intersection curve-curve/CCX problem

Hi all,

i'm trying to find the intersection points in the net of wires inside the shell of cooling tower. It's not the first time i find the CCX tool working against my assumptions. Maybe it is the bug or a matter of scale of precision. Does anyone know why CCX tool doesn't show all points of intersections on this model ? Thank You for any ideas on this topic.

greets

Adam

Attachments:

example.rar, 18 KB
example.bmp, 3.9 MB

Replies to This Discussion

Permalink Reply by Daniel Davis on November 11, 2010 at 4:33am

Hi Adam,

I don't know the precise workings of CCX, but it probably uses a tolerance to decide if the lines intersect, in this case the lines might not be quite intersecting. You might like to try this curve shatter-er: http://parametricmodel.com/Shatter2dpattern/9.html if you double click the C# script you can see the tolerance variable inside.

Daniel

Permalink Reply by Adam Chałupski on November 12, 2010 at 1:28am

Thank You Daniel,
it might be something with the tolerance but the shape is perfectly simetric therefor it is a bit weird why selected points form that funny shape.
I click on the link from you but after it i can see only code, there is nothing to download, then should i copy it and paste to C# node or it is something wrong with the page ?
It is very usefull tool and I realy like to have it on my libary !
cheers

Adam

Permalink Reply by Daniel Davis on November 12, 2010 at 5:37pm

Hi Adam,

The Grasshopper files look like HTML files and the browser was trying to open it as a web page. It updated the site to force the files to download, but if that does not work, try right-clicking and choosing 'save as'.

The tolerance in Rhino can be set really small, like 0.0001mm, so even rounding errors can cause lines to no longer intersect.

Daniel

Permalink Reply by Adam Chałupski on November 12, 2010 at 10:01pm

Daniel, it's great tool ! I think it's time for me to start learning C to be able to write scripts like for example that one.
I found the way to resolve my problem. It seems that rhino circles were somehow not enought precise. I draw them on GH and everything works perfect - with CCX and same with yr tool.
all best !

Adam

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