[Plugin] WireTool (Catenary) (1.4.1) – updated 06.03.2013

Aerilius

Tools normally don't have weird behavior without reason. Running it with the Ruby console open gives often more definable results.
So I found and fixed an unobvious bug with the translations that stirred up all methods and I changed that the x-width of segments is variable to give always the same segment length.

Michaelv

Great Thanks.

There was another catenary tool (and other geometric curves too) here:
http://forums.sketchucation.com/viewtopic.php?t=41310

I needed to make them like this though.

See below however, the first segment is much longer and they become smaller as they go on the curve:

Aerilius

@Michaelv: Thanks for noticing this! It was not much visible with little sagging (110%) but with big sagging. Sorry that it took some time (it's not easy to do math with curve lengths).
I fixed it now.

I also thought about the problem and find that the corners/endpoints a even less noticeable when I use equal angles between the segments. If you prefer equal segment lengths, you can change the parameter @@segments_distribution_mode to 1 inside the script.

Michaelv

Thanks!

A nice option (but I can do it when I get a minute) would be for the start to start either like you did (wire) or horizontal )like a cable that's more rigid, yet supported by posts.
Toggle with alt/option

I think all it takes is force the angle at point of attachment to be horizontal, and the equation would take care of the rest. But maybe not.
Never mind, I looked at it and the equation as it stands is for tension always parallel to the tangent of the curve, thus deflection equations (with rigidity, etc..) at the boundary would have to be used until that is the case. too complicated for the time being.

Danke Shoen!

moluasa

Might also be cool to work with for line art!

Aerilius

Minor update (1.4.0):

converted it into a SketchUp Extension (that you can turn on/off)
added icons and cursor
Please remove older version if you update.

Oxer

Thanks for the update!!
This is the spanish language:
%(#FF0000)["es" => {
"Draw Wires" => "Dibujar Cables",
"Catenary" => "Catenaria",
"Tool to draw catenary curves." => "Herramienta para dibujar curvas catenarias."
"Arc Length" => "Longitud Arco",
"Segments" => "Segmentos",
"Distance" => "Distancia",
"Select first end" => "Selecciona Primer Final",
"Select second end" => "Selecciona Segundo Final"
},]
You can to include in the next version.

EDIT: On Mac the icon doesn't show but I have added the line below in the end of the WireTool.rb file and now it shows:

   %(#FF0000)[UI::Toolbar.new(@@translate["Draw Wires"]).add_item(cmd)]

Aerilius

Thanks!

gilles

I notice that you specify a length you always got a approximation, not the desired length.

Aerilius

That has two reasons: SketchUp has no curves and like arcs, the length of these catenary curves isn't the sum of the segments.
The other reason is that the numerical algorithm needs many many more iterations to reduce the bulge if the curve is almost straight (100% should theoretically give a straight line). I'm working on improving this.

gilles

Good work by the way, a useful one.

Aerilius

Just to give you an idea: I increased the number of iterations (at every mouse move) from 10 to 150 and the overlength is still half of what it was before (and 150 iterations is far too much). But at least I know which part to optimize.

Bob James

@aerilius said:

Minor update (1.4.0):- added icons and cursor

I don't see "draw wires" in my toolbar list

TIG

@bob james said:

@aerilius said:

Minor update (1.4.0):- added icons and cursor

I don't see "draw wires" in my toolbar list

Did you first activate its Extension under Preferences ?

Aerilius

I've uploaded a new version 1.4.1 improving the 100% curve length issue (curve was too long).

The previous version didn't mention any toolbar (only icon image), though as it seems nobody else has a problem with one-button toolbars I added one . I hope it doesn't increase the toolbar mess.

Oxer

Thanks Aerilius!!
I have saw that you have included the line for the Toolbar and spanish language, thanks again.

irwanwr

Thank you very much for this plugin.

slander

Thanks very much for this. It produces a really lovely result for drawing thin arches.
I noticed a small problem when I move the endpoints of an existing catenary around - gravity seems to veer away at an peculiar angle. All plan-plane moves seem to work just fine though.

Aerilius

Hi,
the resulting curve is just SketchUp geometry, and does not expose physical behavior of a wire. When moving one end point of an arc, it shows normal SketchUp behavior (ie. SketchUp tries to squeeze or stretch the arc to fit to both end points).
But a wire that really (physically) moves with attached objects would be a cool feature. The plugin would need observers to watch all the time on all these arcs, and recalculate an arc once an endpoint is changed.

Ben Ritter

I cannot get the plugin to work with specific inputs. It creates a the same curve no matter what I enter.

Can you help?