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How do I make the faces I am using for the leaves of the tree I am making double sided? Currently only one side appears, while looking at them from a different angle they disappear. The only solution I have read so far is to duplicate the face and then flip the normal so you essentially have two faces back to back, but I'd rather not do this because I am trying to keep my poly count low, these trees are for a game.

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3 Answers 3

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2.8

In Blender 2.8 double sided normals are always-on by default, but if you want to turn them off (e.g. for export) you can enable Backface Culling in your material's settings:

r 2

Note that it's up to the exporter to respect this setting, so this may not work for every format/exporter.

2.7

For a game, I think that duplicating and flipping the normals is probably the best way to go.

Rendering double sided faces real-time can be very expensive, often more expensive than drawing the extra geometry. Of course, it depends on the engine, so the best thing is to try it and see which works better.


Enable Double sided in Properties > Object Data > Normals:

enter image description here

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  • $\begingroup$ Found this link katsbits.com/tutorials/blender/… to describe how to flip normals $\endgroup$
    – ala
    Commented Jan 14, 2017 at 6:03
  • $\begingroup$ "Properties > Object Data > Normals" I can't find this... $\endgroup$
    – RollRoll
    Commented Feb 10, 2017 at 23:08
  • $\begingroup$ @ThePoet I've added a screenshot $\endgroup$
    – gandalf3
    Commented Feb 11, 2017 at 1:19
  • $\begingroup$ It's not there in blender 2.8 $\endgroup$ Commented May 30, 2020 at 16:39
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    $\begingroup$ @MichaelCole Thanks for the heads up, I've updated my answer $\endgroup$
    – gandalf3
    Commented May 31, 2020 at 2:50
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For troubleshooting it is also helpful to toggle backface culling in viewport shading options here:enter image description here

This won't create any faces, but makes it easy to see where they are missing/flipped.

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Press E to stretch the selected in edit mode. Once stretched to the minimum amount possible select all faces and if there are any discrepancies press Ctrl + N to make Normals Consistent.

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    $\begingroup$ That's exactly what he didn't want for the sake of low poly. $\endgroup$
    – Grimm
    Commented May 18, 2018 at 9:08

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