Screw modifier creates topology through object

Hey there,

I am trying to model an anatomical accurate eyeball using imported svg shapes from illustrator and apply a screw modifier to generate a radial symmetric object. The problem is now that, even though the shape’s edge aligns with the Y-axis, the modifier generates faces through the center of the object. This leads to a hole in the object when applying e.g. a subdivision modifier to the object (after applying the screw modifier).
When I delete the center line of my svg shape the hole is gone, but all render engines produce strange artifacts.
My main goal is to avoid this from happening and generate a clean object topology.
It would be great if someone could give me some tips here. Thank you! :slight_smile:
I also attached the .svg file, it does not have a line-width; in blender i convert it to a mesh and unify faces using “F”. (Blender Version 2.93)

This is the SVG file i use
SVG_Cornea

The image isn’t showing any helpfull information. Wireframe for a partial shown eyeball ??? . You should show your initial mesh and then the result (and maybe not you inital import SVG, which isn’t shown…). If the mesh does have edges across local 0,0,0 then the screw modifier will rotate them over it and the geomtry will be weird anyway.

Hi Okidoki,

You are right, the svg is not “shown” but one can drag and drop the file after clicking in the free space below the text. (it is the cornea of the eyeball)
So you suggest not having an edge at 0,0,0, right? As described above it leads to strange render artifacts and subdivision problems.
Here is a quick overview of the steps:


Let me know if you need more info. :slight_smile:

A thought: in Screw Modifier > Normals try checking Calculate Order and see if the artifact is still there.

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Ah yes the file is shown/has a preview which is …? transparent or whatever…

Select merge in the screw modifier.