This article describes the issue that can cause a drawing to include a flattened drawing view, where the sheet metal part is not flat.
Sheet metal parts can be flattened using the sheet metal Flatten feature or by unsuppressing the Flat Pattern features under the Flat-Pattern folder in the feature manager tree. The Flatten Feature can be found in the Sheet Metal Standard Toolbar (Image Below).
The Flat Pattern Feature can be unsuppressed by right clicking on the Flat Pattern Feature found under the Flat Patter folder in the feature manager tree and selecting the unsuppress icon (Image Below).
In drawing files, a flat pattern of a sheet metal part can be included using the view palette, which manually creates a derived configuration of the flat pattern in the part file. However, some users find that this flat pattern drawing view is not flat. An example is shown below.
This issue can be seen, if somehow in the derived configuration, the flat pattern feature was suppressed. The flat pattern derived configuration should always be flattened and other features should be edited in the default configuration. To resolve this issue, one needs to right click on the drawing view, and select open part. Once the part is opened, make sure you are in the correct derived configuration. Then flatten the sheet metal part by either selecting the Flatten Feature, or unsuppressing the flatten features in the feature manager tree.