Interface > Working with Imported Geometry > Basic Methods > To Generate a Solid Using Surface Data
  
To Generate a Solid Using Surface Data
When all surfaces in the imported data are not joined automatically,
1. Select the feature in the Model Tree.
2. Right-click. A shortcut menu appears.
3. Click Edit Definition on the shortcut menu. The Import tab opens.
4. Click to rejoin the quilts.
5. After defining a single closed volume, click to create the solid feature.