How to mirror a manipulation?

[Anonymous]

When working with parts that are suppose to be symmetrical, is there a way to manipulate polygons so that the actions are replicated respective to the plane of symmetry?

I've attached an example that i'm working on. In reference to the video, what i'm trying to do is to rotate both faces equally towards each other.

[10DSpace · Accepted solution]

@Anonymous 

The only way I know how to do that is to delete half the couch and use the symmetry modifier on the couch model. Then when you rotate the polygon on 1 side the poly on other side will be symmetrically mirrored across the symmetry plane.   This is the basic use case for the Symmetry modifier and it looks like your model is symmetrical so it should work for you.  Hope it helps.

[Anonymous · Accepted solution]

Hi 10DSpace,

Thanks for your reply.

I took a similar approach, by deleting half and just mirroring the other and joining it. This seemed to work, though after adding a turbosmooth modifier the surface 'kicked up' (see images). Looking at the editable poly, I can't see why this is? (I will note that the back edge against the mirror plane doesn't create a loop, or at least it doesn't select one when I attempt to. Not sure if there's a hint in that somewhere?).

I will of course try your suggestion too, and see what happens.

[10DSpace · Accepted solution]

@Anonymous 

The kink is because the vertices along the edge in the middle are not welded. When you mirrored the object there were 2 edges in the middle where you want the halfs to join and therefore the vertices along these edges need to be welded for turbosmooth (and edge loop) to work properly. To fix this, go back to the Editable poly level and select all of the vertices along the center line.  Then weld them with a low threshold value.  You may have to tweak the weld threshold value a little depending on how close the double vertices are to each other and the overall size of your object.    

[Anonymous]

Thanks for the support.

Should I somehow join the two sides together first, and then weld? I ask because I can't select the vertices of both objects at the same time, now that I have two separate poly parts.

[10DSpace · Accepted solution]

@Anonymous 

Yes, you have to attach them first by selecting 1 of the objects and in the editable poly rollout, selecting attach and then click on the other object.  (Note: Remember to de-select attach when done to avoid accidentally continuing to attach objects in the scene).  

Some of the advantages of using the symmetry modifier are that (1) you get real-time display of changes you are making on both sides of the mesh and (2) you are already working on a single object.   Same as for the Mirror function, you do have to watch where the symmetry (mirror) plane is on some meshes (it is movable via the gizmo in the symmetry modifier) and there is a built-in weld threshold which you can also adjust in realtime.   The Symmetry modifier is worth mastering as it saves a lot of time in modeling.    

[Anonymous]

Perfect, thank you for the support 🙂