Mirror surface failing


I need to mirror a surface to get it symmetric.
To do this, I have made the surface a little larger than it needs to be to have something to trim from.

My problem is that I can’t get Rhino to split, trim or anything else on this surface (made with patch, from outline curves).

I have also tried to matchsrf, without trimming the surface down the middle plane. This dosn’t work either.

What am I doing wrong?

How do I best mirror the surface?

Hello - I can’t see why mirror would not work if the edge is on the mirror place - is that it does not work or that it is not smooth across the mirror plane when it does? Can you post a file?


check that the cutting surface is larger than the patch. the split should work that way.

The split worked after I made the cutting plane larger than the whole patch :wink:

The mirror also works now, but I still cant choose any edges when the “Select untrimmed surface edge to change” request comes.

because the patch is trimmed to your input curves, and later, splitted. it doesn’t have any “untrimmed” edges. I would suggest using other methods than patch but I don’t know the context.