enter image description here/Users/stephanepras/Desktop/Split Glass.png

I made a nice glass by spinning a profile 360° around Z axis with Spin Tool. Then when playing with Smooth modifier I see a split appearing along the seam!

This means both borders of the seam (i.e. the 0° and 360° vertices) never merged, despite I clicked AutoMerge Editing. Of course if I "Apply" after having used Smooth modifier, I get a glass with a slit…

How can I "weld" both sides of the seam after a 360° spin and avoid that ?

  • $\begingroup$ did you remove the doubles in edit mode? W-->remove doubles? $\endgroup$
    – gladys
    Aug 31, 2015 at 18:22
  • $\begingroup$ The error can still persist after remove doubles $\endgroup$ Aug 31, 2015 at 18:34
  • $\begingroup$ Yes, I did use Remove doubles. $\endgroup$
    – Stephane
    Aug 31, 2015 at 19:36

1 Answer 1


I would not use Spin Tool for this particular purpose, closed surface of revolution. Remove doubles, a necessary step, did not solve the problem. My problem was a hidden internal face problem. Hidden faces are bad.

My initial actions produced an internal face with Spin Tool. The face of the initial mesh. I had to remove edges and one internal face and then bridge edge loops to get the mesh in good form. The extra work seems unnecessary. Consider sleuthing down an internal unwanted face.

Perhaps the best evidence is that loop cut seems to have difficultly with the resulting mesh. What appears visually as a loop has failed with Loop Cut. It has simply created difficulties in your situation.

Finally I [deleted face only] before the spin tool and got the correct results. If felt if I were smacked in the face with a whipped cream pie.

I would use Spin Tool for corners of edited cylinders.

Consider Screw Modifier firstly. (Array Modifier if you feel adventurous)
I applied the Screw Modifier. Loop Cut worked as expected.

Followed by Smooth Modifier.

You might also just use proportional edit to achieve your [spin/lathe] shape.

  • $\begingroup$ Correct. Using Screw Modifier (with 0.000 screw path) produces the lathe shape with not gap, while Spin Tool was leaving one, revealed by the Smooth Modifier. I just wonder why I had to choose Y-axis for my profile to revolve around the Z-axis. Never mind, it works however ... $\endgroup$
    – Stephane
    Aug 31, 2015 at 20:06
  • $\begingroup$ Y-axis Why? Perhaps you should have NO rotation in your model. Apply rotation. I am giving a quick comment with no investigation. Or edit the vertices only in Edit Mode, thus no object rotation is applied. $\endgroup$ Aug 31, 2015 at 20:30
  • $\begingroup$ Since it is a lathe operation, I need an axis for my profile to revolve around (rotation). I'm just surprised to state the axis choice in modifier panel doesn't match with the world axis chosen in 3D view. By the way, after applying Smooth Modifier, I do not have any more split … but a hole all the way through, on the object axis ! Nobody is perfect. $\endgroup$
    – Stephane
    Aug 31, 2015 at 20:54
  • $\begingroup$ I agree you must specify an axis in the Spin Tool. To clarify .... some operations work best when the participants have the rotation and scale [applied]. Applied in the special Blender Sense from the menus. You will see Apply Rotation in the menus. Thus two objects may look as though they have the same orientation ... yet one has an object rotation active [non zero] and the other has the vertices moved and a rotation inactive [zero]. I do not have images of you object rotation ... I am just conjecturing. $\endgroup$ Aug 31, 2015 at 21:12

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