Control point symmetry

Hello, I just wondered is there a way to make a single surface totally symmetrical whose mirror plane is defined by a line or a plane surface, so that when I select a bunch of control points on one side of the surface, the control points on the other side of the mirror plane will take the same (but mirrored) values for their position? I’m aware of the “Symmetry” tool, but it only works on a half model that’s mirrored along the mirror plane, making it impossible to have a single surface with symmetrical control points (unless “Merge surface” is used, which complicates or alters the original shape tiny bit).

In the example below, I selected the control points in the right side and the goal here is to have the corresponding control points on the lefts side following the same position, but mirrored along the mirror plane that is defined by the while line. Note that if only the selected control points must affect their corresponding control points on the opposite side, i.e. not the whole opposite side of the surface.

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I can see no easy way to do it… Yet I could help with this particular surface if you like

This is just a random surface I made as an example in order to better visualize my idea. The slow way to do it by making a mirror copy of the control points and snap the opposite end control points to the former. But it takes ages to do so with surfaces that have plenty of control points.

True… I almost sure that Grasshopper solves such a giggles as one plus one… Not into that thing unfortunately : ( But the VSR symmetry tool do it in one click.

I only have Rhino 6 evaluation for now. I’m curious if there is a way to do this symmetry of control points natively in Rhino, with no paid plugins…

Unfortunately AD killed it years ago along with the T-Splines and nothing similar we have so far. I advice to ask in Grasshopper section, all the way someone have had that task solved. Good luck!

Yeah, Autodesk are interested in making their own CAD programs more feature-packed to boost their sales. It’s something to be expected, though.

Hi Bobi - V7/WIP Subd has Reflect but there is nothing for surfaces.

-Pascal

VSR does this, only if the surface is split and mirrored along the symmetry axis though.

Wrong : ) Try ADSymmetry instead of ADAlignSymmetryPlane

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Man, I tell you, I use AD shapemodeling for a couple of years now practically on a daily basis and I somehow managed to completely ignore the ADSymmetry command.
Doh, never bothered to right-click that icon…
Thanks so much I learned something new today.
And something very useful too! :+1:

Prefer to call is VSR : ) Thing’s full of many hidden secrets. Pure gem, yet forbidden… :expressionless:

Still no “Control point symmetry” tool to this date? :space_invader: Is it ever considered for the future? This is a hugely needed tool since the majority of surfaces built by Rhino lack symmetry, despite using totally symmetrical input curves.

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Hi Bob,
+1 for this function to be implemented.
Maybe this subject could have more attention if it was posted in the"VSR end of life" thread.

By the way, I found a demo in youtube (from Joaquín Laborda) explaining this function:

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Hi Jordi, the control point symmetry showed in the video you attached is exactly what my request is for. It’s an incredibly usable tool for VSR users and it’s pity that even the Rhino 8 WIP still lacks such functionality…

Yes, very necessary for a high-end products this functionality.
In addition to that I wish it would have history(like symmetry in Rhino) so you can tune one side up, and then it updates automatically the whole patch keeping the symmetry.

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Can you set up curves to loft ahead of time? There’s no way to retroactively set this up, but it’s fairly easy to reverse engineer from a starting srf. I use symmetric surface editing all day, every day.

RadialSymmEditing

AxialSymmEditing

If you’re interested, we can jump in a voice chat and I’ll show you. There are a few caveats:

  • You’re stuck with whatever degree you initially select in CurveThroughPoly, but you change the number of spans afterward.
  • The seam/dir can randomly flip on you, but you can do something silly to flip it back.
  • The V will match the degree of the curves you Loft, but the U will always be deg3 until this gets added.

Thanks for the suggestion. My request is about a symmetry tool that affects the control points of existing surfaces. Often times Rhino will produce non-symmetrical output surfaces (Sweep 2 rails, Blend surface, Network surface, Loft etc) despite using totally symmetrical input curves or surface edges. This is where a proper “Control point symmetry” tool can help a lot by fixing the imperfections that Rhino produces with certain tools.
Being able to move a symmetry (mirror) plane, as showed in the video posted by Jordi Rovira, is also a nice touch that offers unlimited possibilities to people who want to get creative.

Don’t get me wrong, I fully support your feature request. Everything I work on has 1, 2, or 4 axes of symmetry or radial or radial + axial…that functionality would be very welcome to my workflow.

I consider everything I do as little hacks to get me by until those full-featured VSR tools are built. Like I could reverse engineer the surface you showed and set up a new surface with symmetry on a mobile mirror plane in about a minute, but that’s a minute longer than using a purpose-built function, and I’m still burdened with a list of caveats.

AxialSymmEditingMovePlane

Since McNeel employees often are fond of technical reasons, what is the technical reason that Reflect can’t work for control points on regular surfaces? Is it that the work simply stopped when the bullet point for SubD was fullfilled? Nobody took an extra day to make sure it would work on a surface as well?

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