# Planes Z-axis directions

Hei,

Aim is to flip only Z axis the of planes where X and Y axes stay in the same direction. Unfortunately, using the flip plane is still flip X and y axes. what is the fix?
Flip plane Z direction.gh (30.7 KB)

This really isnâ€™t difficult.

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I donâ€™t believe you can flip it like you expect. Rather you need to think about the Z as a negative value if you want the XY to remain as is but move/manipulate the plane in the opposite direction you would provide a Negative component or -x expression to the â€śZâ€ť or â€śNormalâ€ť vector of your plane in any operations you are doing.

Does that make sense?

Alternatively you can use Cross Product with the X,Y vectors of your plane with a negative expression on your cross product output. This will give you the negative Z vector you seek and you can I guess then create a sort of â€śpsuedo inverted planeâ€ť

Now keep in mind thereâ€™s a reason a plane can only be â€ś1 wayâ€ť as you get complicated with neg and pos values when you try to flip only one vector and not another. This is why you should work with vectors in your case and not a plane necessarilyâ€¦ or at least not entirely.

That being said hereâ€™s an inverted fake plane that achieves what you are after, I made the -Z purple to highlight the fact that it is in fact negative and not a proper plane Z positive value.

Or perhaps Iâ€™m overthinking this and you can flip just the Zâ€¦ I donâ€™t think so though.

Graph Space:

Model Space:

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The old â€śRight-hand ruleâ€ť:

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Thank you for the replays. I managed to achieve what I do need by calculating the Dot product of the Z axis and mirroring the geometries that have a negative Dot product value.

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