Not all components in an assembly showing up in Keyshot

[imfastrnu2]

I imported some parts into Keyshot 5 and they were there until I closed and reopened the file. They show up in the Scene Tree but do not appear in the 3D viewport. One of the attached images shows the area where the parts should be and I've circled in the scene tree that they are turned on. Does anyone know how to fix this?