Real world accuracy in unwrapping?

I am beginning a new project and am running across something I’ve never even thought about in Blender.

The project is going to be 3D printing a model and then covering that model in carbon fiber fabric.

It occurred to me that I could simply unwrap the model in Blender, scale to real world dimensions, and print the JPG image to a large plotting printer. Then, just like a sewing pattern, I could lay this over my carbon fiber fabric and cut out only what I need.

I’m not the greatest texture artist, and didn’t really know: is it possible to get accurate, “real world” dimensions when unwrapping an object?

You’re probably better off checking paper model related addons and other programs
http://wiki.blender.org/index.php/Extensions:2.6/Py/Scripts/Import-Export/Paper_Model
http://www.tamasoft.co.jp/pepakura-en/

But not sure what kind of accuracy could be expected. We are dealing with polygonal modeling which is just an approximation of curves and surfaces and CF material might need some extra to have enough of it when it’s bent or forced to shape without a seam.

Ja-
Good idea. Looking for a rough approximation, as there will always be extra fabric around the seams for good overlap. The sheets are only .012 thick, so a little overlap here and there is OK. Should be very interesting. Thanks for the suggestions!

Hi, I own a costume company and have been using Blender for 2 years now to fabricate props and costume shapes. It’s pretty easy once you get used to it. Model your object, using low poly topology, keeping in mind to model your face loops where you think the real world sheets of material will be used. In other words, construct the object the way you think it should be fabricated using your sheet material. Be sure that each face loop is only 1 face wide. Mark your seams along your predetermined paths. Be sure to apply scale to your object before unwrapping. To be very safe I triangulate faces at this point. Unwrap. Use the Stretch checkbox in the N properties panel of the UV/Image Editor to confirm that it looks unstretched. Export UV map as .eps file (I use a fill strength of 0). Then open the .eps in Illustrator or Inkscape. Here’s the tricky part: Measure one of your model’s longest edges using the Mesh Display/Edge Info: Length menu item in the N properties window, and scale up (or down) all your vector objects in Illustrator/Inkscape program by the correct ratio to make that edge the right length. Overall, make sure you know which piece is which (maybe by labelling) and which way to orient it. Then nest the pieces to minimize print size, and tile the print job onto regular paper or send to a large format print shop for your patterns.

This has worked flawlessly for me for about a hundred objects so far. I can even take into account the thickness of my real world material (I work with foams ranging in thickness from 1/4" to 2 1/4") using the Solidify modifier with the Thickness set to my material’s and the Offset set to 0 (since the outside of my foam stretches by the same amount as the inside surface contracts).

Let me know if I can be of any more help, since I’m very enthusiastic about this application of Blender and am always looking for ways to put it to further practical use.