Hatches
A hatch that won't generate is almost always a boundary problem. Fix the boundary.
Why this matters
Hatches represent materials on plan drawings — pavement types, planting beds, turf areas, water surfaces, and ground conditions. They communicate what a surface is made of and, by extension, how a space functions and feels. A drawing without hatches is a line drawing. A drawing with hatches is a plan. The difference matters for everything from design review to client presentation. Hatches have different meanings in section than they do in plan.
How hatches work
The HATCH command (H) fills an area bounded by closed geometry with a repeating pattern. The boundary must be completely closed — any gap, even one too small to see at normal zoom, will cause the hatch to fail or behave unexpectedly. This is not negotiable. If a hatch won't generate, the boundary is the problem.
The Z — Hatchline layer
The most reliable boundary method is to draw explicit closed polylines on the Z - Hatchline layer before hatching. Do not rely on AutoCAD's boundary detection from overlapping geometry — it works some of the time, which means it fails enough to cost you time when it matters. Draw a dedicated boundary polyline on Z - Hatchline, close it with PL + C or PEDIT + C, then hatch to that boundary.
The Z - Hatchline polyline is the container. The hatch itself goes on the appropriate content layer: L - Plant - Hatch, L - Walk - Hatch, L - Walk - Hatch - Existing, etc. These are different layers serving different purposes.
Hatch settings
| Setting | What it controls | Note |
|---|---|---|
| Pattern | The graphic symbol — concrete, gravel, earth, turf, etc. | Use industry-standard material conventions. AR-CONC for concrete. GRASS for turf areas. |
| Scale | The density of the pattern at the current drawing scale | A scale that looks right at 1"=20' will be too fine at 1"=100'. Adjust per drawing scale. |
| Angle | The rotation of the pattern | Useful for differentiating similar materials in adjacent areas. |
| Associative | Whether the hatch updates when its boundary changes | Keep associative on — it means the hatch follows boundary edits. Non-associative hatches detach on boundary changes. |
| Draw Order | Whether the hatch appears above or below other objects | Hatches should typically be sent behind linework — Send to Back after placing. |
Hatch scale by drawing scale
Pattern density is scale-dependent. A hatch scale of 1 looks correct on a detail at 1"=1'. At a site plan scale of 1"=50', that same scale factor renders as an invisible solid or a near-invisible density. Scale up proportionally to the drawing scale. As a rough starting point: multiply the pattern scale by the plot scale denominator divided by 12. A 1"=50' drawing (1:600) needs a scale factor roughly 50× what you'd use at 1"=1'.
Try this
Draw an irregular closed shape. Hatch it successfully. Then use PEDIT to open one vertex and leave a gap in the boundary. Try to rehatch the same area and observe the failure or unexpected behavior. Then close the gap with PEDIT and rehatch. You've just reproduced the most common hatch problem and its solution — now you'll recognize it immediately when it happens on your drawing.
What breaks
Open polyline boundaries cause hatch failures every time. The gap is almost always invisible at the zoom level you're working at. Zoom in to every corner and endpoint to verify closure before hatching. Better: use PEDIT + C to close the polyline mathematically and eliminate the question.
Associative hatches losing their boundary — if you delete or move a boundary polyline after hatching, the associative hatch either follows (if the boundary was moved) or becomes orphaned (if it was deleted). Orphaned hatches are harder to edit. Keep boundary polylines in place or use non-associative hatches if the boundary will change significantly.
Hatch on the wrong layer — hatch objects should be on content layers, not on Z - Hatchline. Z - Hatchline holds boundary polylines only. The hatch itself communicates material and belongs on the layer that describes what it represents.