Concentric glass tubes

[jhiker]

This may have come up before but I can't find the answer.
I have two concentric glass tubes in my model. Presently the material is set to 'Glass basic' and 'two sided'.
When I have two tubes showing the inner one is opaque. If I hide the outer one the inner one looks OK.
How can I have them both look like glass?
Thanks.

[jhiker]

Ah - I think I got it - simply increase the ray bounces - that right?

[guest84672]

Yes and turn on global illumination in the settings tab.