Check/fix surface symmetry script?

(Gustavo Fontana) #1

Hi all,

Sometimes I’ working on surfaces that are symmetrical and the I need to do rebuild, or manual point editing with MoveUVN. Is there a way to check and also fix symmetry of a surface control points across a mirror plane? Right now I have to do this manually by using ExtractPt, split the points in two groups (one for each half). Mirror one group to the other side and look to see if SelDup gives me result or a duplicated group. This is of course just for checking. For fixing I have to manually move points in one half of the surface to the extracted points group form the other half. Like this:

In most cases I model only half of something across a symmetry plane, but sometimes I need the whole thing with no seams. Is there a better way? anyone has a script for this?



(Pascal Golay) #2

Hi Gustavo - I have a tool that does something like this, I’ll dig it up and see if it might help.

@gustojunk - the thing that I have is um, not very evolved… looks quick and dirty but I think it works - if so, we can work on making it a little less clunky - like remembering the symmetry plane…
Current workflow is, select some points on a surface, and set a symmetry axis - if there are corresponding points on the other side, it should work…

Hmmm - it was made for and tested in ‘proper’ four-sided open surfaces, I am not at all confident it will work on closed or periodic surfaces as in your image… If the computer starts to smoke, well… ask it what it’s smoking.

RunPythonScript or
! _-RunPythonScript “full path to py file inside double-quotes” (1.9 KB)


(Gustavo Fontana) #3

Thanks Pascal,

like this?

no workie :unamused:


Try forward slashes instead of backslashes in your path? Oh, and make sure they’re straight quotes and not curly quotes…

(Gustavo Fontana) #5

That is not helping either (which is a good thing, that would have been a tragedy)


Still looks like you have curly quotes…


(Gustavo Fontana) #7

OMG Mitch! that was it. Thanks for the tip.

Hi Pascal, I tried, not luck:

Also the issue is that blendSrf is not making symmetrical surfaces from symmetrical input, unless I did something wrong?. See left and right side have different point count:

Is this possible? also if I have a symmetrical surface, after I rebuild it does stay symmetrical, correct? (because it should)



(Pascal Golay) #8

Hi Gustavo - yeah, that is a closed surface in one direction, I doubt the tool handles it - I’m sure it’s possible, it just did not come up for the user asking for this, I think they are just making rectangular things - windscreens or something. I’ll have another poke at it.



Edit - trim/split in half - mirror - join?

Perhaps too simplistic for your purposes, but I do it all the time when applicable.

(Joaquin Laborda) #10

I assume you all remember how VSR handles this issue, something like this would be ideal.


Indeed! In fact, for v7, focus on any new (to core Rhino) modeling tools is ideal at this point in history, IMO

Me too! Sorry G, had I been reading more carefully and thoroughly, I would have noticed your ending statement, and avoided my peanut gallery advice, which was already obvious.

Jet-lag stupor…