Subsurface modifier, corner acting strange

Hello there,

Been a while i have been blendering. I started some time ago with blender but stuff got in between that and in the meanwhile my drive with blender + all saves stored on it died … so … I started again with blender , from scratch because i forgot most of all i learned. Now i am remaking my logo again and i stumbled upon a problem. Most stuff i tend to find in videos on the net and here on the forum etc. But not this problem. Maybe im not formulating it right , idk. But this is what im facing:

I have my logo, think my topology is kinda … ok? And i applied the subsurface modifier. This works great on most parts. But on some objects , some corners do strange things. Although the opposite corner has the same/mirrored topology and is correct.

Anyone got an idea why this is happening:

This is the model with the topology showed. It has all quads and i shape the corners sharp with extra support loops, wich mean that every sharp corner has 3 edges. Probably not the best method, edge crease maybe is but havent looked into that yet since the thing i was doing was working great till now.

here u can see on the left, the normal corner and on the right it goes pointing outward? why is this?

thanks in advance.

The shown topology shouldn’t result in that creasing. It’s likely a doubled face or discontinuity.
If you provide the mesh, somebody can likely demonstrate the issue.

1 Like

Ok here is the part with de pointy corner some other parts have same issue

pointy.blend (590.1 KB)

You had an extraneous coplanar vert in there. You can fix it in three seconds by merging by distance.

You have overlapping vertices.

Select the whole mesh in edit mode and remove doubles if using 2.79 or merge by distance if using 2.8+

As mentioned by the other posters, you’ve doubled faces. I would assume you were extruding and then cancelled the extrusions transform step, but not the extrusion operation.

It’s easy to check for issues like this with the mesh analysis tools

How do i detect overlapping vertices? i guesse with the mesh analysis Ben_Morrison mentioned? I can select all and then merge by distance, but then the model is very curvy again. But i guesse i can restart creating edgeloops again and see if it fixed it.

I can follow u here but i think , that u maybe think this because i added a extra loop on the underside corner to create a sharp corner with the modifier and i set the loop ontop of the lower corner edgeloop. I guesse i should use a other method for this?


A “Merge By Distance” will always remove overlapping vertices, within the tolerance distance.

Issues with SubD almost always boil down to overlapping/redundant verts, coplanar polys, and unwanted internal (usually) polys. They can be devilish hard to track down though.

I make sharp corners on the SubD like this:

Cleaned up object: selected all , merged vertices by distance, 128 merged… ok.

then i add loopcuts like the red one and move them very close , as close i can. Ontop of the blue one( not on this picture , its just to show u )

i then mostly get this result:

I checked the mesh analysis. but i dont really understand whats going on there, i see red faces… but what they mean i dont know. , i redone this object and its not showing red faces so guesse thats good.