hatch, hatching problems, hatch boundary, polyline

[zeulrick]

I have always had some general frustration with Autocad's ability to hatch elements of the drawing. When I upgraded my pc, I saw a slight improvement to the capabilities of creating hatched elements.

Please find attached screenshot of the type of problem that I consistently have. As you can see, the tile pattern has spilled into objects that should not be hatched. These objects are not blocks, I have outlined them with one continuous polyline to try to help keep the hatching out and to determine hatch boundaries. In this case the hatch won't trim either. I do this with a lot of objects and sometimes it works, sometimes it doesn't. I have found that making a solid fill in the object that will plot white helps but I don't like having to do this, sometimes it only adds more time and commands.

What other solutions are there? Does anyone have any cool tricks and tips? 

Much appreciated!

[natasha.l]

Hello @zeulrick, 

You want to make sure you have set your hatch boundaries during the selection or you have the option to edit these boundaries. Also make sure you are using closed ploylines. 

The process: 

Type Hatch command > Select the sink block > then select the wall rect. > right-click Enter

https://autode.sk/2XMMVgy

Please "Accept Solution" if a reply or replies have helped resolve the issue or answered your question, to help others in the community.

[s.borello]

How did you hatch?  Did you select object or pick internal point?  How do you have your island detection set? Are you able to post a sample for us to evaluate? 

[zeulrick]

I usually like to choose an internal point with the island detection at "outer".

When it works, it works extremely well....but it doesn't always work, and creating closed polylines for many objects in a drawing is a pain. So...the image attached below is a typical hatch that I create and it often needs to be modified project to project. 

Sometimes it seems very arbitrary how well AutoCad determines the hatch boundary. 

[scot-65]

The best solution for island detection is to take the islands out of the analyzing.

Draw a vertical DEFPOINT line from the bottom of the mirror (midpoint) to the
top of the lav (and possibly also the p-trap to the view box/ground line).

Draw a vertical DEFPOINT line from the underside of the grab bar to the view box
that is below the toilet.

If you have a pen color (CTB) that has Grayscale On and Screening to 0% one
can draw a line using that color while remaining on the current layer.

Leave these lines in the drawing after hatching so association can be maintained.

It is second nature for me now to employ these methods when rendering
elevation by adding textures to wall surfaces where island windows and
roof textures where island dormers.

If one sees red circles after analyzing, increase HPGAPTOL and try again.

Internal point selection likes to see final hatch shapes that represent the
following letters: C, E, F, G, H, I, J, K, L, M, N, S, T, U, V, W, X, Y, Z.

Internal point selection can be stubborn for hatch shapes that represent
the following letters: A, B, D, O, P, Q, R.

???

[zeulrick]

I like your above answer, even though I'm not so sure I want to have defpoint lines remaining in my drawing. I will test out this method...

What do you mean by "Internal point selection likes to see final hatch shapes that represent the
following letters: C, E, F, G, H, I, J, K, L, M, N, S, T, U, V, W, X, Y, Z."

Do you mean the shapes "look" similar to those capital letters?

[S.Faris]

As a regular Autocad user, I understand the frustration this can cause. But in my experience most of the times this has something to do with the properties of the elements that are part of the boundary selection. If you could attach the file, Maybe we can just check, if the 2d elements have anything to do with this behavior.

[zeulrick]

Please find attached example of the problem.

[DanielSanders4280 · Accepted solution]

I think the duplicated geometry of the toilet perimeter had something to do with this particular issue. I closed the outer (rectangular) polyline border, and removed the individual pieces of the toilet perimeter, keeping only the closed polyline, then it works fine for me. Used non-associative hatch, outer island detection, "pick points" option. Just as a note, a quick & easy method of creating a closed polyline from a collection of arcs, lines, etc. forming an object perimeter is to use the BOundary command, polyline option. Sometimes easier than joining many small segments.

[DavidRRUMCC]

Been using AutoCAD for years and drawing a polyline whenever I want to make sure a hatch doesn't get F'd up. The Boundary command is something I have not used before... so thank you for mentioning it! I might actually use hatches a bit more often, and not just when the "need" arises. I have pretty much taken to avoiding the use of hatches because of how terrible the island detection is, which, imo, is okay if the material subject matter is consistent (I work in the precast industry, where most all of my sections should "technically" have a concrete hatch, but it is an incredible pain sometimes to even think of doing it "proper".)