Free Hatch Pattern Generator for AutoCAD and Revit

Build a custom hatch pattern in your browser: choose a brick bond, tile, herringbone, plank, dash or dot pattern, type the real sizes and watch the preview repeat to scale. Download it as an AutoCAD .pat file, as a Revit model or drafting fill pattern in millimetres or inches, or as a seamless SVG or PNG tile for Illustrator, Inkscape, Figma or Photoshop. The files are written in your browser, nothing is uploaded and there is no sign up.

How to use this hatch pattern generator

1. Pick a pattern type. Parallel lines (ANSI31 style), cross hatch, brick in running, third or stack bond, herringbone, basketweave, square, rectangular or hexagon tiles, staggered wood planks, parquet, dashed lines, dots or concrete stipple. Custom line families lets you build a pattern by hand.
2. Set the design units and sizes. Choose millimetres or inches, then the unit length, height and joint width; the brick bond starts at 215 x 65 mm with a 10 mm joint. Draw joints as one line (the joint centre, usual for drafting) or two lines (both joint edges, usual for large scale elevations).
3. Check the preview. The dashed red rectangle is one repeat tile, and lines must meet cleanly across its edges. Drag or use the arrow keys to pan, plus and minus to zoom, and Fit to go back to a few repeats. The grid and scale bar are in real units.
4. Download the CAD file. Set the file units and, for Revit, Model or Drafting, then press AutoCAD .pat or Revit .pat. The AutoCAD pattern name always ends in _MM or _IN, so the millimetre and inch files never overwrite each other.
5. Or download a tile. For Illustrator, Inkscape, Figma or Photoshop, choose a tile scale (auto, or 1:1 to 1:100) and a tile pen from 0.13 to 0.7 mm, then press SVG tile or PNG tile. Both are sized on paper at that scale, so the line weight does not depend on your zoom. The PNG tile is 300 dpi and says so in the file.
6. Fine tune. Edit line families copies the pattern into a table where you can change any angle, origin, offset or dash value. Open .pat file reads an existing AutoCAD or Revit file, including files with many patterns.
7. Write a linetype. The Linetype (.lin) tab writes AutoCAD linetypes such as DASHED, HIDDEN, CENTER and PHANTOM with your own dash and gap lengths.

Save JSON keeps the setup for later, Copy text puts the file on the clipboard, and Print gives a one page sheet of the tool.

How the .pat file is built

Every hatch pattern, in AutoCAD and in Revit, is a set of line families. One family is one line of the file:

angle, x-origin, y-origin, delta-x, delta-y, dash-1, dash-2, ...

• The first line of the family passes through the origin at the given angle.
• Each next line is found by moving delta-y at right angles to the lines and delta-x along them. Delta-x only matters for dashed lines: it slides the dash sequence along, which is what staggers brick joints.
• Dashes are positive numbers, gaps are negative and 0 is a dot. The sequence repeats along the whole line. A family with no dash values is a continuous line.

The classic ANSI31 hatch for brick and stone is a single family, 45, 0,0, 0,.125: lines at 45 degrees, 0.125 inch apart. A running bond of 215 x 65 mm bricks with 10 mm joints, drawn as one line per joint, needs two families:

• 0, 0,0, 0,75 draws the bed joints, one every 75 mm (65 mm brick plus 10 mm joint).
• 90, 0,0, -75,112.5, 75,-75 draws the head joints. They are vertical, one every 112.5 mm, and each one is drawn for one course and skipped for the next. The shift of 75 mm along the line moves the dash by a course each time, which offsets the joints by half a brick.

The generator does this arithmetic for you and merges joints that fall on the same line, so nothing is drawn twice. The file and the preview come from the same list of families, so what you see is what AutoCAD or Revit will draw.

For which hatch stands for which material, see our guide to architectural hatch patterns. This page sticks to making the file.

AutoCAD .pat or Revit fill pattern: what changes in the file

Revit reads the same line family format as AutoCAD, but the two programs disagree on the details around it. The generator writes each version to its own rules, which is why there are two download buttons.

Rule	AutoCAD .pat	Revit .pat
Header lines	none, just *NAME, description	;%UNITS=MM or INCH, ;%VERSION=3.0
Pattern type	not used	;%TYPE=MODEL or ;%TYPE=DRAFTING under each pattern header
Pattern name	at most 31 characters: letters, digits, underscore, hyphen and dollar sign	any ASCII text except a comma, spaces allowed
Line length	at most 80 characters	up to 4096 characters
Dash values per line	at most 6	no such limit
File	one pattern per file, named after the pattern, with a blank line at the end	one file can hold many patterns
Dots	drawn as dots	drawn as very short dashes

When a family needs more than six dash values or a line would pass 80 characters, the generator splits it into several families that draw exactly the same thing. The AutoCAD rules are set out in the Autodesk AutoCAD Customization Guide, under About Custom Hatch Patterns and Hatch Pattern Definitions. The Revit rules come from the header of the revit.pat file that ships with Revit.

Model or drafting pattern?

This choice only exists in Revit, and it decides what happens when the view scale changes.

• Model patterns are real sizes. A 215 x 65 mm brick stays 215 x 65 mm at every scale, so it looks denser at 1:100 than at 1:20. Use them for brick, block, tile, cladding and planks. Typical sizes are 50 to 500 mm.
• Drafting patterns keep the same printed size at every scale. Use them for symbolic hatches such as concrete, sand, earth and insulation. Typical sizes are 1 to 25 mm on paper.

The generator warns you when the size looks wrong for the type you picked. It is a hint, not an error.

Brick bonds, tiles and wood floors

• Brick bonds. Running bond offsets each course by half a unit, third bond by a third, quarter bond by a quarter and stack bond not at all. Random look uses a five course sequence of offsets that reads as irregular but still repeats, because a .pat file can only describe a repeat.
• Herringbone. Choose the 45 degree chevron or the 90 degree layout square to the edges. Length plus joint divided by width plus joint must be a simple fraction (2, 2.5, 3 or 13/10, for example), or the layout never repeats; the field tells you the rule and suggests a length that works. For bricks with joints, use length = 2 x width + joint, such as 215 = 2 x 102.5 + 10.
• Basketweave and parquet. Set the strip width and 2 to 10 strips per block.
• Tiles. Square tiles start at 300 mm with a 3 mm joint, rectangular tiles at 600 x 300 mm with a half offset. Hexagons are sized across the flats, pointy top or flat top.
• Wood planks. Staggered planks start at 1200 x 150 mm with the random look, closer to a real floor than a regular half offset.
• Dashes, dots and concrete. Dashed lines take a spacing, dash and gap, an optional dot in every gap and a stagger. Dots come in a square or triangular grid. Concrete stipple scatters dots and aggregate triangles in a repeat tile from a random seed; change the seed for a different scatter.

How to load the file into your software

• AutoCAD. Save the file under the name the generator gives it, for example la_running_215x65_mm.pat for the pattern *LA_RUNNING_215X65_MM, in a folder that is on the support file search path (Options, Files tab). Run HATCH and pick the pattern from the list of custom patterns. If your browser adds ” (1)” on a second download, rename the file: AutoCAD needs the file name to match the pattern name.
• Revit. Go to Manage, Additional Settings, Fill Patterns, choose New, then Custom, then Import, pick the downloaded file and choose Model or Drafting to match the file.
• Illustrator, Inkscape and Figma. Use the SVG tile. Its width and height are paper millimetres at the tile scale you chose, so the line weight on paper matches the pen. In Illustrator, drag the SVG into the Swatches panel to make a pattern swatch.
• Photoshop. Open the PNG tile, which is one seamless repeat at 300 dpi, and use Edit, Define Pattern.

Seamless tiles need a rectangular repeat. At an odd angle such as 10 degrees most patterns have none, and the tool says so: the .pat file is still correct, but there is no SVG or PNG tile to export.

Common problems and their fixes

• The pattern is 25.4 times too big or too small. An inch file was read as millimetres, or the other way round. Download again with the right file units. For AutoCAD, use the millimetre file in an acadiso drawing and the inch file in an acad drawing.
• AutoCAD refuses to draw the hatch. AutoCAD stops when a hatch would create too many lines for the area, a limit set by the HPMAXLINES system variable. Raise the hatch scale or hatch a smaller area. The preview behaves the same way and says “too dense to draw” instead of freezing your browser.
• AutoCAD does not list the pattern. Check that the file name matches the pattern name, that the file is in a support folder, that the name is 31 characters or less and that there is a blank line after the last line. The generator writes all four correctly, so the usual cause is a renamed file.

Linetypes (.lin) for AutoCAD

The second tab writes linetype files in the simple AutoCAD format: a header line *NAME,description followed by A,dash,gap,.... Start from one of the acad.lin definitions (DASHED, HIDDEN, CENTER, PHANTOM, DOT, DASHDOT, BORDER, DIVIDE) and change the values, or type your own sequence. In millimetres the presets are the acadiso.lin values, which are the inch values times 25.4.

The tool checks the AutoCAD rules as you type: a definition needs 2 to 12 values, the first value must be a dash or a dot (0 or more), the name can have at most 31 characters and the description at most 47. The preview shows the linetype at three scales. Revit has no linetype file: create line patterns under Manage, Additional Settings, Line Patterns, with the same dash and space values.

What this hatch generator does not do

A .pat file can only hold straight line segments: no arcs, curves, solid fills or true randomness. Stone with curved edges or organic textures cannot be written as a hatch, and the concrete stipple is a scatter that repeats. If you need curves, use an image tile instead. The tool also does not copy the internal density limits of AutoCAD and Revit, which Autodesk does not publish; it warns about typical Revit sizes and stops the preview when a pattern is too dense to draw.

Frequently asked questions

Is this hatch pattern generator free?

Yes. There is no account and no sign up, and the files are built in your browser. Nothing you draw or open is sent to a server.

Can I use the .pat file in Revit?

Yes, but download the Revit version. It starts with ;%UNITS=MM (or INCH) and ;%VERSION=3.0 and marks each pattern ;%TYPE=MODEL or ;%TYPE=DRAFTING. Import it from the Fill Patterns dialog and pick the same type.

Why does AutoCAD not show my custom pattern?

The file name must match the pattern name, the file must be in a support file search path folder, the name must be 31 characters or less and there must be a blank line after the last line. The generator writes all of this; check that the file was not renamed by your browser on a second download. Autodesk lists the same checks in Why can’t I use my custom hatch pattern (PAT) files?

Can I open and convert an existing .pat file?

Yes. Open .pat file reads AutoCAD and Revit files up to 2 MB, lists every pattern in the file and previews the one you pick to scale. Units come from the ;%UNITS line, or you can set them by hand. You can then edit the pattern and export it again, for example to turn an inch AutoCAD pattern into a Revit millimetre model pattern.

Can I add the hatch to a title block or a drawing sheet?

The hatch goes into your drawing. For the sheet, the title block generator draws the frame, title block and revision table at true paper size and exports DXF.