Adjust the size of the model. A value of 100% corresponds to its original size.
Some FBX files are loaded with a scale multiplier different than 100%. This is because the file contains information that it should be scaled up or down.
Select the measurement unit used in the modeling application that the model is coming from. In this way, the exact model's scale will be preserved in SketchUp.
SketchUp uses inches internally (this cannot be changed). So if you choose "cm", for instance, the conversion will be from inches to cm, hence the model will be scaled down by a factor of 0.3937 (1/2.54).
Select an axis to be used as the up direction of the model, so that it is correctly oriented in SketchUp.
This is particularly useful if the modeling application that the model is coming from uses a different coordinate system.
This moves the origin of the model (its pivot point). This is especially useful when the geometry has been modeled far from the scene's origin.
Bottom Center is very useful when converting plants or pieces of furniture.
This softens edges between coplanar faces, just like in SketchUp. This setting is enabled by default.
When set to a value higher than 0, edges connecting faces with an angle higher than this will be smoothed. This is identical to the same function in SketchUp.
Known issue: the preview currently displays all the model's edges, even smoothed one. However, they will be correctly exported to the SketchUp file.