offset pattern with multiple attractors

I have a pattern that i want to cut it in laser cutter. I need to offset my lines for that. I would like the offset to depend on attractors. So i attach my file so that maybe someone can help me.

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Inside the file there are these notes:

i want to offset the lines so that they
can be cut by a laser cutter.
the offset command doesnt help me
though because it doesnt connect
the lines since i cant fillet, PLUS i want
to offset with multiple attractors.
So I though I could move the
start-end points in the direction
of the bisector of each vertex
that is formed by each pair of lines
and finish with a line command
as i did in the previous step
where i prepared the deformation
of the pattern.

I tried shift list command but i
see that its not right because
if i shift my list then its not sure
that gh will pick the
neighbouring line, so it could
connect random points
sometimes. I cant think how
to manage my lists or something
so that i take the bisector
each time from each vertex
in order to move each vertex
in the direction of the bisector
and then connect start-end points
with the line command.

Attachments:

PATTERN2.gh, 44 KB
PATTERN1.3dm, 457 KB

Replies to This Discussion

Permalink Reply by Arend on August 17, 2014 at 12:04pm

Can you submit an image / sketch / mockup of what you're trying to accomplish? I'm really sure I understand what you mean.

Permalink Reply by etsim on August 17, 2014 at 12:24pm

i printed it and started doing it with a pen so i hope it helps. I now realise that i dont need the offset of the lines but i need the offset of every "closed" shape in the drawing. Which Im not sure how to obtain.

Attachments:

DSC_0546.jpg, 951 KB

Permalink Reply by ng5 Alex on August 17, 2014 at 12:35pm

bowerbird has a nice polyline offset component you can try

http://www.grasshopper3d.com/group/bowerbird

cheers

alex

Permalink Reply by ng5 Alex on August 17, 2014 at 12:50pm

finding the closed shapes is the tricky part.

see these two threads that will help you

http://www.grasshopper3d.com/profiles/blogs/closed-curve-intersecti...

http://www.grasshopper3d.com/forum/topics/how-to-use-curves-finding...

alex

Permalink Reply by etsim on August 17, 2014 at 12:51pm

thanks for that alex, but as im working more on this thing, i realize that i have to find all the intersections and all the closed shapes that are generated and offset them. So it would be nice if there was a way to define all the closed shapes as polylines and then make an offset which would depend on attractors. so not a uniform offset.

I now used multiple curves intersection-tool... but im still thinking.

Attachments:

Capture.JPG, 215 KB

Permalink Reply by ng5 Alex on August 17, 2014 at 12:55pm

yes that is what david stasiuk's script is doing

http://www.grasshopper3d.com/profiles/blogs/closed-curve-intersecti...

Permalink Reply by ng5 Alex on August 17, 2014 at 1:01pm

Permalink Reply by Arend on August 17, 2014 at 5:18pm

Ok, that's easy.

Just grap the clipper plugin: http://www.food4rhino.com/project/clipper

In your case tweaking the tolerances makes it a bit faster:

Attachments:

PATTERN2-clipper.gh, 38 KB

Permalink Reply by etsim on August 18, 2014 at 12:14pm

I really want to thank you guys. Thank you alex and thank you arend.

Is there a way in Clipper that I can use multiple values for the distance? So that I can make the offset distance depend on attractors?

Permalink Reply by Arend on August 18, 2014 at 12:18pm

Yes, if it's per cell. You can use for example the from the center of the cell to the attractor points as an input for the offset distance.

Permalink Reply by etsim on August 18, 2014 at 1:17pm

Ok Arend thank you. I solved my problem. I only dont understand why i have to graft both the polyline input and the distance input, but that only just to understand it. Thank you.

Permalink Reply by Richard Haverland on December 17, 2017 at 11:04am

Hey Guys,

I have the same problem as etsim. I want to offset every line depending on the distance to an attractor. Somehow it is not working in my case.

I generated a maze and joined all lines, which belong to the same "corridor". Now i want every corridor to have a width depending on the distance to an attractor. I compared my definition with etsim's and Arend's to find the bug in mine. Compared with your definition, i get just a contour output, but not a holes output. I guess this is the reason why my offset is not working correctly. So do you guys have any idea, why there is an empty output in holes? Although this i an old article, i hope you recognize it. :)

Greetings, Richard.

Attachments: