A black streak upon rendering in cycles.

Noticed a black streak upon rendering in Cycles. How do I resolve this issue and what caused it?

I am a complete beginner to blender.

  • $\begingroup$ Hello could you please show a screenshot? $\endgroup$
    – moonboots
    Sep 19 at 11:46
  • $\begingroup$ I'm sorry, but I see no black streak... $\endgroup$ Sep 19 at 11:59
  • $\begingroup$ i.postimg.cc/0yTbKqxx/belnder2.png it can be observed in one of the icing drippings. @GordonBrinkmann $\endgroup$ Sep 19 at 12:30
  • $\begingroup$ the big "O" shaped black area is a shadow. The small vertical black line is also a shadow - caused by a crease in the topping. $\endgroup$ Sep 19 at 12:30
  • $\begingroup$ i.postimg.cc/0yTbKqxx/belnder2.png the black streak can be observed on the icing drip @moonboots $\endgroup$ Sep 19 at 12:31

1 Answer 1


You have some weird inner topology there causing the black streak. Select the donut dripping mesh, go to edit mode and choose Select > Select All by Trait > Interior Faces. With enabled X-Ray mode you should see something like this:

enter image description here

Hit the Del key and select Faces to delete all this inner stuff and the black streak should be gone.


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