# Creating flat patterns from projections

**URL:** <https://discourse.shapr3d.com/t/creating-flat-patterns-from-projections/28925>\
**Category:** Modeling Questions\
**Created:** [November 14, 2023, 2:59pm UTC](https://discourse.shapr3d.com/t/creating-flat-patterns-from-projections/28925 "2023-11-14T14:59:36Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Matteo](https://avatars.discourse-cdn.com/v4/letter/m/f9ae1b/32.png) [@Matteo](https://discourse.shapr3d.com/u/Matteo)\
**Post date:** [November 14, 2023, 2:59pm UTC](https://discourse.shapr3d.com/t/creating-flat-patterns-from-projections/28925/1 "2023-11-14T14:59:36Z")

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I am working on a Shapr 3D drawing, specifically related to 3D CAD design. The drawing you see represents the front and back of a chair’s backrest. It is made of flat

 ![Screenshot 2023-11-14 alle 15.46.43](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/3X/9/b/9b15092770bf0bce3e3c45c8f33467e60894f034.jpeg)  
 ![Screenshot 2023-11-14 alle 15.46.19](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/3X/7/0/70d1075259dc2720d61baaf945146b0f3bbc575f.jpeg)  
polyurethane, which is always processed into flat surfaces with a certain thickness. In this particular case, the flat figure resembles a trapezoid, with base A measuring 796 mm, base B measuring 360 mm, height measuring 576 mm, and a thickness of 30 mm.

However, when I create a 2D drawing, it does not reflect the development measurement of base A of 796 mm but rather that of the 2D view, which is 516 mm. I apologize for the convoluted wording, but I couldn’t find another way to explain it.

Therefore, I need to provide the foam fabricator with a 2D flat representation with the correct dimensions that should reflect the development of the curve.

How can I obtain the flat development of this figure with the correct dimensions?

Having the flat development of a figure is crucial in the manufacturing process.

Thank you for your assistance

 ![Screenshot 2023-11-14 alle 15.46.43](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/3X/9/b/9b15092770bf0bce3e3c45c8f33467e60894f034.jpeg)  
 ![Screenshot 2023-11-14 alle 15.46.19](https://us1.discourse-cdn.com/flex002/uploads/shapr3d/original/3X/7/0/70d1075259dc2720d61baaf945146b0f3bbc575f.jpeg)

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**Author:** ![Daniel\_Horvath](https://avatars.discourse-cdn.com/v4/letter/d/977dab/32.png) [@Daniel\_Horvath](https://discourse.shapr3d.com/u/Daniel_Horvath)\
**Post date:** [November 14, 2023, 3:37pm UTC](https://discourse.shapr3d.com/t/creating-flat-patterns-from-projections/28925/2 "2023-11-14T15:37:52Z")

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Hey @Matteo,  
2D drawing views are projected from the 3D object, the 516mm dimension is correct as this is the distance between the edges.  
The circumstance of the lower edge can not be represented in drawings, but you can use `Note tool` to annotate it. Please check my short video about it.  
You would need `sheet metal tool` to unfold the backrest of your chair modell and create unfolded 2D drawings, but unfortunately this is not available yet in Shapr3D

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**Author:** ![Matteo](https://avatars.discourse-cdn.com/v4/letter/m/f9ae1b/32.png) [@Matteo](https://discourse.shapr3d.com/u/Matteo)\
**Post date:** [November 14, 2023, 9:35pm UTC](https://discourse.shapr3d.com/t/creating-flat-patterns-from-projections/28925/3 "2023-11-14T21:35:26Z")

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Molte grazie Daniel  
Thanks a lot Daniel