Extracting dimensional data from pdfs?

**Mark Petersen** · #1 01-17-2010, 03:50 PM

As I am working on the 1/48th Saturn V I find that in order to get consistently clean builds of the F-1s and J-2s I am going to need to build some fixturing for engine bells and such.* Does anyone know a good way to extract the data from the 2d pdf so as to be able to reconstruct the truncated cones that make up the engine bell assemblies? All I really need to get is the length of the arcs that make up the bell assemblies. From that I can find the diameters and angular taper of the cones. I have access to CAD and am trying out Rhino at home. I also realize that this can open up a can of worms in regards to pirating designs.

*Yah I know it's over-engineering the problem but it's the way I am

**sgoti** · #2 01-17-2010, 10:18 PM

It's funny you should ask this. I just found the formula for determining truncated cone patters last week (after a not-so-quick search).

Go to this page

Near the middle is a link for an Excel spreadsheet that will show the inner radius, outer radius, and arc angle for building a truncated cone of specified height and diameter(s).

Glenn

**SCEtoAUX** · #3 01-18-2010, 07:50 AM

Here is a calculator that might help in making truncated cones (frustums).
Cone and truncated cone

If you can't find a mathematical formula to find the length of the arcs some string and a ruler always helps. That is what I use most of the time.

**Mark Petersen** · #4 01-18-2010, 07:33 PM

Well, I allready knew about this ConeLayout - Product. What I really need to be able to do is extract the lengths of the arcs and lines from the image on the pdf file. I know at work with full blown acrobat they can do this IIRC. But I don't have that on my machine at work.

**sgoti** · #5 01-18-2010, 08:10 PM

Quote:

Originally Posted by SCEtoAUX

Here is a calculator that might help in making truncated cones (frustums).
Cone and truncated cone

Thanks for the link- Even better than what I found!

Glenn

**looker** · #6 01-19-2010, 05:16 AM

Have you tried using screen capture or conversion with Ghostscript/Ghostview to give a bitmap you can import into CAD as a background and then measure over?

**rickstef** · #7 01-19-2010, 07:40 AM

Mark, it sounds like you are using the reader version and not the full version, i know in the full version you can do what you are asking about.

Maybe asking those who have it to help you out

**B-Manic** · #8 01-19-2010, 02:46 PM

Quote:

Originally Posted by looker

Have you tried using screen capture or conversion with Ghostscript/Ghostview to give a bitmap you can import into CAD as a background and then measure over?

If the drawing in the pdf file is vector based Ghostscript/Ghostview can export it in vector format.

**lancer525** · #9 01-19-2010, 03:17 PM

There is a MUCH easier method of generating truncated and non-truncated cones, and it's free on top of that. It's called "Siatki" and you can find the free version on Gremir's page, the link to which is on my home computer, and I happen to be stuck at the office.

Does cones, spheres, cylinders, and the like, and it's really good. The pay version does more things, like toroids, and user-generated shapes as well. Great program.

**Mark Petersen** · #10 01-19-2010, 04:16 PM

Looks like I'm stuck importing a screen shot into AutoCAD and tracing the image on another layer. Tedious but it will work. Once I find the arc and line lengths I can reconstruct the conic section. That gives me the angle of the cone which is what I am really after. I was wondering if there was an easier way to work around the problem. That's why sometimes I wish the designers would release work in another file format. I understand the pirating issues but it would make it easier for the people who do re-colors and such for themselves