Mirror modifier without seam I'm using mirror modifier with merge and clipping enabled to create a very low poly model. Generally - every single triangle counts. I'm also a newbie, so this question might be stuipid.

Is there a way to use mirror modifier so that it DOESN'T create new vertexes at the point my model and mirrored parts merge? I know they are needed in most cases, but in my it's just extra work to remove them.
Assuming you mean by seam an edge loop like the one selected in this image (along the y-axis).



Once you have applied the mirror modifier you could:


Select the edge loop Ctrl-RMB
Delete edge loop X


I wouldn't recommend to apply the modifier since you couldn't apply symetrical changes as easy as before. IMHO it's not worth to sacrifice editability for saving a few faces.