Low Poly mesh has seam down the middle

[Grizz]

Hey I am doing the retopo for the orc and I noticed a strange shading seam going down the middle. I was hoping it was a viewport bug so I kept going and I am now on the decimate horn stage. Since it did not go away (surprise) I investigated and found that the normals of the vertex are at an odd angle in the middle so that causes the shadeing issue see pic

Is there any way to fix this? recalculate normals, apply mirror, etc does not seem to work
This is how it looks from afar.

The face normals are in the right direction.

[NP5]

Why is merge in the mirror modifier animated?
Good close ups showing the odd angle normals and well discovered.

Do you have an internal face Along the centre line?

General Q&A note
Help us all to help you.
Please give full screenshots with any questions. With the relevant panels open.
Also, include the lecture time and name/number that is relevant to the problem/issue.
This can be done by Blender itself, via the ‘Window’ menu bar top left hand side.
On that menu drop down is ‘save screenshot’.
Close ups additionally where they help.

[Todd_Vance]

Mirroring sometimes causes that. After applying the mirror, you might try the smooth brush all around the seam. I’ve fixed it before and am trying to remember what I did. If it wasn’t the smooth brush, I might have turned “dyntopo” on and set the amount to something a little smaller than the current resolution, and then used the “simplify” brush to just change all the faces along the seam. That fixes a lot of things, though sometimes you have to use the smooth brush afterward to fix the glitches “simplify” leaves in its wake.

Oh, and as NP5 pointed out, sometimes I discovered an internal face doing it. Sometimes the Select menu, select all by trait, “internal faces” will find them, but sometimes you just have to zoom and wiggle the point of view till you are inside the model and look for internal faces.

[Grizz]

ah thanks that was it! for some reason auto mirror created a face when it cut the orc, or something else caused it. Deleting the inner face solved the problem, I looked so odd that I didn’t even see it when I turned the mirror off.

[Grizz]

Thanks Todd, as NP5 mentioned it turned out the orc had a face on the x axis where auto mirror cut it. Not sure how that happened but deleting the face solved the issue. Glad I didn’t have to go back to sculpting for the low poly model