Render the covered object

Hello, everyone.
I have two objects to render, one is covered by the other, how to draw the covered object in VTK?
In OpenGL, I can set the GL_DEPTH_TEST, but I can’t find the api in VTK, thanks.

The red line is back of the green line, but we can see the red line

Who knows?

Maybe set 50% opacity as a property of the actor or the mapper?