I'm having a bit of an issue trying to simulate water in a glass bottle. For some reason there seems to be some refraction that causes the water to bend upwards and creates a weird effect(a sort of upwards bump).

Can anyone please shed some light on this situation and explain why this is happening?

I have also attached the blend file below:



enter image description here

  • 1
    $\begingroup$ That all looks physically accurate. Realize that the bottle acts as a lense, so it distorts things behind it $\endgroup$
    – J Sargent
    Commented Dec 5, 2015 at 17:34
  • $\begingroup$ While I understand that some distortion should occur, I have seen other results on the internet that don't have that weird bump. Scaling the water object doesn't work. $\endgroup$
    – Enit
    Commented Dec 5, 2015 at 17:39
  • $\begingroup$ Ah, I think that is a reflection on the bottle $\endgroup$
    – J Sargent
    Commented Dec 5, 2015 at 17:39
  • 1
    $\begingroup$ related? blender.stackexchange.com/questions/2823/… $\endgroup$
    – user1853
    Commented Dec 5, 2015 at 18:37
  • 1
    $\begingroup$ If you don't like them, perhaps adding a backdrop will get something closer to what you want. Here's an example render $\endgroup$
    – gandalf3
    Commented Dec 6, 2015 at 7:26

1 Answer 1


What seems to be happening is the light is hitting the bottom of the glass, going through it, and then reflecting upwards hitting the top of the bottle, creating a weird reflection. The reflection changes based on the angle you look at the object.

I'm pretty sure that this is working how it's supposed to. It just looks weird to the eye. There are a few things you could check/do to fix it though.

  • Check to see if the liquid, is touching the glass. This is known to cause artifacts.
  • You could change the camera position or lighting to make it less apparent.
  • You could also adjust light bounces in the light paths drop down in the render panel. (this would decrease the realism, but you could lower the bounces so that the light doesn't reflect enough times to cause that reflection)

I think you might benefit from this tutorial. I linked it at the point where he started doing the liquid.


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