Grasshopper - vRay render - geometry visibility problem

Hello guys.

When I change the geometry linked to the node, I cannot see anything from render viewport. From the video you can see when I change from a piano to a cube, I cannot see it. The material is the same, everything is the same.

Do you know why?

Thank you in advance.

Benvenuto Daniele!

Di componenti GH VRay non so nulla mi spiace. Chiedo: lo stesso modello con gli stessi settaggi “fissi” (fuori GH") funziona come atteso?