mirror and subsurf modifier problem

Hi all

I expect there is a simple answer to this but I can’t seem to figure it out.

When using the mirror and subsurf modifiers the mesh seems to break as I have circled in the image

How can I stop this from happening ???

I have merge and clipping options enabled in the mirror modifier but as soon as I use the subsurf modifier it ’ breaks ’ the mesh if I use Catmalk-Clarke. If I use simple subsurf it is fine



Move the mirror modifier above the subsurface in the stack, by clicking the little arrow (up facing triangle) in the upper right corner of the modifier.

Stack order is important.

Thanks for the quick reply Photox

I have done as you have said and moved the mirror modifier above the subsurf, but the mesh still breaks.

Figured it out

It was the merge limit on the mirror modifier, it was set too low, adjusted it and bingo, all fixed

Thanks anyway Photox.

You still should always have the mirror at the top. If you keep subsurface at the top and just increase the merge limit you will run into problems with verts close to the center merging when you don’t want them to. Move the mirror on top, turn off subsurface and fuse the verts by moving them and then turn subsurface back on.

Increasing the merge limit is not the solution, it is just a temporary fix which creates new problems.

Thanks Photox I will remember that next time.

Is there any info on how best the modifiers should be stacked ???

If the merge limit is not adequate, it means that the vertices aren’t exactly on top of each other, and object might have unapplied scale. It’s possible to still have artifacts either with subdivision or shading if there are interior faces, mesh is using creasing, sharp edges, or custom normals.

Which one? Upload an example .blend when asking questions and the first one to answer is likely tell you how to fix it, with images. Tutorial linked in my signature shows how to prepare and upload.

After awhile you just develop a sense of how stack order affects things. You can temporarily disabled a modifier in the viewport by clicking the eyeball icon, and you can disable it in the render by clicking the camera. The stack is applied starting at the top first. Experiment and move things around and you get it. But mirror on top and subsurface below is extremely common. See when you have the subsurface at the top the vertices near the center are pulled away and some move beyond the merge limit.

A modifier will affect the modifier above it. So if the SubD Surface modifier is at the top, it will will deform the mesh and the mirror modifier below it will mirror the deformed mesh. If the mirror modifier is placed on top, it will mirror the mesh and then the SubD Surface modifier below it will deform the whole mesh.

thanks for all the help guys, very quick answers