How to get rid of internal shadows/blackness in glass/transparent/refractive materials? So I'm trying to make some very refractive glass in Blender Cycles. I've tried using the mix shader with Glass, Trasparency, by a factor of Is Shadow Ray + Is Reflection/Trasparency Ray etc, and I've also messed with every setting in the Light Paths section of the Render Properties.. but nothing will get rid of these black corners (see picture below), even though there is nothing black or unlit in my scene. 

In the past I've used Cinema 4D, and I would just turn off every channel in a new material except for Trasparency, and then just mess with the Refraction value, and I would get a very clean, realistic-looking glass material (see picture below). You can still see a few black spots I think, but, it just looks so much more refractive and clean. What I'm wondering, is what Cinema 4D does by default in this scenario, that Blender doesn't, and what settings I need to adjust in Blender to get the same result as Cinema 4D's default Transparency/Refraction settings. Any help would be so much appreciated!! Thank you!! (I've searched through YouTube, and Google Search, and this website a ton looking for every related keyword I could think of, but haven't found the answer to this issue yet :o the closest thing I found was this What&#39;s the difference between refraction and glass shader? and at the end of the answer the guy even says he doesn't know what causes the black bits)
I see you have Transmission bounces set really high, but I think one of the causes might be a lack of Glossy bounces which is actually what handles all the reflections on the Glass shader. Without it, Glass would just refract and be transparent.