Hatch with Array of Circles

[gregmorris234]

Hi All!

 

Would anyone happen to have a Tactile Paving Block Hatch?

 

I have managed to create one that gives me the correct block dimensions but I can't seem to get very far with one with the circles. I understand that arcs and circles don't work on hatches so you have to make it work with line segments but I still couldn't get anywhere. At the moment I'm just going to use a preset block and SuperHatch but it would be really good to get a PAT file. The attached image shows what I'm trying to achieve. Note there is a 1mm spacing between the blocks.

 

 

I tried making it work with the Hatch Maker LISP but that came out with some dodgy results where it deleted a lot of the circle segments and I couldn't make it seamless when constrained to a 1x1 box. 

 

I thank you in advance! 

[steven-g]

It is difficult to explain but yes a hatch pattern has to be made of straight line segments that repeat in a pattern, but because of the angles and distances involved it is difficult to achieve a true circular shape (one that has many edges) for a random distance between 'circles' so you end up with a pattern that doesn't really look convincing as a circle it might only have 6 or 8 sides. For something like your image then an array or even a dynamic block would be a much more suitable method, even if it means then exploding the array and deleting stray objects as a secondary step.

[BIGAL]

Have a look at this solution Marko has put a lot of effort into it.

 

For the circles use a polygon to create multi lines. Say 10 sides, at the scale of a tactile you could try a smaller value like 6.

 

 

[eldon]

With the circles, I started with a 12 sided polygon, a dodecagon. I had to tweak a line or two because they were not pointing in the useful direction. I have always wondered how these automatic pattern file programmes cope with small inconsistencies. All my circle lines touch!

 

Anyway, I wrote a pattern file. It was very useful having dimensions to work to.

 

*TactilePaving, Tactile paving slabs
0,0,0,0,268,200,-1
0,0,133,0,268,200,-1
0,67,134,0,268,200,-1
0,67,267,0,268,200,-1
90,0,0,0,201,133,-135
90,-1,0,0,201,133,-135
90,66,134,0,201,133,-135
90,67,134,0,201,133,-135
14.931417,27.444149,42.626587,763.905343,4.315849,5.75,-1034.369705
14.931417,33,21.891853,763.905343,4.315849,5.75,-1034.369705
75.068583,21.891853,33,763.905343,-4.315849,5.75,-1034.369705
104.931417,23.373413,27.444149,763.905343,4.315849,5.75,-1034.369705
284.931417,42.626587,38.555851,763.905343,4.315849,5.75,-1034.369705
345.068583,33,44.108147,763.905343,-4.315849,5.75,-1034.369705
255.068583,44.108147,33,763.905343,-4.315849,5.75,-1034.369705
165.068583,33,21.891853,763.905343,-4.315849,5.75,-1034.369705
45,23.3733416,38.555851,47.376154,47.376154,5.75689,-88.995419
45,38.555851,23.373413,47.376154,47.376154,5.75689,-88.995419
315,38.555851,42.626587,47.376154,47.376154,5.75689,-88.995419
315,23.373413,27.444149,47.376154,47.376154,5.75689,-88.995419
*eldon fecit MMXX - CADTutor forum

 

Save the above file as TactilePaving.pat and put it where AutoCAD can find it.

 

Also I have attached the file itself and a picture.

 

 

TactilePaving.pat

[gregmorris234]

Ah guys, you never let me down. Thank you so so much for this and the links to the other posts for guidance.

 

Just so I understand it more. The first 9 lines are the repeating pattern of the blocks themselves yes? Then after that I guess is the lines that make up the circle? (12 lines of code, 12 sides of the dodecagon). To get all the coordinates and angles etc. did you use the Hatch Maker Lisp or some other method?

 

I think when I saw all those non round numbers I panicked and thought there was no way I could make sense of it but I think I finally understand how this works and it's all thanks to the kind users of CADTutor - Thanks again guys.

 

 

 

[eldon]

When one starts with pattern definition files and see all the figures, it can be alarming! But each line is limited to 80 characters, and if there is any opportunity to use exact numbers (with fewer than two decimal places) then that saves the number of characters. It is necessary to make use of all those decimal places when the hatch is a long way from the origin otherwise the lines split apart (as you have seen).

 

I do not use any artificial help, but prefer to manually follow the pattern of the definition file (as pictured below). If you draw every thing out it is not hard to pick up all the information to make the hatch file.

 

The first 8 lines, those beginning with 0 or 90 are the block outlines, drawn starting at 0,0.

 

The next 12 lines are the circles. First of all, i drew a 12 sided polygon, and copied it to form the hatch pattern. Using a circle of radius 11, I drew an inscribed and a circumscribed 12 sided polygon, measured the lengths of both, and then decided to use a side length of 5.75 (cutting down on the number of decimal places). Then I projected one of the lines to see where it hit another circle. It doesn't actually hit one, but 15 rows over it nearly hits one. So I altered the angle from 15° to 14.931417°, not a lot, but enough to make the lines to be in line. Then I redrew the polygon using the new angle, and drew the dash line. I then offset this through similar points on the shapes until a pattern emerged from which I can measure the sideways repeat lengths. Then I worked my way around the shape, picking the lengths and angles from the working drawing. Simple!

 

Finally, at the end of the file, I have found that if there is an asterisk at the start of the end line followed by comments, one does not have to leave a blank line at the end of the file.

 

 

[BIGAL]

Interesting having to work with tactiles in roads rather than true "TILES" we did not use tiles any more to many problems with them cracking and lifting, instead went to a plastic strip which has buttons on top, the contractor uses a concrete saw and the strip is hammered in till buttons are flush. 

 

The Australian std for tactiles refers to color difference of the buttons to the back ground, so concrete was black, asphalt was yellow. The testing method was interesting as a special camera had to be used to make sure buttons were correct color, oh yeah 1 camera in Australia. 

 

http://www.blindaid.com.au/tactiles.html

Edited November 19, 2020 by BIGAL

[eldon]

Not having had much practice with circles in hatch patterns, I thought I would try to use a 32 sided polygon (a triacontadigon) in the hatch pattern and see how much accuracy I could get. This makes a difference when the hatch is a long way from 0,0.

 

Examining the format of the hatch pattern definition, there are angles, coordinates and distances. When one moves far from 0,0 accuracy of the angles is important because the effect is magnified and so are the distances. The coordinate is only the start point of the hatch pattern and thus can be less accurately defined (3 decimal places). One needs to aim for 10 decimal places for angles and distances, but also bearing in mind that the maximum length of a single line of definition is 80 characters.

 

Because AutoCAD can only display angles to 8 decimal places, I thought to improve that accuracy by trigonometry. When one tweaks the direction of each side of the polygon to aim at the next pattern shape, the tangent of angles can always be defined by integer values. So too the distances. Thus with a spread sheet, one can calculate angles and distances more accurately then AutoCAD can display them.

 

I managed to rewrite the Tactile Paving hatch pattern with a 32 sided circle with as many decimal places that I could and called it TactilePaving32.pat. As this was a bit of a trial for me, I will not be posting the actual definition file unless someone can't live without it!

 

The picture below shows some hatches a long way from the origin (coordinates shown) of the two hatch patterns - TactilePaving and TectilePaving32. One can see how less accurate my first hatch pattern was (bits of line spread out all over the place), but as long as it is used close to the origin, it should suffice. But the latest file TactilePaving32 shows almost no separation of the hatch elements.

 

 

[BIGAL]

AR-Conc pattern displays this problem all the time as often would be at co-ords like 5000000,257000 so resetting origin point from properties or when creating fixes problem.

 

Would that fix TactilePaving.pat once created ?

[eldon]

17 hours ago, BIGAL said:

.......Would that fix TactilePaving.pat once created ?

 

A complete rewrite using more accurate angles and distances. I am learning all the time, and that was a first effort where I tried to pick angles and distances from an AutoCAD drawing.

 

17 hours ago, BIGAL said:

AR-Conc pattern displays this problem all the time as often would be at co-ords like 5000000,257000 so resetting origin point from properties or when creating fixes problem.

 

If you look at the pattern file of AR-Conc, there do not seem to many figures after the decimal point. It consists of three triangles and four dots, all going at different angles, thus giving a random appearance. Very clever, but best used close to the origin!

[eldon]

Having raised the question of AR-CONC not being very good at large coordinates, I thought I would look at it and start a new thread.