Including multiple objects –

While using the Rectangular Pattern command in the Part Design module, you can include multiple objects in your pattern. To do so, just multi-select (while holding the CTRL key) the objects before clicking on the Rectangular Pattern command. You will then see the list of objects to pattern in the "Object to Pattern" section of the dialog box.

Improve .stl File Accuracy –

To improve .stl file accuracy and to reduce faceting on .stl files, go to tools/options/display/performances. Change 3D accuracy from fixed to proportional, and change the setting to .02. Make sure the curves accuracy is set at 100 percent

Including multiple objects –

While using the Rectangular Pattern command in the Part Design module, you can include multiple objects in your pattern. To do so, just multi-select (while holding the CTRL key) the objects before clicking on the Rectangular Pattern command. You will then see the list of objects to pattern in the "Object to Pattern" section of the dialog box.