Import and Export

The fourth group of preferences are geometry exchange (import and export) options.

Import
Automatic Collapse After Import: If this option is set then after reading one external format file (IGES, DXF, etc.) one global collapse is made. If it is not set, all surfaces and lines will be independent of each other.
Automatic Import tolerance: When importing a file or collapsing entities, any points closer together than this distance are considered to be the same (see IGES). Lines and surfaces can also be collapsed.
Collapse:
·Ignoring Layers: Entities are also collapsed if they belong to different layers.
·Each layer separately: Entities in different layers are not collapsed. (Entities belonging to frozen layers are never considered.)
IGES: Curve on surface from 3D: If this option is set, IGES curves on surface entities are created from the direct 3D space definition (recommended); if the option is not set, IGES curves are created from the surface space parameter definition.
IGES: Create all in 'layer to use': If this option is set the IGES entities are created in the current layer to use, instead of using the file layers.

Export
IGES: B-Rep output style: If this option is set, exported IGES volumes are written with Boundary Representation Solid Model style; otherwise its surfaces are written as separated trimmed surfaces without topological information.
Some CADs are not able to read the IGES B-Rep style and then can be interesting to use the alternative style.