2.4Hatches, fills & gradients
Hatches fill an area with a pattern: they symbolize materials (concrete, soil, insulation…), distinguish cut surfaces, or highlight zones. The HATCH (H) command applies a pattern inside a closed boundary, with control over the pattern's scale and angle.
Two key points: the pattern must be associated with a closed area (AutoCAD detects the boundary on click), and hatches can be associative — they adapt automatically if the boundary changes shape. There are also solid fills and gradients (color transitions) for presentation renderings. Well set up (adapted scale, dedicated layer), hatches make a plan legible and standardized.
Section vocabulary
- Hatch (HATCH / H)
- Fill of a closed area with a pattern (lines, symbols) representing a material or a surface.
- Hatch pattern
- The repeated fill drawing (ANSI31 for steel, concrete, soil…), with adjustable scale and angle.
- Associative area
- Hatch linked to its boundary: it updates automatically if the boundary is modified.
- Hatch scale
- Density of the pattern; to be adjusted so it is legible (neither too tight, nor too loose) at the print scale.
- Gradient
- Fill with a color transition, mainly used for presentation renderings.
Why does a hatch refuse to be created?
In practice — Applying material hatches
- Create a layer dedicated to hatches, then launch HATCH (H) and click inside a closed boundary.
- Choose a pattern (e.g. ANSI31), then adjust its scale and angle until the rendering is legible.
- Check associativity: modify the boundary and notice the hatch adapts.
- Test a solid fill (Solid) and a gradient for a presentation area.
Key points to remember
- Hatches symbolize materials and cut surfaces.
- They apply to a CLOSED area (boundary detection on click).
- Adjust the pattern's scale and angle for legibility.
- Associative hatches adapt to boundary modifications.
Frequently asked questions
My hatch won't create / « boundary not valid », why?
It's almost always that the area isn't perfectly closed: there's a tiny gap between two lines, or objects overlap badly. AutoCAD can only hatch closed boundaries. Check and close the boundary (Fillet radius 0, Trim/Extend), or use the gap tolerance option. Working cleanly at level 1 (closed drawings) avoids this classic problem.
My hatch is all black or invisible, what should I do?
It's a scale problem: if the pattern is too dense for the area size, it appears as a black mass; if it's too loose, it looks empty. Adjust the hatch scale until the rendering is correct. The scale depends on the real size of the drawing and the target print scale. This is the most frequent setting to fix on hatches.