Surfacing techniques are useful in making modifications to parts, especially if the part is imported and has no feature tree. One such modification is removing holes of an imported part. The following examples assume that the imported part is a solid body with a hole through it.
The most common method is to use the "Delete Face" feature on the inside face of the hole, patch it up with a feature like a "Filled Surface", and then merge the faces together.
However, there is an easier method of doing so. Note that this method will only work on surface bodies. After deleting the inside face of the hole, the part should become a surface body. This can be confirmed by seeing the blue edge on the hole which indicates an open surface.
Then, simply select the edge of the hole and hit the "Delete" key on the keyboard. Normally, the delete dialogue box to delete the feature will appear but instead, you will see the following dialogue box:
Selecting "Delete Hole(s)" will automatically fill up the hole and knit that surface. This will appear in the feature tree as a "DeleteHole" feature.
This feature will work for any hole in the surface body, ranging from circular holes to irregular holes as shown below.