I am seeing a slightly unusual problem with importing from Illustrate into TWX Studio. In Illustrate, if I import additional assemblies into a project and then save that project as a .c3di and then publish as per normal in .pvz, while this saved .pvz displays perfectly in Creo View Express (as in it shows the additional assemblies), when I import the same .pvz into Studio, all I get is the original project without the additional assemblies.
The Studio Preview is the same as is the viewed project in HoloLens; all missing the additional assemblies applied in Illustrate.
One possible thing could be that the component is there but is not visible. If I have some problem I will create a new 3d Model Item for a particular visible occurrence - let says "/46/12" and will check in Creo View where the display is OK the value of the Creo View Attribute Part ID Path (actually in Creo Parametric the ProComponentpath if it is coming from Creo parametric ) and will try to change the value of the component which is not displayed (let say /46/22/3 and see if I there is an error in Strg-Alt-I (debugger mode) or if I could set the visible property to true of this Model Item.