topic Re: How convert this in .pat Hatch? in AutoCAD Forum

How convert this in .pat Hatch?

Leonardo_Czuy — Wed, 06 Mar 2024 19:08:59 GMT

Hello for everyone.

I waste 3 hours trying to create a .pat hatch for this.
I just get this lines, but they dont sync,

153.597198, 37.421, 0, -10, -5, 11.16441951, -50
26.402802, 42.421, 0, 10, 5, 11.16441951, -50

Re: How convert this in .pat Hatch?

Kent1Cooper — Wed, 06 Mar 2024 20:25:17 GMT

First obvious thing to me: The last two numbers in each line are pen-down and pen-up [gap] lengths, so they should be the length of the segment and the [negative] length of the gap to the next pen-down, like:

.... 10.90905365,-2.99315558

Since especially the last one -- a 50-unit gap when the lines are only about 11 units long? -- is so different from the actual size of the gaps, maybe you just need to study the way they're defined in more detail. It takes some getting used to, but this is not so complex a pattern that you couldn't figure it out. I and others here could work it out, but I would also want to know such things as where the origin point from which it is generated should be: the middle of a diamond? the middle of an "aisle" intersection? a corner of a diamond [and which one]?

The pattern would require four lines of definition -- one for the "top" edge of each diamond at each of the two angles, and another for the "bottom" of each at each angle.

[And I'm curious -- where are the sizes and spacings coming from? The only thing that makes some sense seems to be the width of the "aisles" at 2.5 units, but everything else, distances as well as angles, seems to be out-of-nowhere wacky numbers.]

Re: How convert this in .pat Hatch?

Michiel.Valcke — Thu, 07 Mar 2024 08:47:22 GMT

To make custom hatch patterns I always use this handy lisp:

Re: How convert this in .pat Hatch?

Kent1Cooper — Thu, 07 Mar 2024 21:50:11 GMT

@Michiel.Valcke wrote:

To make custom hatch patterns I always use this handy lisp: HatchMaker.lsp

I would be interested in seeing what HatchMaker does with that. Conveniently, two "bays" of the pattern do fit in a square, but since HatchMaker wants it drawn to 0.01-unit snap increments and in a 1-unit square, I would guess that the diagonal lines don't work out to be truly collinear, which I think means what look like line sets with gaps are probably not done in one lineset, so more lines of pattern definition are required than what it could be done with. And of course it can't be defined at the drawn scale with the "aisles" being 2.5 units wide if the whole two bays of pattern are forced into a 1-unit square, so it would probably need to be used at some strange scale factor to get a given "aisle" width. But maybe that's acceptable.

Re: How convert this in .pat Hatch?

Kent1Cooper — Fri, 08 Mar 2024 18:52:24 GMT

@Kent1Cooper wrote:
....I would be interested in seeing what HatchMaker does with that. ....

So I tried it. I did some regularizing [in the original drawing the lines that look like they should be collinear are not really, and the diamonds are not actually the same size], and it made something that's pretty good but has a few segments missing:

I found one pen-up number different from all the rest, and changed it to match, and that fixed it. But it needs to be used at a scale of a little over 25 to pretty nearly match the original drawing. And it does use 16 lines of definition, when it could be done with four. I could make that happen, and at the actual size of the original drawing elements with some fixing for collinearity, but how important is the size? And the "aisle" widths relative to the size of the diamonds? The lengths of the diamond edges? The 1:2 slope of the lines? Or whatever the critical criteria are, if any....

Re: How convert this in .pat Hatch?

Leonardo_Czuy — Fri, 08 Mar 2024 18:53:53 GMT

@Kent1Cooper
Really Thanks for Helping.

I did this and work well.

*DIAMOND-PATTERNED
153.434949, 0, 0, 8.45820397, 11.27760524, 11.18033989, -2.91666667
153.434949, 10, 5, 8.45820397, 11.27760524, 11.18033989, -2.91666667
26.565051, 0, 0, -8.45820496, 11.27760491, 11.18033989, -2.91666667
26.565051, -10, 5, -8.45820496, 11.27760491, 11.18033989, -2.91666667