SHX & SHP File Guide — AutoCAD 2024

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The Big Picture

AutoCAD uses two file types to handle fonts and custom symbols — .SHP is the human-readable source file you write, and .SHX is the compiled binary that AutoCAD actually loads. Think of .SHP as source code and .SHX as the program that runs from it.

📝

Text Editor

Notepad / VS Code

→

📄

.SHP File

Human-readable source

→

⚙️

COMPILE

AutoCAD command

→

🔒

.SHX File

Binary — AutoCAD reads this

→

🖊️

AutoCAD

Fonts, symbols, linetypes

📄 .SHP — Shape Source File

Plain text file — open with any text editor
Written by you (the drafter or programmer)
Contains shape definitions as numeric codes
One .SHP can define many shapes or an entire font
AutoCAD cannot use this file directly
Must be compiled into .SHX first
Safe to edit and re-compile as often as needed
Small file size — just text characters

🔒 .SHX — Compiled Shape File

Binary file — not human-readable
Produced by AutoCAD's COMPILE command
The file AutoCAD actually loads and uses
Used for text fonts in text styles and dimensions
Used for custom symbols in complex linetypes
Must live in AutoCAD's Support File Search Path
Faster to load than TrueType fonts in complex drawings
No source code inside — can't be "uncompiled"

The Three Types of .SHX Files

Not all .SHX files do the same thing. There are three distinct types and they serve very different purposes.

Type	What It Does	How AutoCAD Uses It	Examples
Font .SHX Font	Defines a complete alphabet — every letter, number, and symbol as vector strokes. These are the fonts you pick in the Text Style dialog.	Text styles, DTEXT, MTEXT, Dimension text, Leaders, Attributes	romans.shx, txt.shx, isocp.shx
Shape .SHX Shape	Defines individual geometric symbols — not letters, but custom shapes like a gas bubble, electrical symbol, or north arrow. Each shape has a number.	Complex linetypes (embedded shapes), the SHAPE command to insert symbols	ltypeshp.shx, esri.shx, custom utility symbols
Bigfont .SHX BigFont	Extended font for double-byte character sets — Japanese, Korean, Chinese, and other languages that have thousands of characters.	Text styles where a second "Bigfont" file is specified alongside a regular font	bigfont.shx, chineset.shx, extfont.shx

Why AutoCAD Uses .SHX Instead of TrueType Fonts

Speed & Simplicity: .SHX fonts are pure vector strokes — they draw extremely fast even in dense drawings with thousands of text objects. TrueType fonts (like Arial or Calibri) look better when printed but are more complex to render, can slow down large drawings, and sometimes cause issues with hatching, mirroring, or old plotter drivers.

The engineering tradition: Most engineering standards (ASME, ISO, military specs) were developed when only .SHX-style fonts existed. Many companies still require romans.shx or isocp.shx by standard. If your company has a CAD standard, check which font is required before changing it.

⚠ Key rule: The .SHX file must be present whenever someone opens a drawing that uses it. If the file is missing, AutoCAD substitutes a different font, which can completely change how text looks and how much space it takes up — potentially ruining carefully placed labels and title blocks.

Default AutoCAD Font Folder

AutoCAD ships with dozens of built-in .SHX fonts. They all live in the Fonts subfolder inside the AutoCAD installation directory. These paths vary by version:

AutoCAD Version	Default SHX Font Path
AutoCAD 2024	C:\Program Files\Autodesk\AutoCAD 2024\Fonts\
AutoCAD 2023	C:\Program Files\Autodesk\AutoCAD 2023\Fonts\
AutoCAD 2022	C:\Program Files\Autodesk\AutoCAD 2022\Fonts\
AutoCAD LT 2024	C:\Program Files\Autodesk\AutoCAD LT 2024\Fonts\
User profile (roaming)	C:\Users\[YourName]\AppData\Roaming\Autodesk\AutoCAD 2024\R24.3\enu\Support\

💡 Quick way to find it: Type OPTIONS in AutoCAD → click the Files tab → expand Support File Search Path. Every folder listed there is a place AutoCAD will look for .SHX files.

Adding Your Own SHX Search Path

When you create or receive custom .SHX files, you need to tell AutoCAD where to find them. Never copy custom files into the Autodesk installation folder — that's reserved for Autodesk. Use the Support File Search Path instead.

Type OPTIONS at the command line and press Enter (or go to Application Menu → Options)
Click the Files tab at the top of the Options dialog
Expand Support File Search Path by clicking the + sign next to it
Click the Add… button on the right side
Click Browse… and navigate to the folder where your custom .SHX files are stored (e.g., C:\CompanyStandards\Fonts\)
Click OK to close the Options dialog. AutoCAD will now find your custom .SHX files every time a drawing uses them.

⚠ Network tip: If your office uses a network server for CAD standards, point this path to the server (e.g., \\server\CADStandards\Fonts\). Everyone who maps to that path will automatically have access to all company .SHX files.

How to See Which .SHX a Drawing Uses

A drawing can use many different .SHX fonts — one per text style. Here's how to check:

Method	What to Do	What You See
STYLE	Type STYLE at the command line, press Enter	Text Style Manager — every style listed shows its font file name in the "Font Name" column
-STYLE	Type -STYLE (with dash) at command line	Command-line version — lists all styles and prompts for changes
Properties Panel	Select any text object → open Properties panel (Ctrl+1)	Shows the text style name — cross-reference with the STYLE command
AUDIT report	Type AUDIT → Yes to fix errors	If a font file is missing, AutoCAD reports it in the audit log

What Happens When a .SHX File is Missing

When you open a drawing and AutoCAD cannot find a required .SHX file, it shows the "Specify Font for Style" dialog. This lets you choose a substitute font to use instead. Whatever you choose only affects the current session — it does not permanently change the drawing's text style definition. The style still "wants" the original .SHX file.

If you regularly open drawings with the same missing font, the best fix is to obtain the actual .SHX file and place it in a folder that's in your Support File Search Path. The second-best fix is to redefine the text style using a font you do have (type STYLE, select the style, change the font).

Symptom	Likely Cause	Fix
"Specify Font for Style" dialog on open	Required .SHX is missing from search path	Get the .SHX and add its folder to Options → Files → Support File Search Path
Text looks wrong / different size after opening	AutoCAD substituted a different font automatically (simplex.shx is the common substitute)	Same as above — provide the original .SHX
Linetype looks like a plain dashed line instead of having symbols	The shape .SHX used by that linetype is missing	Find or recreate the shape .SHX file (commonly ltypeshp.shx)
Question marks or boxes where characters should be	Wrong font file selected, or BigFont missing for international characters	Correct the font in the text style and add the BigFont if needed

AutoCAD's Built-In SHX Font Library

AutoCAD ships with around 90 .SHX font files. Most practicing drafters use only a handful. Here are the ones you'll actually encounter, grouped by category.

★ The Most-Used Fonts (Know These First)

txt.shx

Font

The simplest AutoCAD font. Single-stroke, bare-minimum. Fast, small file size. Very boxy/basic appearance. Often used for rough work or where speed matters more than looks.

Best for: Internal notes, scratch layers, situations requiring smallest possible file size

romans.shx

Font

Roman Simplex — single-stroke Roman letterforms. Clean, professional appearance. The most popular SHX font in engineering. Slightly wider than txt.shx so text takes slightly more space.

Best for: General engineering drawings, title blocks, notes. The default choice for most drafters

isocp.shx

Font

ISO Cyrillic Proportional — conforms to ISO 3098 drafting standard. Slightly slanted letterforms. Required on many international and government engineering projects.

Best for: Drawings that must meet ISO standards; international project submissions

isoct.shx

Font

ISO Title block font. Upright version of isocp. Used for title block text on ISO-standard drawings. Slightly more compressed than romans.

Best for: Title blocks on ISO drawings, headings that need to look structured

monotxt.shx

Font

Monospaced version of txt.shx. Every character takes exactly the same width — like a typewriter. Useful for data tables and schedules where columns must align perfectly.

Best for: Tables, schedules, BOMs where column alignment is critical

simplex.shx

Font

AutoCAD's default substitute font — what AutoCAD uses when a drawing references a missing .SHX. If your text changes appearance mysteriously, this is likely the culprit. Single-stroke, clean, readable.

Best for: Avoid using it directly — it's a fallback. Use romans.shx or isocp.shx instead

Complete Built-In Font Reference

File Name	Full Name	Type	Notes
txt.shx	Standard (Text)	Font	Simplest, fastest. Basic blocky letters.
simplex.shx	Simplex Roman	Font	AutoCAD's missing-font substitute. Simple single-stroke.
romans.shx	Roman Simplex	Font	Most popular engineering font. Clean single-stroke.
romand.shx	Roman Duplex	Font	Double-stroke version of romans. Slightly thicker.
romanc.shx	Roman Complex	Font	Multi-stroke Roman. More decorative, heavier.
romant.shx	Roman Triplex	Font	Triple-stroke Roman. Bold appearance.
italics.shx	Italic Simplex	Font	Slanted single-stroke. Italic variant of romans.
italicc.shx	Italic Complex	Font	Multi-stroke italic. More decorative.
italict.shx	Italic Triplex	Font	Triple-stroke italic. Bold slanted text.
scripts.shx	Script Simplex	Font	Handwriting style. Rarely used in engineering.
scriptc.shx	Script Complex	Font	More detailed handwriting style.
gothice.shx	Gothic English	Font	Old English/Blackletter style. Decorative only.
gothicg.shx	Gothic German	Font	German Blackletter variant.
gothici.shx	Gothic Italian	Font	Italian Blackletter variant.
greeks.shx	Greek Simplex	Font	Greek alphabet, single-stroke. For math/engineering symbols.
greekc.shx	Greek Complex	Font	Greek alphabet, multi-stroke.
symath.shx	Math Symbols	Font	Mathematical symbols (∑, ∫, √, etc.)
symeteo.shx	Meteorological Symbols	Font	Weather map symbols.
symap.shx	Map Symbols	Font	Cartography / map-making symbols.
monotxt.shx	Monospace Text	Font	Fixed-width. Every character same width. Table alignment.
isocp.shx	ISO Cyrillic Proportional	Font	ISO 3098 compliant. Slanted. International standard.
isocp2.shx	ISO Cyrillic Proportional 2	Font	Alternate ISO variant.
isocp3.shx	ISO Cyrillic Proportional 3	Font	Third ISO variant.
isoct.shx	ISO Title Block	Font	Upright ISO standard. Title blocks.
isoct2.shx	ISO Title Block 2	Font	Alternate ISO title variant.
isoct3.shx	ISO Title Block 3	Font	Third ISO title variant.
ltypeshp.shx	Linetype Shapes	Shape	Ships with AutoCAD. Provides shapes for complex linetypes (gas, electric, fence, etc.)
gdt.shx	GD&T Symbols	Shape	Geometric Dimensioning & Tolerancing symbols. Used in mechanical drawings.
bigfont.shx	Big Font (Asian)	BigFont	Extended double-byte character support. For Asian language text.

Choosing the right font for engineering: For utility and electrical engineering (your field), romans.shx is the standard go-to for most annotations and notes. isocp.shx is required if your company follows ISO 3098. monotxt.shx is ideal for conductor/equipment schedules where columns must line up. Use txt.shx only for internal markup layers you don't plan to print.

How .SHP Files Work — The Basics

A .SHP file is a plain text file that describes shapes using a special coding system. Each shape is a numbered definition — a sequence of codes that tell AutoCAD where to move the "pen," whether the pen is up or down, and what direction to draw in.

The analogy: Think of a shape definition like giving directions to someone walking on a grid — "walk 3 steps right, turn and walk 2 steps up, pick up the pen, walk 2 steps right, put the pen down, walk 1 step diagonally." AutoCAD follows your coded directions to draw the shape.

.SHP File Structure

Every .SHP file follows this pattern. Each shape starts with a header line and is followed by definition codes:

; Lines starting with ; are comments — AutoCAD ignores them
; ──────────────────────────────────────────────────────────
; .SHP File Structure
; ──────────────────────────────────────────────────────────

; The header line format:
*shapeno,defbytes,shapename

; *shapeno  = unique number 1–255 (or 0 for the file header itself)
; defbytes  = total number of bytes in the definition that follows
; shapename = name used to call this shape (all UPPERCASE)

; Example: shape #1 named BOX, 7 definition bytes
*1,7,BOX
010,020,012,02C,01A,008,0

; The last code in every shape definition must be 0 (end of shape)

Shape Definition Codes — Complete Reference

These are the hexadecimal codes you place in a shape definition line. They control pen state, movement direction, and special drawing operations.

Core Control Codes

Code (hex)	Decimal	Name	What It Does
000	0	End Shape	Required last code. Marks the end of the shape definition.
001	1	Pen Down	Put the pen down — subsequent moves will draw lines.
002	2	Pen Up	Lift the pen — subsequent moves will not draw.
003,n	3,n	Divide Scale	Divide the current drawing scale by n. Makes all subsequent moves smaller.
004,n	4,n	Multiply Scale	Multiply the current scale by n. Makes all subsequent moves larger.
005	5	Push Position	Save the current position to a stack (like a bookmark).
006	6	Pop Position	Return to the saved position (undo the push).
007,n	7,n	Draw Subshape	Draw another shape n from this file at the current position.
008,(x,y)	8	XY Displacement	Move by exact X,Y amount (signed bytes from -128 to +127).
009,(x,y,...),(0,0)	9	Multiple XY	Chain of XY displacements, terminated by 0,0.
00A,r,sc	10	Octant Arc	Draw an arc. r=radius, sc=start/end octants encoded as a single byte.
00B,r,sc,h	11	Fractional Arc	Arc with fractional start/end positions for more precision.
00C,x,y,r	12	Arc via Displacement	Draw an arc using displacement and radius. Easier for smooth curves.
00D	13	Multiple Arcs	Chain of arc definitions.
00E	14	Next Command on Flag	Process next code only if drawing with a vertical text flag.

Direction Codes (Hex 010–01F) — The 16 Compass Directions

These are the most common codes in any .SHP file. Each moves the pen one unit in a specific direction at a 22.5° increment. The first digit (0) means "short move" (half the unit size).

Code	Direction	Degrees	Code	Direction	Degrees
010	Right (East)	0°	018	Left (West)	180°
011	Right + slightly up	22.5°	019	Left + slightly down	202.5°
012	Right + Up (diagonal)	45°	01A	Left + Down (diagonal)	225°
013	Slightly right + Up	67.5°	01B	Slightly left + Down	247.5°
014	Up (North)	90°	01C	Down (South)	270°
015	Slightly left + Up	112.5°	01D	Slightly right + Down	292.5°
016	Left + Up (diagonal)	135°	01E	Right + Down (diagonal)	315°
017	Mostly left + slightly up	157.5°	01F	Mostly right + slightly down	337.5°

A Real Example — Reading a Simple Shape

; Shape #1: A simple cross / plus sign (+)
; Header: shape number, byte count, name
*1,13,CROSS
; Pen up, go to start position (left side of cross)
002,   ; Pen UP
018,   ; Move LEFT 1 unit (to start at left)
001,   ; Pen DOWN
010,   ; Draw RIGHT 1 unit (left half of horizontal)
010,   ; Draw RIGHT 1 unit (right half of horizontal)
002,   ; Pen UP
018,   ; Move LEFT 1 unit (back to center)
01C,   ; Move DOWN 1 unit (to start of vertical)
001,   ; Pen DOWN
014,   ; Draw UP 1 unit (bottom half of vertical)
014,   ; Draw UP 1 unit (top half of vertical)
002,   ; Pen UP
000    ; End shape (REQUIRED)

💡 Tip: The "byte count" in the header must exactly match the number of codes that follow (including the final 0). If it's wrong, AutoCAD will reject the shape on compile. Count every code on the definition line, including the terminating 0.

What You Need

✅ Required (Free)

Any text editor — Notepad (Windows), TextEdit (Mac), VS Code, Notepad++
AutoCAD — any version with the COMPILE command (all commercial versions)
That's it. No special software required to write a .SHP file.

🛠 Optional (Paid / Specialized)

VS Code with AutoCAD extensions — syntax highlighting for .SHP
Notepad++ — free, good for larger .SHP projects
Scanahand — draw letters by hand, converts to font (then save as SHX)
CAD-format font editors — rare, mostly legacy tools

Step-by-Step: Create a Custom Shape

We'll create a simple electrical ground symbol — three horizontal lines getting shorter, like a common electrical earth ground. This is exactly the kind of shape you'd embed in a linetype for electrical utility drawings.

Step 1 — Plan Your Shape on Paper First

Before writing a single code, sketch your shape on graph paper. Label the start point (where AutoCAD will be when it begins drawing). Mark each point as UP (no line) or DOWN (draw line). Identify the direction from each point to the next. This planning step saves enormous debugging time.

Step 2 — Write the .SHP File

Open Notepad and type the following. Save it as .shp — make sure Notepad isn't adding .txt to the end (use "All Files" in the Save dialog).

; =======================================================
; File: my_electric_shapes.shp
; Author: [Your Name]
; Description: Custom electrical shapes for utility drawings
; =======================================================

; FILE HEADER: shape 0 defines the file itself
; Format: *0,bytes,filename
*0,4,MY_ELECTRIC_SHAPES
0

; -------------------------------------------------------
; SHAPE 1: GROUND symbol (electrical earth ground)
; Draws a vertical stem then three decreasing horizontal bars
; -------------------------------------------------------
*1,23,GROUND
001,  ; Pen DOWN
01C,  ; Move DOWN 1 (draw vertical stem down)
002,  ; Pen UP
018,018,  ; Move LEFT 2 (to start of widest bar)
001,  ; Pen DOWN
010,010,010,010,  ; Draw RIGHT 4 (widest bar)
002,  ; Pen UP
018,018,018,  ; Back LEFT 3, then move to next bar
01C,  ; Move DOWN 1
010,  ; Right 1 to indent
001,  ; Pen DOWN
010,010,  ; Draw RIGHT 2 (middle bar)
002,  ; Pen UP
018,018,018,  ; Back LEFT 3
01C,  ; Move DOWN 1
010,010,  ; Right 2 to indent
001,  ; Pen DOWN
010,  ; Draw RIGHT 1 (narrowest bar)
002,  ; Pen UP
000   ; End shape

; -------------------------------------------------------
; SHAPE 2: PHASE marker (small triangle pointing right)
; -------------------------------------------------------
*2,9,PHASE
001,  ; Pen DOWN
012,  ; Draw UP-RIGHT diagonal
01C,  ; Draw DOWN
016,  ; Draw UP-LEFT diagonal (closes the triangle)
002,  ; Pen UP
010,  ; Move right (exit position)
000   ; End shape

Step 3 — Compile It in AutoCAD

Open AutoCAD (the file you're working in doesn't matter for this step)
Type COMPILE at the command line and press Enter
A file browser appears. Navigate to where you saved your .SHP file and select it. Click OK.
AutoCAD compiles the file. If successful, you'll see: Compilation successful. Output file: my_electric_shapes.shx in the command line. The .SHX file is created in the same folder as your .SHP file.
If there are errors, AutoCAD reports which line failed. Common errors: wrong byte count, missing final 0, invalid code. Fix in your text editor and re-compile.
Copy the resulting .SHX file (not the .SHP) to a folder in your Support File Search Path. Or add the folder to OPTIONS → Files → Support File Search Path.

⚠ The byte count must be exact. The number after the shape name in the header (*1,23,GROUND) must exactly equal the number of codes that follow. Count every code including the final 0. If you add or remove a code and forget to update this number, COMPILE will fail with "Invalid shape definition."

Step 4 — Load and Use Your Shape

What You Want	Command	How
Insert the shape as a symbol in a drawing	SHAPE	Type SHAPE → enter the shape name (e.g., GROUND) → specify location, height, rotation
Use in a text style (if it's a font)	STYLE	Create/edit a text style → type the .SHX filename in the Font Name field
Use in a custom linetype	-LINETYPE	Reference the shape by name in a .LIN file definition (see Linetype tab)
List all available shapes in a loaded file	LOAD	Load the .SHX first, then the SHAPE command shows available shape names

Creating a Custom Font (.SHP with Characters)

Creating a full custom font is more involved — you need to define every character in your alphabet (typically shapes 032 through 0FF for ASCII). Here's the structure:

; Custom font file — defines text characters as shapes
; Font files must have shape 0 as the font description line

; Font header (shape 0):
; Format: *0,4,fontname
; Followed by: above,below,modes,0
;   above = height of capital letters (in shape units)
;   below = depth below baseline for descenders (g, y, p)
;   modes = 0 for horizontal text, 2 for dual-orientation
*0,4,MYFONT
6,2,2,0

; Shape 032 (hex 020) = SPACE character
; Every font needs a space — just move right without drawing
*032,3,SPACE
002,  ; Pen UP (no drawing)
010,  ; Move right (space width)
000   ; End

; Shape 065 (hex 041) = letter "A"
; Drawing the letter A:
*065,14,UCA
002,  ; Pen UP
01C,  ; Position at bottom-left
001,  ; Pen DOWN
013,013,013,  ; Left stroke going up-right
01F,01F,01F,  ; Right stroke going down-right
002,  ; Pen UP
018,018,  ; Move back left to midpoint
014,  ; Move up to crossbar height
001,  ; Pen DOWN
010,  ; Draw crossbar right
002,  ; Pen UP
000   ; End

; Continue defining shapes for: B=066, C=067 ... Z=090
; then lowercase: a=097 ... z=122
; then numbers: 0=048 ... 9=057
; then special chars as needed

💡 Practical advice: Writing a complete custom font from scratch is a multi-day project. For most utility drafters, the better approach is to modify an existing font — copy the relevant .SHP source (many are available on Autodesk forums and CAD communities), change what you need, and recompile. Only create a font from scratch when your company needs a proprietary branded typeface.

Shape .SHX Files and Complex Linetypes

This is where .SHX files become incredibly powerful for utility drafters. AutoCAD's complex linetypes can embed custom shapes directly into the line pattern — so a gas main line can show actual gas bubble symbols, or an electrical line can show phase markers. The shapes come from a Shape .SHX file.

The classic example: AutoCAD ships with ltypeshp.shx which contains shapes like TRACK, BATTING, ZIGZAG, HOT_WATER_SUPPLY, and many utility/architectural symbols. These shapes are what power complex linetypes in ltypeshp.lin. You can add your own shapes to extend this file, or create a separate .SHX for your company's custom linetypes.

How Shape References Work in .LIN Files

In a .LIN file, you embed a shape using this syntax inside the linetype definition:

; .LIN file syntax for shape-based complex linetypes
; ─────────────────────────────────────────────────────────────
; Basic format:
*LINETYPE_NAME,Description text
A,gap,[SHAPENAME,shxfile.shx,S=scale,R=rotation,X=xoffset,Y=yoffset],gap

; ─────────────────────────────────────────────────────────────
; Shape element parameters:
;   SHAPENAME  = name of the shape (matches what's in the .SHP header)
;   shxfile    = the .shx file containing the shape (no path, just filename)
;   S=         = scale multiplier (relative to the linetype's overall scale)
;   R=         = rotation in degrees (0=along line, 90=perpendicular, etc.)
;   X=         = X offset from insertion point (shift left/right along line)
;   Y=         = Y offset (shift above/below the line)
; All parameters except SHAPENAME and shxfile are optional

; ─────────────────────────────────────────────────────────────
; REAL EXAMPLE: Gas distribution main line
; Uses the GAS shape from ltypeshp.shx
; Pattern: dash, gap, GAS bubble shape, gap, repeat
*GAS_LINE,Gas Distribution Main — — G — —
A,.5,-.25,[GAS,ltypeshp.shx,S=.1],-.25

; ─────────────────────────────────────────────────────────────
; EXAMPLE: Using your custom shape from a company file
*ELECTRIC_PRIMARY,Electric Primary — — P — —
A,.5,-.1,[PHASE,my_electric_shapes.shx,S=.15,R=0],-.1,.5,-.1

; ─────────────────────────────────────────────────────────────
; EXAMPLE: Shape rotated perpendicular to the line
*FENCE_LINE,Fence — — X — —
A,.25,-.1,[FENCE,ltypeshp.shx,S=.12,R=90],-.1

ltypeshp.shx — AutoCAD's Built-In Linetype Shapes

AutoCAD ships with ltypeshp.shx which is the companion file for complex linetypes. Here are the shapes available in it:

Shape Name	What It Looks Like	Typical Use
BAT	Batting / insulation zigzag	Insulation in wall sections
CIRC1	Small circle	Gas, chemical piping
TRACK	Railroad track cross-tie	Rail lines on maps
FENCELINE1	Fence post (square)	Property fence lines
FENCELINE2	Fence post (circle)	Property fence lines
ZIGZAG	Sawtooth wave	Boundary lines
GAS_LINE	Stylized G	Gas distribution mains
HOT_WATER_SUPPLY	HW with arrows	Plumbing hot water lines

Loading a Custom Linetype That Uses Your .SHX

Make sure your .SHX file is in a folder on the Support File Search Path (AutoCAD must be able to find it by filename alone)
Create your .LIN file referencing your .SHX shape by name and filename (no folder path — AutoCAD finds it via the search path)
In AutoCAD, type -LINETYPE → L for Load → browse to your .LIN file → select your linetype → OK
Apply the linetype to a layer or object. AutoCAD will automatically load your .SHX when it needs to render the shapes.
If the shape doesn't appear (just shows as a plain dashed line), the .SHX is not being found. Check the search path.

⚠ Sharing drawings: When you send a drawing with a custom shape-based linetype to a client or colleague, you must also send your .SHX file. Without it, AutoCAD will render the linetype as a plain dashed line and they'll never know the shapes should be there unless they open the drawing on a machine that has the file.

Common Problems & Fixes

Click any problem below to expand the solution.

Cause: A .SHX font used by a text style in this drawing doesn't exist in your Support File Search Path.

Fix 1 (Best): Get the missing .SHX file. Check with your client, project team, or if it's a company standard, IT/CAD admin. Place the .SHX in a folder in your Support File Search Path (OPTIONS → Files → Support File Search Path).

Fix 2 (Quick): Open the STYLE command, find the style using the missing font, and change it to a font you do have (like romans.shx). Save the drawing. The dialog won't appear again — but text appearance may change.

Fix 3 (Suppress dialog): System variable FONTALT controls which font AutoCAD substitutes automatically. Set it to simplex.shx or romans.shx to silently substitute without the dialog. Not recommended long-term — you'll silently lose the correct font.

Most common causes and fixes:

Wrong byte count: The number in the header *1,23,SHAPENAME must exactly match the number of codes in the definition (count every code including the final 0). Count again carefully.

Missing terminating 0: Every shape definition must end with 0 as the last code. If your definition ends with something else, compilation fails.

Invalid code: Using a code that doesn't exist (e.g., typo like 010O instead of 010). All codes are hexadecimal — check your reference.

File encoding: The .SHP file must be plain ASCII text. If you wrote it in Word or a rich-text editor, hidden formatting characters may cause errors. Open in Notepad and re-save as "All Files" with .shp extension.

Blank last line: Some AutoCAD versions require the file to end with a blank line (press Enter at the very end of your last line). Try adding one.

The linetype loaded but the shape .SHX isn't being found.

Check 1: Is the .SHX filename in the .LIN file spelled exactly right? The filename is case-sensitive on some systems. Compare the .LIN file entry to the actual .SHX filename.

Check 2: Is the .SHX file in a folder listed in Options → Files → Support File Search Path? AutoCAD can't use folder paths in the .LIN file — it must find the .SHX by searching the support path.

Check 3: Is LTSCALE set appropriately? If LTSCALE is set very large or very small, the shapes may exist but be too large/small to see at the current zoom level. Try LTSCALE of 1.0 first and zoom to a line to check.

Check 4: Regen the drawing: type REGEN (or REGENALL). Sometimes loaded linetypes don't display until the drawing regenerates.

AutoCAD quietly substituted a different font.

When the intended .SHX is missing and no substitute dialog appeared, AutoCAD used the font defined in the system variable FONTALT (default: simplex.shx).

Fix:
1. Identify the intended font: open STYLE → look at the font name for the style in question.
2. Obtain and install the correct .SHX file.
3. If you can't get the original, pick a font that's visually close and update the style definition.

Prevention: Keep a copy of all .SHX files used by company standard drawings in a shared network folder that everyone has in their Support File Search Path.

Options for locating rare or proprietary .SHX files:

1. Ask the source: Contact the client or the company that created the drawing. Most .SHX files are company standards and should be provided with the drawing.

2. Check Autodesk's font library: Some fonts from older Autodesk products (like Map 3D, Civil 3D) aren't in base AutoCAD but are available from Autodesk's support pages or forum downloads.

3. CAD community resources: The Autodesk forums and CAD community websites (CADTutor, Autodesk Community) have many user-contributed .SHX font files available for download.

4. Substitute and document: If you genuinely can't find the file, substitute with a visually similar font, note the substitution in the drawing notes/title block, and inform the client. Never silently substitute on final deliverable drawings without notification.

AutoCAD can't find the shape you're trying to insert.

Step 1: You must load the .SHX file first before AutoCAD knows the shape names inside it. Type LOAD, browse to your .SHX file, and load it.

Step 2: After loading, type SHAPE again and enter the shape name exactly as defined in your .SHP file header. Shape names are case-insensitive in modern AutoCAD but type them in uppercase to match the definition.

Step 3: If LOAD can't find the .SHX file, it's not in the Support File Search Path. Add the folder (OPTIONS → Files) or move the .SHX to a folder already in the path.

Two different ways to get .SHX content into AutoCAD:

LOAD command: Explicitly loads a Shape .SHX so you can insert individual shapes with the SHAPE command. Only works with Shape .SHX files, not Font .SHX files. The shapes are loaded into memory for the current session — you may need to reload in future sessions if the file isn't automatically found.

Text Style (STYLE command): Assigns a Font .SHX as the font for a text style. AutoCAD loads the font automatically whenever that style is used. This is the correct way to use font .SHX files for text objects, dimensions, and leaders.

Linetype loading: Shape .SHX files used in complex linetypes are loaded automatically by AutoCAD when the linetype is applied to an object — you don't need to LOAD them manually. AutoCAD finds them through the Support File Search Path.

Quick Diagnostic Checklist

Check	Command	What to Look For
What fonts does this drawing use?	STYLE	Font Name column — every .SHX listed must be in your search path
Are all fonts available?	AUDIT	Audit log will flag missing font files
What's my substitute font?	FONTALT	System variable — shows/sets the auto-substitute font
Where does AutoCAD look for files?	OPTIONS → Files	Support File Search Path — your .SHX folder must be listed here
Shapes not showing in linetype?	REGEN	Regenerate drawing — shapes may need a regen to appear after loading
What linetypes are loaded?	LINETYPE	Linetype Manager — shows all loaded linetypes and whether they're complex

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🔡 SHX & SHP File Guide

The Big Picture

The Three Types of .SHX Files

Why AutoCAD Uses .SHX Instead of TrueType Fonts

Default AutoCAD Font Folder

Adding Your Own SHX Search Path

How to See Which .SHX a Drawing Uses

What Happens When a .SHX File is Missing

AutoCAD's Built-In SHX Font Library

★ The Most-Used Fonts (Know These First)

Complete Built-In Font Reference

How .SHP Files Work — The Basics

.SHP File Structure

Shape Definition Codes — Complete Reference

Core Control Codes

Direction Codes (Hex 010–01F) — The 16 Compass Directions

A Real Example — Reading a Simple Shape

What You Need

Step-by-Step: Create a Custom Shape

Step 1 — Plan Your Shape on Paper First

Step 2 — Write the .SHP File

Step 3 — Compile It in AutoCAD

Step 4 — Load and Use Your Shape

Creating a Custom Font (.SHP with Characters)

Shape .SHX Files and Complex Linetypes

How Shape References Work in .LIN Files

ltypeshp.shx — AutoCAD's Built-In Linetype Shapes

Loading a Custom Linetype That Uses Your .SHX

Common Problems & Fixes

Quick Diagnostic Checklist