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#80662 by stephen11962
Thu Feb 17, 2022 4:03 pm
Out of the box there are hatches with stars, squares, etc, but none of varying size holes on a 60* grid. Does this animal exist and is it available? I would be most thankful.

Stephen
#80685 by joshhuggins
Sun Feb 27, 2022 1:33 am
Can you post an example of what you are looking for or what you are trying to represent?
#80686 by stephen11962
Sun Feb 27, 2022 10:52 am
I was looking for a representation of perforated metal using circular holes on a 60* grid, not the usual X/Y axi(?).

There are DC hatches using 60*. I did a dot hatch @ 60* and also constructed what I am looking for. Attached aec file. I imagine that it is (would be) possible to vary the grid dimension as well as the hole diameter.

Stephen
Attachments
(10.47 KiB) Downloaded 65 times
#80687 by dhs
Sun Feb 27, 2022 12:53 pm
I believe it would be possible to create a hatch. Edit: On further investigation, it would be extremely difficult to create a hatch that repeated circles approximated by a large number of straight lines due to the way each segment is repeated on an infinite line through the segment.
Hatch patterns have to have repeats, in X and Y directions
The pattern would need to represent an area that could be repeated in X, Y such as that shown in the red rectangle below: Edit: this is incorrect. Each inividual line in the hatch pattern can define it's own repitition - dh .
image_2022-02-28_045832.png
image_2022-02-28_045832.png (3.35 KiB) Viewed 1148 times

circles as part of a pattern is tough to do.
Hatches are defined using lines (place pen, pen down, move in a straight line to a new position, pen up etc.) so the circles would need to be drawn using straight segments. If the hatch is not going to be shown at a large scale then 36 segments would probably be adequate? Edit: hmmm - I might have been thinking of something else when I wrote this - it is not exactly how the hatch is defined (see comments from MFM towards the end of this thread) - dh.

There is an old Cheap Tricks article about defining hatches so you may be able to work out how to define it. I am very busy with things non-DataCAD just at the moment, but may have a look at creating a hatch based on your example at some stage when I have some spare time if somebody else hasn't already done so by then ...
Last edited by dhs on Thu Aug 04, 2022 4:19 pm, edited 1 time in total.
#80688 by Roger D
Sun Feb 27, 2022 1:03 pm
there is a HTCH_MGR macro that might help in creating the hatch.
#80689 by Joseph Baron
Wed Mar 02, 2022 3:13 am
Since I'm out of work I spent some time over the last few days and figured this out.

I have a custom hatch as per the file using a Dodecagon, a 12 sided shape.

I've invested the hours and it's taught me a lot and can probably create any needed custom hatch at this point. Who knows maybe I can get some side work? :wink:
#80695 by stephen11962
Wed Mar 02, 2022 2:08 pm
I started this, more out of curiosity since I was doing a detail that could have used what I was asking for. I never thought that it would be so time consuming and I have decided that I could cover the issue with a 'simple' note.
#80696 by Mark F. Madura
Wed Mar 02, 2022 4:42 pm
The hatch pattern definition is difficult to visualize when you need to use segments (versus infinite lines). For a 12-sided 'circle', 12 segments are required. So the Dodecagons will be made up of 12 dashed lines repeating perpendicular to six different angles.

The comma-delimited format for each 'Segment' (dot, infinite line, or segment(s)) is the following:
Note: All values are in Decimal Degrees or Decimal 32nds
(1) Line Weight (required, but ignored)
(2) Line Color (required, but ignored)
(3) Angle for the 'Segment'
(4) Starting X-Offset from the origin of the pattern
(5) Starting Y-Offset from the origin of the pattern
(6) Delta-X, tangent to the Segment Angle (only used for dashed lines)
(7) Delta-Y, perpendicular to the Segment Angle (i.e. the spacing)
(8, 9, 10, 11, 12, 13) Optional Line Pattern (i.e. Dashes). Negative values are 'gaps'
#80698 by Joseph Baron
Wed Mar 02, 2022 9:13 pm
Thanks Mark!

I enjoyed figuring this out in a custom hatch file and by the time I was done I have an easy way to get the distances out of DataCAD and quickly converted into the line format required for the DHP files to paste it back in.

In a past life I worked in the metal panel industry and when we fabricated perforated panels these custom hatches could have saved some time with large scale elevations and details and of course be reusable for standardized patterns, and I'm always up for learning something new in DataCAD! :)
#81311 by dhs
Thu Aug 04, 2022 3:19 pm
MFM wrote:
The hatch pattern definition is difficult to visualize:

It is indeed a bit difficult to visualize (even with Mark's explanations).
I found a good analysis of the definition of AutoCAD hatch patterns at http://www.cad-addict.com/2009/04/autocad-understanding-pat-hatch-pattern.html. It doesn't have the first 2 values (which are ignored anyway), but otherwise seems to match Mark's definition with graphics that more clearly illustrate (to me anyway) the exact meaning of the various values (noting that my previous contribution to this thread was not entirely accurate).

David H.
#81313 by dhs
Thu Aug 04, 2022 6:27 pm
As each segment in the hatch pattern is repeated along its direction, it will be very difficult (probably not impossible, but close to it), to design a circle hatch with more than a dozen or so segments in each circle....

I had made a note of this thread as I thought it may be interesting to write a HatchMaker macro at some stage (don't know anything about HATCH_MGR macro that Roger mentioned - perhaps somebody has details of it??). I've abandoned the macro idea as I can see that there will be many difficulties in calculating the repeats for lines that can head in any direction...

But I couldn't bring myself to completely abandon the challenge ... and thought that if the lines didn't have any direction then it would be pretty easy as I could define the repeat direction without having to worry about the line direction. ...
The only lines that don't have direction are dots, so it is pretty easy to create a hatch with dots defining any pattern. I know that is not what was asked for, but it seems like it could be a solution in some circumstances, so I created a hatch pattern that consists of dotted circles (with dots at 20 degree increments, or 18 in a full circle, although it would not be hard to create more):
circle hatch.png
circle hatch.png (25.66 KiB) Viewed 125 times

The definition below draws 25.4mm (1") circles at a hatch scale of 1:
Code: Select all[Header]
Scale=1
Angle=0
Display Scale=7
Segments=9

[Segments]
001=0,0, 0, 16,0, 32,55.425625842204073392878282928188, 0,-32,0,-32
002=0,0, 0, 15.0350819325745,5.4723222932107, 32,55.425625842204073392878282928188, 0,-33.9298361348509,0,-30.0701638651491
003=0,0, 0, 12.2567110899036,10.2846017549846, 32,55.425625842204073392878282928188, 0,-39.4865778201927,0,-24.5134221798073
004=0,0, 0, 8,13.856406460551, 32,55.425625842204073392878282928188, 0,-48,0,-16
005=0,0, 0, 2.77837084267089,15.7569240481953, 32,55.425625842204073392878282928188, 0,-58.4432583146582,0,-5.55674168534178
006=0,0, 0, 15.0350819325745,-5.4723222932107, 32,55.425625842204073392878282928188, 0,-33.9298361348509,0,-30.0701638651491
007=0,0, 0, 12.2567110899036,-10.2846017549846, 32,55.425625842204073392878282928188, 0,-39.4865778201927,0,-24.5134221798073
008=0,0, 0, 8,-13.856406460551, 32,55.425625842204073392878282928188, 0,-48,0,-16
009=0,0, 0, 2.77837084267089,-15.7569240481953, 32,55.425625842204073392878282928188, 0,-58.4432583146582,0,-5.55674168534178

I've attached a zip of the .dhp file that contains the above definition.

Rgds,
David H.
Attachments
(407 Bytes) Downloaded 7 times
#81327 by dhs
Sat Aug 06, 2022 5:42 pm
Quite possibly nobody will ever use it, but I couldn't help myself:

After using Excel to create most of the content in my dotted circle hatch in the previous post, I realised that it would be pretty easy to create the entire hatch in Excel and to base it on parameters such as number of dots and circle spacing...

The resulting Excel file is attached (note that Excel may disable functionality on downloaded spreadsheets - you will probably need to Enable Editing, and then Enable Content in order to use the spreadsheet).
I have limited the number of dots to 512 (simply because it seemed like a nice round number - I think DataCAD can handle up to 999, not sure if it can do more than that) and the spacing to a minimum of 1/10th the circle diameter (which will produce very overlapped circles). Other than that you can specify pretty much what you want to create patterns such as those shown below:
CircleVariations.png
CircleVariations.png (13.95 KiB) Viewed 94 times
Attachments
(34.43 KiB) Downloaded 8 times
#81328 by Roger D
Sun Aug 07, 2022 11:15 am
could one do a similar effect using the existing circle hatch, but do at a 45° or 60° angle?
#81329 by dhs
Sun Aug 07, 2022 1:00 pm
could one do a similar effect using the existing circle hatch, but do at a 45° or 60° angle?

The existing hatch is at 60°. That and 90° are the only angles that will produce an even spacing. None-the-less, I have updated my spreadsheet to allow you to enter a vertical angle (each circle will be placed at the specified distance at that angle from the corresponding circle in the previous row, but the distance from the next circle in the previous row will be different for all angles other than 60°).
Updated spreadsheet is attached, and an example of 45° is shown below (you will notice that the row of circles from bottom left to top right is at 45°, but due to the closer spacing of the circles in the other direction the angle does not appear to be 45 at first look)
Circle45.png
Circle45.png (952 Bytes) Viewed 56 times
An angle of 90° does produce an even spacing:
Circle90.png
Circle90.png (982 Bytes) Viewed 55 times
Attachments
(34.6 KiB) Downloaded 10 times

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