Black Streaks With Set Smooth

I am trying to create a fire extinguisher.

When I use Set Smooth on the model and render black streaks appear that are not there when it is not Set Smooth.

I tried Control-n to recalculate the normals but that did not work.



fire.blend (152 KB)

The short answer: You need to use Auto-Smooth, add an EdgeSplit Modifier, or manually set which edges are sharp/smooth.

The long answer:

More of a techinal curiosity…
Why do only some of the edges have streaks if all of the faces are at the same angle?

The streaks are caused by an interaction between the smooth shading and the placement of your lamps. If you rotate the lamps around the fire-extinguisher, you’ll notice that the streaks follow them. Why does that come out as a streak? Not completely sure… I’d have to know the shading algorithm a lot more intimately than I do. :slight_smile:

You need to recalculate normals outside.

Ctrl+N in 2.49 in edit mode. But select all verts first.

if you read the first post, it says he already tried CTRL+N