Final answer:
To rotate a part file in a SolidWorks assembly, select the part, use the 'Rotate Component' tool or the 'Move Component' tool to specify the angle and axis, and then save the assembly file after the rotation.
Step-by-step explanation:
To rotate a part file in an assembly SolidWorks, follow these steps:
Open your assembly file where the part is located.
Click on the part you want to rotate to select it.
Once selected, use the 'Rotate Component' tool found under the 'Assembly' toolbar or simply click and hold the right mouse button and drag to rotate the part freely.
If you need to specify the angle of rotation, you can also use the 'Move Component' tool, input the degree of rotation, and select the axis around which you want the part to rotate.
Complete the rotation with a click to confirm when the part is at the desired orientation.
Remember to save your assembly file after making the changes. This will ensure that the rotated position of the part is updated and saved within the assembly.