Concrete Hatching problems

[lem_102074329]

When using concrete hatch in Model space (Autocad 2002) in some drawings the small triangles formed as part of the concrete hatch don't join up correctly. So you end up with what looks like dashed lines going in every direction. I was talking to a workmate & he also mentioned he has this problem as well, his solutiuon is to take the object to be hatched into a seperate drawing that dosen't have this problem, hatch it & reinsert to his working drawing, which works quite well but I would like to clarify this problem as a opposed to avoiding it. Any help or ideas would be great.

[sinc]

I think this usually happens if you get a long ways away from the snapbase, which by default is (0,0,0). Try typing "snapbase" and selecting an area in the middle of your drawing, then reapply the hatching.

[Mike.Perry]

Hi

Just to confirm "richards.64879" answer, check out the following Technical Document on the Autodesk web site under the Knowledge Base section -

ID: TS60223 - Hatch patterns display incomplete or broken up (http://usa.autodesk.com/adsk/servlet/ps/item?siteID=123112&id=2880908&linkID=2475323)

Have a good one, Mike

[hugh.69031]

Hi,

The problem is a result of inadequate numerical precision in the pattern specification showing up at locations remote from the hatching origin. The pattern works fine up close to the hatching origin, which is why moving SNAPBASE or the UCS closer to the hatched area helps - fewer repetitions of the hatch pattern occur between the origin and the viewed pattern portion. Most hatch patterns lose registration on very extended repetition, some faster than others.

You can also fix the problem with a more precisely specified hatch pattern as an alternative to adjusting drawing limits or moving SNAPBASE to and fro.

Further information on this subject can be found here - www.cadro.com.au/hatchkit/ (http://www.cadro.com.au/hatchkit/)

Advertisement material *removed*, for further information please refer to the following -

Forum Don'ts (http://forums.augi.com/faq.php?faq=vb_augi#faq_vb_augi_donts)

<snip>
Do not post advertising or self promotional material or links to them to the Forum. We realize that there is a gray area where it may be necessary to do so to provide technical solutions. We also recognize blatant self promotion. To advertise on AUGI, please contact the Augiworld Magazine staff.
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Thanks, Mike (Forum Moderator)

regards,
Hugh Adamson

[hugh.69031]

Mike

please allow me to clarify that we do not offer more precisely specified hatch patterns for sale, so anybody following the results of your editing will be misled. I am sure that was not your intention.

The point I was making, in the portion you removed, was that the area of utility of any existting hatch pattern can be expanded to co-ordinates measured in the tens of millions.with HatchKit.


thank you,
Hugh Adamson

[Mike.Perry]

Hi Hugh

I hope you can understand why I *removed* the part I did, in it's original form I felt the post definitely crossed into that grey area.

I also honestly hope you realise this is nothing personal, it is just me (with Moderator hat on) trying to do the best I can.

My intention was not to mislead, I thought hard and long if I should have removed all references to "cadro.com" but decided that would be unfair and slightly unjust.

Therefore how would you like me to correct the "misleading" part or would you care to correct it yourself (I honestly don't mind)? Please bear in mind I won't restore the original content nor do I expect you to do so.

<add>
I've now slightly amended my edit, hopefully it's no longer "misleading".
</add>

Thanks for your understanding and support on this matter,

Mike

Forum Moderator

[lem_102074329]

Yeah thanks thats seems to do the trick. Since some drawings are closer to to the default snap base than others it makes sense that it only happens in some drawings not all.

Thanks again for your Help.

[hugh.69031]

That's ok, lem, happy to help. If you sit down with the hatch pattern specification and work through the geometry involved, you can see why some of the standard hatch patterns are more prone to this problem than others and why maintaining maximum precision in hatch pattern specification can avoid having to adopt other workarounds later.

Hugh Adamson
www.cadro.com.au (http://www.cadro.com.au)

[jyodak]

The original AR-CONC hatch pattern in AutoCAD was created back in 1988, I believe, in connection with Autodesk's then AEC product. Machines were slow (think 286 & 386), long hatch pattern definitions definitely slowed down drawing speed, so compressing the 30 odd line concrete hatch pattern definition down to its present 13 line size, and greatly increasing the randomization (certainly not perfect) was a big improvement. At the time, no one thought about hatching out to the boundaries of precision, sorry. Now with the ability in 2006 to respecify the origin for an existing hatch, this should be less of a problem.

[TWD_CW]

I have had the same problem for a couple of Releases (2002 to 2006) with some of the more complex patterns (GRAVEL, CONCRETE etc.)
With the enhanced hatch editing properties I've found if you default your hatch origin to the boundary extents (bottom left of the Hatch Edit dialogue box) you should find your problem solved.
Good luck

TWD