# reconstruct a 3D cylinder from a 2D image

I would like to reconstruct a cylinder from a 2D image of one.

Assuming a cylinder was sat on its flat end, viewed from the side it would appear to be a rectangle. If all you had was an image of that rectangle and the diameter of the cylinder, I believe there should be a relatively simple way to tell a computer that the image you have is of a cylinder, and then have it project that 2D image into a 3D model.

Unfortunately I'm struggling to work out what that method could be. Does such a program exist?

• Many technical drawings will make such assumptions: if there are no more views, then you can consider that you have all information required to build the thing. – Thomas Weller Jan 19 at 12:46
• There are some open questions: a) cylinders only? if so, it might be simpler to just model the cylinder yourself. b) do you have the diameter as a number? c) does the image show a side view only so that the image gives a rectangle? d) price? e) OS? – Thomas Weller Jan 19 at 12:48
• @ThomasWeller Thanks for the helpful comments. a) In this case yes, just a cylinder. I am trying to produce a 3D model (to be viewed virtually) of a cylindrical object. b) yes, the diameter is known. c) Yes side view only, so I am starting with the rectangle. d) preferably free e) Windows. Of course, I can do it by hand, but would like to automate the process. – missingsector Jan 19 at 14:38

If you have a rectangle and know the true representation is a cylinder, any program which can perform a revolve feature will provide the desired result.

Fusion 360 will do so, beginning with a sketch of the rectangle. Onshape performs a similar task just as easily.

Even OpenSCAD will allow a text representation:

``````height = 50;
diameter = 20;
rotate_extrude()
square([diameter / 2, height]);
``````

Note that in the code above, the diameter has to be divided by two, as typical revolve operations will require an axis reference. OpenSCAD reference is the origin and the rectangle edge lies at the origin. A minor factor overall.

The three programs noted above are free (Fusion 360 for hobbyist use) and run in windows.