Unbending

This command allows you to locally unfold a (or several) bend(s), in order to remove the bend and if required in the neighboring faces, then to rebend it.

Creation stages / Use:

Click the icon or select Sheet Metal > Unbending... from the drop-down menu.

Select a fixed edge of the sheet.
Select faces of the bend(s) to unbend.
Validate the creation of the unbending operation with the button.

Select a bend by clicking on a cylindrical face of the bend.

Available Options:

The All bends option automatically unbends all the bends of the part. This mode is associative, if a modification after the creation of the unbending operation generates a bend, this bend will automatically be unbent.

Unbending of Bend:

Three unbending modes are available:

Bend: This option allows you to unbend one or several simple bends.
- Fixed edge: It allows you to determine an edge on the fixed side of the part. The edge can be connected or not to the selected bend.
- Bend faces: This list allows you to choose the bends to unbend. It is possible to select only one face per bend (internal or external).
- All bends: this option allows you to unbend all the bends on the part.
Bend with deformations: The selected bend faces are unbended with the chosen unbending method. The forming faces connected to these bend faces are deformed following the bend unbending transformation.
- Fixed edge: It allows you to determine the fixed edge of the part. The edge can be connected or not to the selected bend.
- Bend faces: Only one bend can be unbended at a time (or a set of aligned bends). By default, when selecting a bend face, its opposite face is added, as well as the bend faces aligned thereto.
  
  Bend faces to unbend selection.
  
  Aligned bend faces with deformations.

Forming faces: It allows you to select the forming faces to consider. It must be connected to the bend.

	The chosen faces must be included in the "pie chart" of the bend. This one must be correctly delimited before launching the command. An automatic selection is proposed after selected the bend. This selection can then be refined by adding or removing deformed faces.
Selection of forming faces connected to the bend to unbend.

Developable bend: The selected bend faces are unrolled with the chosen unrolling method.
- Fixed edge: It allows you to determine the fixed edge of the part. The edge can be connected or not to the selected bend.
- Bend faces: A selection filter allows you to select only strictly developable faces, excluding cylindrical faces (which must be processed in Bend mode).
that are unroll with the Developable bend option.

Unbending method:

Refer to the unfolding rules command for more details.

Corners relief:

This option (only available in Bend mode) allows you to add corners relief on the unbending at the intersection of the center of the unbending bends. It allows to modify on parts coming from import and conversion to sheet metal to enable their industrialization punching.

Only neighboring bends connected to the same base surface will be considered.

Corners relief type / Dimensions:

Select the corner relief type to use (spherical or cubical) and its dimension.

Extract on unfolding:

Created corners relief can be extracted on the unfolding to have straight edges.

Example of unbending of bend with corners relief

Advanced options:

Allow surface result:

When reconstruction problem of the lateral faces of rebent bends is detected, the sheet is then invalid. This option allows a valid sheet to be achieved nevertheless but the result will be on the surface.

Without bend lateral face:

In some complex cases, this option allows to ignore the lateral faces rebuild steps which can be complex and which can failed the operation. In this case, the Allow surface result option must be checked.

Modifications / Additional information:

This command can process bends with zero internal radii, but there must be one cylindrical bend face on the external side. It is also possible to unroll a cylindrical face by itself, or a succession of cylindrical faces.

Example of unbending a bend from a sheet with cylindrical faces (in blue).