provide complete control over shape definition via:

Guide values (\:gdLst) — Computed shape dimensions
Adjustment handles (\:ahLst) — User-adjustable parameters
Paths (\:pathLst) — Vector drawing commands
Connection points (\:cxnSpLst) — Where connectors attach

Custom geometries enable:

Arbitrary shape creation beyond preset library
Complex, precise geometry definitions
Shape customization via adjustment handles
Professional infographic design
Company-specific branded shapes
Specialized diagram elements

Custom geometries differ from:

Preset geometry (\:prstGeom) — Built-in shapes with preset IDs
Path geometry (\:path) — Single path (custom geometry uses multiple paths)

Attributes

Attribute	Type	Values	Description
(none)	-	-	\:custGeom\ has no attributes; all properties in child elements.

Content Model

\:custGeom\ structure:

a:avLst (optional, 0–1) — Adjustment value list for shape customization
a:gdLst (optional, 0–1) — Guide list with computed values
a:ahLst (optional, 0–1) — Adjustment handle list for UI manipulation
a:cxnSpLst (optional, 0–1) — Connection point list
a:pathLst (required, 1) — Path list defining shape outline

Child Elements Table

Element	Occurrence	Description
\:avLst\	0–1	Adjustment values for shape parameters
\:gdLst\	0–1	Guide entries with formulas for computed dimensions
\:ahLst\	0–1	Adjustment handles for interactive shape resizing
\:cxnSpLst\	0–1	Connection points where connectors attach
\:pathLst\	1	Paths that define shape outline/fill

Examples

Simple Custom Triangle

<a:custGeom>
  <a:avLst/>
  <a:gdLst/>
  <a:ahLst/>
  <a:cxnSpLst/>
  <a:pathLst>
    <a:path w="100000" h="100000">
      <a:moveTo><a:pt x="50000" y="0"/></a:moveTo>
      <a:lnTo><a:pt x="100000" y="100000"/></a:lnTo>
      <a:lnTo><a:pt x="0" y="100000"/></a:lnTo>
      <a:close/>
    </a:path>
  </a:pathLst>
</a:custGeom>

using DocumentFormat.OpenXml.Drawing;

var custGeom = new CustomGeometry();
custGeom.Append(new AdjustmentValueList());
custGeom.Append(new GuideList());
custGeom.Append(new AdjustmentHandleList());
custGeom.Append(new ConnectionShapeList());

var pathLst = new PathList();
var path = new Path { Width = 100000, Height = 100000 };

var moveTo = new MoveTo();
moveTo.Append(new Point { X = 50000, Y = 0 });
path.Append(moveTo);

var lnTo1 = new LineTo();
lnTo1.Append(new Point { X = 100000, Y = 100000 });
path.Append(lnTo1);

var lnTo2 = new LineTo();
lnTo2.Append(new Point { X = 0, Y = 100000 });
path.Append(lnTo2);

path.Append(new CloseShapePath());
pathLst.Append(path);
custGeom.Append(pathLst);

Custom Shape with Adjustment Handles

<a:custGeom>
  <a:avLst>
    <a:gd name="adj" val="50000"/>
  </a:avLst>
  <a:gdLst>
    <a:gd name="x1" fmla="*/ adj 100000 100000"/>
  </a:gdLst>
  <a:ahLst>
    <a:ahXY n="adj" x="x1" y="50000"/>
  </a:ahLst>
  <a:cxnSpLst/>
  <a:pathLst>
    <a:path w="100000" h="100000">
      <a:moveTo><a:pt x="0" y="50000"/></a:moveTo>
      <a:lnTo><a:pt x="x1" y="0"/></a:lnTo>
      <a:lnTo><a:pt x="100000" y="50000"/></a:lnTo>
      <a:lnTo><a:pt x="x1" y="100000"/></a:lnTo>
      <a:close/>
    </a:path>
  </a:pathLst>
</a:custGeom>

var custGeom = new CustomGeometry();

var avLst = new AdjustmentValueList();
var adjGd = new GuideEntry { Name = "adj", Formula = "50000" };
avLst.Append(adjGd);
custGeom.Append(avLst);

var gdLst = new GuideList();
var guideGd = new GuideEntry 
{ 
  Name = "x1", 
  Formula = "*/ adj 100000 100000" 
};
gdLst.Append(guideGd);
custGeom.Append(gdLst);

var ahLst = new AdjustmentHandleList();
var ah = new AdjustmentHandle { PositionH = "x1", PositionV = "50000" };
ah.Append(new GuideRef { Name = "adj" });
ahLst.Append(ah);
custGeom.Append(ahLst);

custGeom.Append(new ConnectionShapeList());

var pathLst = new PathList();
var path = new Path { Width = 100000, Height = 100000 };
// Add path drawing commands...
pathLst.Append(path);
custGeom.Append(pathLst);

Custom Callout Shape

<a:custGeom>
  <a:avLst/>
  <a:gdLst/>
  <a:ahLst/>
  <a:cxnSpLst>
    <a:cxnSp x="50000" y="100000"/>
    <a:cxnSp x="0" y="50000"/>
  </a:cxnSpLst>
  <a:pathLst>
    <a:path w="100000" h="100000">
      <a:moveTo><a:pt x="0" y="0"/></a:moveTo>
      <a:lnTo><a:pt x="100000" y="0"/></a:lnTo>
      <a:lnTo><a:pt x="100000" y="80000"/></a:lnTo>
      <a:lnTo><a:pt x="50000" y="100000"/></a:lnTo>
      <a:lnTo><a:pt x="100000" y="80000"/></a:lnTo>
      <a:lnTo><a:pt x="100000" y="100000"/></a:lnTo>
      <a:lnTo><a:pt x="0" y="100000"/></a:lnTo>
      <a:close/>
    </a:path>
  </a:pathLst>
</a:custGeom>

var custGeom = new CustomGeometry();
custGeom.Append(new AdjustmentValueList());
custGeom.Append(new GuideList());
custGeom.Append(new AdjustmentHandleList());

var cxnSpLst = new ConnectionShapeList();
var cxnSp1 = new ConnectionShape { X = 50000, Y = 100000 };
var cxnSp2 = new ConnectionShape { X = 0, Y = 50000 };
cxnSpLst.Append(cxnSp1);
cxnSpLst.Append(cxnSp2);
custGeom.Append(cxnSpLst);

var pathLst = new PathList();
var path = new Path { Width = 100000, Height = 100000 };
// Add callout shape path commands...
pathLst.Append(path);
custGeom.Append(pathLst);

Shape with Multiple Paths (Composite)

<a:custGeom>
  <a:avLst/>
  <a:gdLst/>
  <a:ahLst/>
  <a:cxnSpLst/>
  <a:pathLst>
    <a:path w="100000" h="100000">
      <a:moveTo><a:pt x="0" y="0"/></a:moveTo>
      <a:lnTo><a:pt x="100000" y="0"/></a:lnTo>
      <a:lnTo><a:pt x="100000" y="100000"/></a:lnTo>
      <a:lnTo><a:pt x="0" y="100000"/></a:lnTo>
      <a:close/>
    </a:path>
    <a:path w="100000" h="100000">
      <a:moveTo><a:pt x="25000" y="25000"/></a:moveTo>
      <a:lnTo><a:pt x="75000" y="25000"/></a:lnTo>
      <a:lnTo><a:pt x="75000" y="75000"/></a:lnTo>
      <a:lnTo><a:pt x="25000" y="75000"/></a:lnTo>
      <a:close/>
    </a:path>
  </a:pathLst>
</a:custGeom>

var custGeom = new CustomGeometry();
custGeom.Append(new AdjustmentValueList());
custGeom.Append(new GuideList());
custGeom.Append(new AdjustmentHandleList());
custGeom.Append(new ConnectionShapeList());

var pathLst = new PathList();

// Outer rectangle
var path1 = new Path { Width = 100000, Height = 100000 };
// Add outer path commands...
pathLst.Append(path1);

// Inner rectangle (hole)
var path2 = new Path { Width = 100000, Height = 100000 };
// Add inner path commands...
pathLst.Append(path2);

custGeom.Append(pathLst);

Shape with Guide Formulas

<a:custGeom>
  <a:avLst>
    <a:gd name="w" val="100000"/>
    <a:gd name="h" val="100000"/>
  </a:avLst>
  <a:gdLst>
    <a:gd name="halfW" fmla="*/ w 1 2"/>
    <a:gd name="halfH" fmla="*/ h 1 2"/>
  </a:gdLst>
  <a:ahLst/>
  <a:cxnSpLst/>
  <a:pathLst>
    <a:path w="w" h="h">
      <a:moveTo><a:pt x="halfW" y="0"/></a:moveTo>
      <a:lnTo><a:pt x="w" y="halfH"/></a:lnTo>
      <a:lnTo><a:pt x="halfW" y="h"/></a:lnTo>
      <a:lnTo><a:pt x="0" y="halfH"/></a:lnTo>
      <a:close/>
    </a:path>
  </a:pathLst>
</a:custGeom>

var custGeom = new CustomGeometry();

var avLst = new AdjustmentValueList();
avLst.Append(new GuideEntry { Name = "w", Formula = "100000" });
avLst.Append(new GuideEntry { Name = "h", Formula = "100000" });
custGeom.Append(avLst);

var gdLst = new GuideList();
gdLst.Append(new GuideEntry { Name = "halfW", Formula = "*/ w 1 2" });
gdLst.Append(new GuideEntry { Name = "halfH", Formula = "*/ h 1 2" });
custGeom.Append(gdLst);

custGeom.Append(new AdjustmentHandleList());
custGeom.Append(new ConnectionShapeList());

var pathLst = new PathList();
var path = new Path { Width = "w", Height = "h" };
// Add diamond path...
pathLst.Append(path);
custGeom.Append(pathLst);

Path Drawing Commands

Custom geometry paths use these commands:

Command	Element	Purpose
Move To	\:moveTo\	Set starting point (lift pen)
Line To	\:lnTo\	Draw line to point
Arc To	\:arcTo\	Draw arc to point
Quadratic Bezier	\:quadBezTo\	Draw quadratic curve
Cubic Bezier	\:cubicBezTo\	Draw cubic curve
Close	\:close\	Close shape path

Guide Formulas

Common guide formula patterns:

Formula	Purpose	Example
*/ a b c\	Multiply and divide	*/ 50000 w 100000\ (scale)
+- a b c\	Add/subtract	+- w 10000 5000\ (offset)
+/ a b c\	Add and divide	+/ w h 2\ (average)
\if a b c\	Conditional	\if cond val1 val2\
\bs a\	Absolute value	\bs adj\
\min a b\	Minimum	\min w h\
\max a b\	Maximum	\max w h\
\mod a b c\	Modulo	\mod val divisor remainder\

Adjustment Handles

Handles allow user interaction:

Handle Type	Purpose	Properties
\:ahXY\	2D point	x, y coordinates
\:ahPolar\	Polar point	radius, angle

Handles reference guide values via \:gd\ child elements.

Connection Points

Connection points (\:cxnSp) define where connectors attach:

xml <a:cxnSpLst> <a:cxnSp x="50000" y="0"/> <a:cxnSp x="100000" y="50000"/> <a:cxnSp x="50000" y="100000"/> <a:cxnSp x="0" y="50000"/> </a:cxnSpLst>

Typically placed at cardinal/ordinal points of shape boundary.

Common Patterns

Simple Diamond

xml <a:pathLst> <a:path w="100000" h="100000"> <a:moveTo><a:pt x="50000" y="0"/></a:moveTo> <a:lnTo><a:pt x="100000" y="50000"/></a:lnTo> <a:lnTo><a:pt x="50000" y="100000"/></a:lnTo> <a:lnTo><a:pt x="0" y="50000"/></a:lnTo> <a:close/> </a:path> </a:pathLst>

Hexagon with Center

xml <a:pathLst> <a:path w="100000" h="100000">  <a:moveTo><a:pt x="50000" y="0"/></a:moveTo>  </a:path> <a:path w="100000" h="100000">  <a:moveTo><a:pt x="40000" y="40000"/></a:moveTo>  </a:path> </a:pathLst>

Notes

Element Characteristics

Fully custom: Complete control over shape geometry
Path-based: Defined via drawing commands (moveTo, lineTo, etc.)
Parameterized: Adjustable via adjustment values and handles
Guides: Support computed dimensions via formulas
Connectable: Optional connection points for diagram connectors

Complexity vs Presets

Preset: Simple ID, fast rendering, limited customization
Custom: Full control, complex definition, slower rendering

Rendering

Fill: Applied to enclosed area within paths
Outline: Applied to path strokes
Transformation: Applied to entire geometry
Performance: More complex than preset geometry

Best Practices

Use preset geometry when available (simpler, faster)
Custom geometry for unique/branded shapes
Test geometry rendering across Office versions
Use guides for proportional scaling
Document shape parameters and adjustments
Consider performance impact with complex paths
Provide adjustment handles for user customization

Compatibility

Office 2007 and later
All custom geometry commands consistently supported
Complex geometries may render differently in older versions
PDF export preserves custom geometry rendering

File Size

Simple custom geometry: Similar to preset
Complex multi-path geometry: Larger file size
Guides and formulas: Minimal size impact
Optimization: Remove redundant guides and paths