Click on the Click on the 
to display the Import 3D Dialog.
You can import any of the following 3-D file format types:
•STL This format was designed for 3-D printing and unfortunately only contains white objects as no material properties are defined in STL files. If possible you should use a different file format such as XGL. Find Out More...
•VRML Both VRML version 1 and version 2 are fully supported.Find Out More...
•XGL This is the recommended file format as it can contain material and colors.
Drop-down list of supported file formats
The Import 3D Dialog
Units and Scale
Both VRML and STL files do not contains units, so you may have to set the import scale. XGL files have units defined so you do not need to define units or scale.
Rotate
Different source define different direction for the vertical direction (distance from ground)
DEX designs the UP direction as the +Z However others use the +Y.
Check the 
checkbox to rotate the model 90° to switch between Z up and Y up.
Import Size
The import size is shown in the information box at the lower left. of the Import 3D Dialog.
3D Model Imported
When you import the model, the position or rotation may not be to your liking.
To rotate the model about an axis, select it and click on any of the 3 axis rotate button. 
To move the imported model, select it and hold down the left mouse button and drag on either the red, green or blue axis in the 3D viewport.
Drag the red, green or blue boxes to scale the model.
Drag on the red, green or blue circles to rotate the model.