I am having difficulties with the Glass shader because there are no caustics and the shadows that show up in the glass shaded object look as if they are blobs of ink.
I do have the 'No Caustics' option disabled, and from the research I've done, this one checkbox is the only one that people seem to be mentioning when it comes to caustics.

Does anyone have advice on how to deal with this issue? Here's a screen capture of the scene setup that I'm working on.

enter image description here

  • $\begingroup$ I don't even have the "No Caustics" option. I'm also missing the "Sampling", "Light Paths" and "Volume Sampling" panes. What is going on here? $\endgroup$ – panzi Jan 21 '15 at 3:45

Lamps (with the exception of mesh lamps) will not cast caustics if they don't have Multiple Importance Sampling enabled on them.

Make sure any lamps in your scene have this enabled:

enter image description here

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  • $\begingroup$ That works, I'll post the problem of exaggerated internal shadows some other time if no one shows up with ideas on that. Thanks for the caustics clarification. $\endgroup$ – MarcClintDion May 21 '14 at 3:43
  • $\begingroup$ I found a way to clear up the inky black shadow problem. With several lights, if one of them has shadows disabled then it will brighten up the dark areas inside the mesh. $\endgroup$ – MarcClintDion May 21 '14 at 5:48
  • $\begingroup$ Glad you got it worked out :) However, in the future, separate problems should be asked as separate questions. $\endgroup$ – gandalf3 May 21 '14 at 20:13
  • $\begingroup$ I don't have such an option here. :( $\endgroup$ – panzi Jan 21 '15 at 3:48
  • $\begingroup$ @panzi What version of blender are you using? $\endgroup$ – gandalf3 Jan 21 '15 at 5:04

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