How to make the segmented trachea transparent

Hello all. I am a radiologist and have found 3DSlicer to be incredibly useful.

For my research I have the chest CT data where there is a foreign body with soft tissue intensity in the trachea. I hope to present the foreign body with the trachea in 3D. I used segment editor tool and add two VOIs, one for the foreign body and another for the trachea, I click “show 3D”. but find the foreign body is not visible due to the shelter of the trachea.
how can I make the trachea transparent to better show the foreign body in the trachea in 3D?

Thank you very much.

You can control the opacity of individual segments through the Segmentations module.

@linyao You may also want to experiment with the ColorizeVolume module in the Sandbox extension. It allows you to use your segmentations to control the volume rendering of the CT data in various ways.