This JTB Catenary app for AutoCAD makes it easy to create or draw a catenary curve as a polyline by specifying the start and end point and the length and optionally a diameter (width) or sag. This can be useful for drawing freely hanging cable, hose, chain, transmission line, anchor line (anchor rode), cord, rope, string, suspension bridge cable, arch, hawser, wire or the like.

The current version is creating a catenary line using the catenary formula y = cosh(x) = (e^x + e^-x)/2 and numeric analysis that results in a good enough curve for many purposes. The program does not take into account the tension of an elastic catenary, weight and so on. Support for this can be added based on user requests.

A parabola is different from a catenary. The catenary is the solution to a differential equation that describes a shape that directs the force of its own weight along its own curve, so that, if hanging, it is pulled into that shape, and, if standing upright, it can support itself. The parabola does not have the same property.

Catenary described according to Wikipedia:

In physics and geometry, the catenary is the curve that an idealized hanging chain or cable assumes under its own weight when supported only at its ends. The curve has a U-like shape, superficially similar in appearance to a parabola (though mathematically quite different). It also appears in the design of certain types of arches and as a cross section of the catenoid -- the shape assumed by a soap film bounded by two parallel circular rings.
The catenary is also called the "alysoid", "chainette", or, particularly in the material sciences, "funicular".
Mathematically, the catenary curve is the graph of the hyperbolic cosine function. The surface of revolution of the catenary curve, the catenoid, is a minimal surface, and is the only minimal surface of revolution other than the plane. The mathematical properties of the catenary curve were first studied by Robert Hooke in the 1670s, and its equation was derived by Leibniz, Huygens and Johann Bernoulli in 1691.
Catenaries and related curves appear in architecture and engineering, in the design of bridges and arches. A sufficiently heavy anchor chain will form a catenary curve.
Most suspension bridge cables like the Golden Gate Bridge follow a parabolic, not a catenary curve, due to the weight of the roadway being much greater than that of the cable.

JTB Catenary is available as an AutoCAD app on the Plug-ins or Add-ins tab.

JTB Catenary trial is available as an AutoCAD app on Autodesk App Store.

Limitation of trial is that the length is fixed to 10 meters. When purchased it can be used without restrictions.

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## System requirements

Compatible with those operating systems AutoCAD runs on like Windows Vista, Windows 7, Windows 8, Windows 8.1 and Windows 10.

Older Windows versions might also work but are not directly supported.

JTB World is an Autodesk Authorised Developer

## Purchase

30 USD for one license or less depending on the amount of licenses.

Purchase JTB Catenary from the Autodesk App Store site.

If you have really many users that you want to give access to this software we can discuss a discounted price based on your particular situation. Educational discounts available.

The license is perpetual and support is included. If you have more than one computer and you are the only user of the application one license is enough.

Available payment methods depending on country where payment is done from: Local Bank Transfer (Canada), Wire Transfer to Canada, Interac e-Transfer, Cheque (to Canada). Via BlueSnap (Global Payment Gateway) these methods may be available (not a complete list as it is updated from time to time by BlueSnap): Credit card (Visa, Master Card, American Express, Discover, Diners Club, JCB, Carte Bleue), PayPal, Local Bank Transfer, Wire Transfer, Real-time Bank Transfer, Electronic Check (ECP), Apple Pay, Skrill (Moneybookers), WebMoney, SEPA (Single Euro Payments Area) Direct Debit, Sofort, Giropay, iDeal and Alipay (SEPA (Single Euro Payments Area) Direct Debit, PaySafeCard, Ukash, cashU, Boleto Bancario, Boleto Bancario can be made available upon request) - Refund policy

## Documentation

### Installation

Use the AutoCAD app installer that also puts a button on the Plug-Ins or Add-ins Ribbon tab.

### Usage

The command to start the program is JTBCatenary (JC for short).

The program prompts are:
Start point:
End point:
Enter Length [Length/Sag] <10000>:
Diameter <0.0>:

Note that the length must be longer than the distance between the start and end points.

The resulting catenary will be created in the current drawing (DWG or DXF) as a polyline with the width being the same as the diameter.

Below the catenary has been created with a distance of 1000 between start and end and a sag of 100 has been specified, creating a true catenary curve with the length of 1026.

## Version History

• 2017-03-21 - version 2.0 update
• 2016-03-22 - version 2.0 update
• 2015-09-01 - version 2.0
• Added the ability to specify sag.
• 2015-03-20 - version 1.0 update
Digital signing of vlx and installer added
• 2014-04-03 - version 1.0
• Updated installer for the Autodesk App version to support AutoCAD 2015 and verticals.
• 2013-10-17 - version 1.0
• 2012-11-05 - version 1.0
• First public release

The license agreement is found here.

## Customers

ArtFX Events

Basic Machinery Co.

BRG, Inc

Centrais Elétrica S.A.

CEPS, a.s.

General Machine corp.

JIMAZ prodej sw s.r.o.

Ok Tedi Mining Limited

Parameter Design Engineering Ltd

University of Queensland

Woodhouse Tinucci Architects