Why do hatches become difficult to manage in complex drawings?

[indiancad]

In detailed engineering drawings, hatching can become frustrating when boundaries contain many small edges, gaps, or overlapping objects. A hatch may fail to generate, fill an unintended area, or become difficult to edit after the geometry changes.

 

Increasing the gap tolerance can sometimes help, but it may also cause the hatch to cross boundaries that should remain closed.

 

How do you troubleshoot hatch problems in drawings with complex boundaries? Do you repair the geometry first or use a different hatching approach?

Edited yesterday at 09:40 AM by indiancad

[CyberAngel]

When I run into a situation like this, the complexity or the effort can become too much, especially if there's a deadline. In that case I'll draw a polyline along the border and use that as the boundary for the hatch. Of course the polyline goes on a nonplotting layer.

[SLW210]

AutoCAD is terrible at hatching in several ways, that at least usually is reported by BricsCAD users to do better with the same shape(s).

 

Several threads here and other forums of quirks for this and that on hatching.

 

On another forum, someone posted a spline shape that didn't hatch correctly, though I was able to "FIX" it by offsetting it (with delete option) and then offset it back where it was also with delete option), it also worked fine originally with several hatch patterns and failed on a few others, it also had no issues in BricsCAD reportedly. Sometimes zooming in or zooming out and/or moving closer to 0,0,0 works.

 

Sometimes just using a slightly different pattern works better.

 

I mostly use Solid, Gradient, Steel, Aluminum, et. al. made of straight lines and usually they work better in most instances, seldom do I need Earth, Gravel, Sand, etc. which seems to be the type to have issues.

[Paul Li]

Some times with very odd shaped boundaries AutoCAD just has a hard time filling it with any hatch pattern. That's when I would break the single hatch area up into different area sections. The boundary would be drawn using a PLINE and placed onto a non-plot layer. This usually resolves the issue. Another solution that worked for me involves odd shaped boundaries that are symmetrical. The hatch area when broken up in half hatches perfectly on the left side but refuse to hatch properly on the right. So I would just create the hatch pattern on the side that works and then mirrored that to the other side.

[SLW210]

A lot of times if you use the object option it does better. When I get back to work, I'll see how many old threads are around on hatch and boundary issues.

[indiancad]

10 hours ago, SLW210 said:

AutoCAD is terrible at hatching in several ways, that at least usually is reported by BricsCAD users to do better with the same shape(s).

AutoCADtutorials

 

 

Several threads here and other forums of quirks for this and that on hatching.

 

On another forum, someone posted a spline shape that didn't hatch correctly, though I was able to "FIX" it by offsetting it (with delete option) and then offset it back where it was also with delete option), it also worked fine originally with several hatch patterns and failed on a few others, it also had no issues in BricsCAD reportedly. Sometimes zooming in or zooming out and/or moving closer to 0,0,0 works.

 

Sometimes just using a slightly different pattern works better.

 

I mostly use Solid, Gradient, Steel, Aluminum, et. al. made of straight lines and usually they work better in most instances, seldom do I need Earth, Gravel, Sand, etc. which seems to be the type to have issues.

Interesting point about different hatch patterns behaving differently with the same boundary. I hadn’t considered that moving the geometry or changing the pattern could sometimes help. It shows that the issue isn't always just the boundary itself.

[indiancad]

9 hours ago, Paul Li said:

Some times with very odd shaped boundaries AutoCAD just has a hard time filling it with any hatch pattern. That's when I would break the single hatch area up into different area sections. The boundary would be drawn using a PLINE and placed onto a non-plot layer. This usually resolves the issue. Another solution that worked for me involves odd shaped boundaries that are symmetrical. The hatch area when broken up in half hatches perfectly on the left side but refuse to hatch properly on the right. So I would just create the hatch pattern on the side that works and then mirrored that to the other side.

Breaking a complicated area into smaller sections makes sense, especially when only part of the boundary is causing trouble. Mirroring a hatch across a symmetrical part is also a useful workaround I’ll keep in mind.

[indiancad]

15 hours ago, CyberAngel said:

When I run into a situation like this, the complexity or the effort can become too much, especially if there's a deadline. In that case I'll draw a polyline along the border and use that as the boundary for the hatch. Of course the polyline goes on a nonplotting layer.

That’s a smart workaround, especially when you’re up against a deadline! Using a polyline on a nonplotting layer seems much easier than trying to fix every tiny gap in the original boundary.

[indiancad]

7 hours ago, SLW210 said:

A lot of times if you use the object option it does better. When I get back to work, I'll see how many old threads are around on hatch and boundary issues.

Good point. Using the object option can simplify things when the existing geometry already defines a usable boundary.

[Paul Li]

Just thought of another trick I've used in the past. I would let AutoCAD create a brand new outline of the area to be hatched for me with the Boundary command. But in the Boundary Creation window under Boundary set, do not use the default Current viewport setting. But instead click on the New button and then select only the objects that form the hatch area outline. This restricts AutoCAD to only consider those objects selected to generate the new boundary. Leave the Object type as Polyline and usually with this new Pline boundary generated, the Hatch creation completion success rate would increase just a tad more.

[SLW210]

IIRC, I have just frozen all layers (or use LAYISO is usually easier) except what I need or even create a couple of new layers and only have those on.

 

You can also try tweaking the scale, angle, etc.