2.81: Symmetrical loop cut?

I’m used to modeling in Lightwave, and there you can Cut on both sides of a model in Symmetry Mode.

This doesn’t seem to be the case in Blender 2.81. Symmetry seems only to support transform, rotate and scale, and not even Extrude.

Is that accurate?

If you ve got symmetry modifier on your object it should work. Normaly

Modifier you’re looking for is mirror modifier. As far as I remember, LW supported only X axis symmetry, but with Blender, you can have this across 3 axes.

The 3 axis thing seems pointless if you can’t do extrusions.

You can, with the Mirror modifier as two people have already suggested. Edit mode symmetry is limited to transforms.

They are talking about using the mirror modifier, I think you’ve confused that with the mirror option in the tool tab of the sidebar:

You can use any command or tool you want when you use this modifier, but that option in the n-panel is only good for symmetrically moving vertices around. You’d only use that tool option if you want to make some symmetrical adjustments without having to cut your mesh and add this modifier.

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The mirror modifer is great, but is there any mode that allows MOSTLY symmetrical work?

IOW, a tool that asks “Is there a vertex corresponding to the current vertex on the other side of the mirror plane? If so, transform with the current tool.”

Like, imagine you’ve got a spaceship that is 90% the same/symmetrical on both sides, but one side has a sub-assembly that doesn’t exist on the other side. TMK, the Mirror Modifier would generate the unwanted sub-assembly.

If the Mirror Modifier be limited to specific Vertex groups/Face maps, that would do the trick I think.

Typically you’d model all the symmetrical features with the mirror modifier on first, then apply the mirror and add any non-symmetrical stuff.

Alternatively, you could try selecting all the features that should be symmetrical then use the symmetrize command (Mesh menu > Symmetrize) to create a symmetrical copy of those features on the other side.

thanks for your reply: APPLYING is what I’ve been doing, but it does seem to lock the model in at a certain point.

From everybody’s replies (Thanks!) it seems that the functionality I described above (90% symmetrical modeling) isn’t currently available. Perhaps it’s too niche, or maybe someday someone will write an addon.

Apologies for beating this horse: it’s just that every apps’ “symmetry function” seems to work slightly differently, and some features that are desirable in some cases are not present universally.