Screw modifier destroying my normals

Hello everyone !

I’m currently modelling a small (somewhat humanoid) strawberry for a game I’m making. I decided it would be kind of “zombified” (it being an enemy and all) and would have thorns representing kind of its state. I’m working pretty low poly for both time constraints and performance reasons. Now These thorns are on a vine and I decided to have it kind of a “vine entangling” effect (basic but it can give more interesting results in my opinion).

Now my basic shap is as follow :

then I decided to apply a screw modifier on it, the only problem is the result gives weird face normals (some being flipped) and most of all, the vertices normals are all over the place and make no sense at all. Recalculating it manually after applying fixes it, but not before. The problem is I’m planing to use a bezier to wrap the vine around the strawberry, so I’d like to keep non-destructive modifiers as much as possible. I’ve seen people do that for spiraling items many times, and never face normals were an issue. Here is an image of the final result :

My question is why is that doing that, and how can I avoid it ? Am I doing anything wrong ?

Thanks in advance everyone :slight_smile:

Small edit : I tried all combinations of options in the Screw modifier, none worked :frowning:

Edit 2 : Doing more tests, it seems converting the shape in a triangle fan fixes the problem, but because of how spin works (and it makes sense it shouldn’t work any other way) it creates faces inside, and full faces at every step of the spin.

I created a hollow shape like yours and had no luck recreating the issue. I tried many iterations, but couldn’t break it. Is there duplicated geometry somewhere? Try making the shape the original way and then merging points.

One thought that crossed my mind as being able to break the geometry is I created “control” edges between the symmetrical points of each of the 3 “branches” (so as to be able to scale along normal and scale individually while keeping everything the same) then removed them ! That may have screwed with the normals. Taking your advice into account I guess I’ll just recreate it from a point extruding it and snapping to vertices ! Should I however file a bug with what I assume to be the steps to recreate it ?

In all cases thanks a lot :slight_smile:

Edit : Boom, a small recreation from scratch, a Triangulate and an EdgeSplit later, here we go :


Thanks a lot. Thanks to that I also ended up noticing something very weird. When recreating it, I tested two methods for creating the last edge. The one I ended up using, that worked, was extruding then auto-merging to last (manually merging likely would have resulted in the same outcome). However, when selecting the two last vertices and creating the edge with F, I ended up having the same problem along the loop of face that were extruded from that edge (that particular loop was flipped), so the manual creation of edges between the vertices is definitely the issue here, but I still wonder if it’s a bug or just a misuse.

Maybe I’m not sure what you are doing. This is what I get.


is there something I am missing.

No as I said recreating from scratch I ended up with your result :wink:

It’s just when messing with creating edges using the F button that the result ends up being weird (but not all edges or creating internal edges then removing them)

Alright then. Been working all night, so sometimes I get a little slow.

Ahah don’t worry ! Go rest a little then :wink: Good day to you and thanks very much again !