Extract Midsurfaces

Use the Midsurfaces: Automatic tool to extract the midsurface of sheet metal stampings, molded plastic parts with ribs, and other parts that have thickness clearly smaller than width and length.

  1. From the 2D ribbon, click the Midsurfaces > Automatic tool.


    Figure 1.
  2. Optional: On the guide bar, click to define midsurface options.
  3. Select surfaces or thin solids.
  4. Extract midsurfaces.
    • Extract the midsurface from all selected solids/surfaces by clicking Midsurface on the guide bar.
    • Extract the midsurface from individual solids/surfaces by left-clicking on a selected solid/surface.
    Tip: When selecting surfaces, you can easily select opposite surfaces by right-clicking and selecting the Select Opposite option from the context menu.
The original geometry that you selected to extract the midsurface from remains unchanged, and the new geometry that represents the midsurface is placed in the component specified by the Destination component option.

Midsurface Method Options

The following methods are available when extracting the midsurfaces of thin solids.

Access this option by clicking on the guide bar.

Planes + Sweeps + Offsets
Identify the places where a piece of plane or a piece of a sweep surface can be used as a middle surface. A middle surface is constructed at the remaining places in the model, for example the places where planar or sweep surface pieces cannot be used as a middle surface, by the same algorithm as in offset via the offset of the model's sides.


Figure 2.
Planes + Offsets
Identify the places in the model where a piece of plane can be used as a middle surface. At the remaining places in the model, for example the places where planar pieces cannot be used as a middle surface, the same algorithm as in Offsets is used to construct the middle surface via the offset of the model's sides.


Figure 3.
Offsets
Create pieces of the middle surface by offsetting the model's side surfaces towards the middle. This is the traditional approach for midsurfacing.


Figure 4.
Skin Offset
Automatically detects the two largest faces on the model, detects the thickness, and then creates the middle surface by offseting one of the faces towards the other one by half of thickness. This is the quickest method for creating a midsurface. However, it is not applicable to many models.
Assumptions:
  • There are smooth transitions along the faces. Sometimes, certain non-smooth transitions may be handled by increasing the default geometry feature angle.
  • There are no smooth transitions at edges/holes from one face to another one, the transitions should be sharp enough.
  • No ribs are present. There should only be one face(plate) in the input.
  • No variations in thickness are taken into account.
The typical models where "skin offset" can be successfully applied are metal stamped parts.


Figure 5.