Any tips to make object transparent at the the center?

I want to make a tube that looks like this

from every angle but I’m having trouble. When i rotate the camera it doesn’t look as good.
This is my not setup

i was thinking volumetrics would be better but couldn’t get anywhere close with that either.
Any advice is appreciated!

Hi, I deleted my first answer because I did not read “from every angle but I’m having trouble. When I rotate the camera it doesn’t look as good.”

This is an interesting question, the problem is that the light has different incidental angles as you turn the camera and changes the reflections on the tubes surface. I have done various experiments with little luck the closest I got was this:

For this I lowered the fresnel IOR far enough so that only the silhouette was shown from all angles.
This unfortunately gets rid of the nice plastic-like roughness.
So I tried to add some by mixing the bottom nodes (very slightly.)

The other problem that occurred was that from the back angle the tube disappears (dark side of the moon!), so I added another light opposite to the first one that gives a rim light on the back side. In the screen shot both lights are lighting the tube.

I know it is probably not exactly what you want but I thought I would post it in case you were curious about why I deleted my first post!


This gets me way closer than what i had, I’ll keep playin with it. Thanks for taking the time!!

Use fresnel when you want accurate mix of absorption and glossy contributions, or when total internal reflections are important. Use layer weight/facing for anything else as you get a nice 0-1 range that is easier to manage. Fed through power 5 + 0.05 will give you a curve close enough to fake glass fresnel.

That said, I don’t think what your asking for can be done in 3D, not with the tools we have available. You could try to render it out as line art, blur the line, and use the image with window coordinates. I can see line art as a available buffered prepass be useful in materials for many purposes.

I’ve had fun experimenting with this. I took a different approach to counteract the light at grazing angles. I created a gradient based from the angle between the camera and normal, then adjust the fresnel with it. This removes some of the reflections at grazing angles so that you still can see through the object.

green_tube_blend-02.blend (872.4 KB)

Here is another example with different shader settings

green_tube_blend-03.blend (872.4 KB)

Thanks for taking time to try it out. Its close to what I’m after. I’ll keep playing with settings tomorrow! Thanks!