Hatching and fills

Pattern scale is relative to the pattern's definition, so there's no universal right number. Use the ribbon preview and adjust until spacing looks right at the printed scale. Make the hatch annotative where the pattern represents a drawing convention (not real-world size), so it prints the same at any scale. For patterns that represent real materials (e.g. a 230 × 76 brick coursing), use a real-world scale.

Areas inside the boundary — a column in a slab, text in a room — are islands. Normal island detection hatches alternate areas; Outer hatches only the outermost area.

Leave Associative on: moving or stretching the boundary updates the hatch. Double-click a hatch to edit its pattern, scale or boundary.

A closed boundary cannot be determined means there's a gap. Zoom in on corners, close gaps with FILLET radius 0 or EXTEND, or raise Gap tolerance in the hatch options. Draw a closed polyline around the area and select it — the most reliable method on complex drawings.

Very large or dense hatches slow drawings down; hatch only what you need.

Solid fills can cover linework. Select the hatch and use Send to Back (DRAWORDER), or set hatch draw order to Send behind boundary in the ribbon before creating it.