Tube bending made 2D


I am working on a bend tubular chair frame. The company which will prototype this using cnc bending doesn’t work with 3D files and requests 2D drawings. I have made such drawings before, they include radii, angle, rotation and lenght and take me a lot of time to make. I need to make plenty of guidelines to be able to calculate the various angles. All dimensions are not perpendicular to the views so I use leaders to be able to dimension it.

There are plugins for packages such as Solidworks which automate this process. (BendTech, AdvancedTubular).

Does anyone know a way an easier way how to make these 2D drawings? Or a plugin? Preferably with a bend table.


ps. Working on Rhino Mac but posting this here since the Mac doesn’t support plugins yet. If someone knows a solution for Rhino Mac that would be great.

Hi Niels,

There are no plugins that I am aware of (someone else might know one however)
Yet it is possible to at least create some scripts to make your work easier.
Breaking a 3D curve down in sections and annotate the lengths, radii, angles and such can partially be automated.
Maybe someone over here has some scripts laying around and if you are in need of this type of scripts often
it might be worth to invest some time and/or money to have these scripts made for you.


Hrmm scripting? Well, unfortunately in my case it will still be faster to just draw it. I tried to get python to work on RhinoMac, but somehow never got it to work. Yet…

Since the bends are on different planes I am making the drawing in ortographic view. For the various bending stages I am lining up the cPlane with the object and dimension it from there on for that bending step.

When I am exporting the drawing to .Ai it only exports the dimensions for the active cPlane. Is there a work around for this so I can export all dimensions at once?

Found a solution for this. At dimension styles set text horizontal to view. Explode all dimensions you’d like to export. Align the cPlane with view, or the plane of the text object. Text objects get exported properly, leader tips are open but can be hatched in Rhino or closed in illustrator.

Unless I am overlooking something, it would be a nice feature to be able to dimension in perspective view and export dimensions, even though they don’t line up with the cPlane. The reason for dimensioning in perspective view is because most angles, radii, distances of more complex shapes get modified by projecting it with Make2D.
Hope this can be helpful.

If tube bending is not your daily work to do, making a drawing by hand is ok. Tube bending can be sorted into two main categaries. One is fixed radius bending, the other is tube rolling, the radius is not fixed, and normally is bigger than 10x the OD of the tube.
Fixed radius tube bending is easy to handle, you just provide the end point and the intersection point xyz data in the right order and specify the radius. The tube can be reverse engineered and converted to LRA data, that most CNC bending machine can read.
For tube rolling, or tube with rolling and bending you’d better provide a detailed drawing with all the dimensions labeled and the 3D drawing. My understanding is that a tube bending factory should have no problem handling 3D drawings. Or ask them for a templete on how a tube should be dimensioned in their convention.