Random glitches, flat ucs and icon solid hatch

A colleague of mine could not hatch dots on a drawing at a higher density. I tried the usual regen and measurement commands to see if it was the hatch itself, however it was not to do with this.

After searching it could be a variable issue in the drawing but the drawing was from our standard template, but worth checking to see if HPMAXAREAS and HPMAXLINES were set to low values. They were not.

After further searching it became apparent that the drawing was a long way from the origin causing the glitches. This was apparent because the x leg of the UCS icon kept disappearing on zoom when in world UCS.

The glitches were:

  • Hatches not hatching properly at higher densities
  • ONSNAP not working properly
  • Fillet and trim not working properly

The solution was to create a drawing UCS closer to the drawing that fixed these glitches.

Hatch ribbon slow to load

So the hatch ribbon is slow to load? I found that the addition of custom hatches on a network path was the cause of the issue. Remove the network related path from the support files and the hatch command speeds up considerably. This seems to be a similar problem to that of the MTEXT problem I have encountered previously.

Do You Really Want To Do This?

Sometimes AutoCAD comes up with a notice noting “Do you really want to do this?” when moving hatches or something related to hatches.

This is most likely (in fact most of the time) related to associative hatches and their boundaries needing to be checked during a move, mirror etc. type command.

This does not always happen in all drawings with lots of hatch, in fact I only encounter it occaisionally these days. So AutoDesk is making hatch better, good for them.

A quick and dirty fix for this problem is to select all hatches and make them non-associative. Then everthing works as normal, well except the hatches don’t follow the outlines, but grip edit hatches make up for that!

Hatching and XREFs

It appears that there is a fundamental flaw in AutoCAD where if you clip an XREF the information AutoCAD requires in order to HATCH objects in the XREF is lost, therefore AutoCAD cannot HATCH an clipped XREF. How dumb is that.

Create Hatch

Bizarrely AutoCAD has not (as far as I am aware) created an easy hatch creation method, preferably in a GUI. This is long, long, long outstanding and should have been introduced back in R14 or earlier. If you want to create a hatch, you have to write it out by hand in a text file (there is no automation either), giving the text file a .pat extension.

Apart from the header row for the name and description of the hatch file, the hatch format is like this:

angle, x-origin,y-origin, delta-x,delta-y,dash-1,dash-2

Each line in the text file describes a drawn line, whether this is solid or dashed. All patterns are made from lines that are dashed or continuous and nothing else (a dot a line with a very short or no length). The dash length is variable so you then build up a hatch patten from a set of dashed lines that intersect. 

In order to create say herringbone brick you have the following pattern text:

0, 0,0, 10,10, 30,-10
90, 20,-30, -10,10, 30,-10

This creates a dashed line one way that intersects with one 90 degrees to it and when they repeat a brick pattern occurs. For such a simple shape it is still quite hard to wrap your head around the way they work!

If a complex hatch is required it is expected of the user to somehow translate their drawings from a set of lines into the hatch format. This is of course nigh-on impossible for most users and for a pattern with over one hundred entities will take forever to measure and write out the results, and the 7 step help file isn’t really that helpful and is quite vague.

This is one my major annoyances in AutoCAD that they fiddle with this and that and don’t fix fundamentally missing features like this!


If you are thinking, man I cannot do that, don’t worry if you have the full version of AutoCAD (sorry LT guys) you can install a LISP file to do this for you. The awesome guys at Cadalyst posted in one of their tips a hatch creation LISP.

This LISP has two functions, draw and save. Accessed through DRAWHATCH and SAVEHATCH (strangely enough).

The draw hatch command command creates a 1×1 box in drawing units, so for metric in my case this is a 1x1mm box. Tiny!


So this is the process I followed to create my hatch.

Firstly, draw your tessellating hatch inside a square, using only line entities. Make sure no curves are present. Then copy this in all directions to make sure the tessellation works! Save this drawing as your template for the hatch.

Secondly, scale your square down to a 1×1 unit square. You can save this as another file if you want. Leave this drawing open (save first, as always before doing anything major).

Thirdly create a new drawing and run DRAWHATCH. This will create a 1×1 unit square with nothing in it. Go back to your open drawing and copy the entities within the square (you can copy the square for ease and delete it after the copy if you want), and paste inside the square drawn in the new drawing by DRAWHATCH.

Fourthly, run SAVEHATCH and select the line objects (polylines won’t work so explode them first) and follow the prompts. A command line window will appear to make things easier.

Fifthly, give it a description and then save it as a file name in a place where you can load them into AutoCAD. Our practice as a server folder for custom hatches.

So that’s it you now have a hatch. One of the problems I encountered with this method is that the created hatch is very small. You will have to enter a large scale factor to correct this.


If you are feeling adventurous, you can load the pattern file into Excel and scale the numbers created up to suit. Save out as CSV to get the comma delimited text file back!