Why backface is visible?

Hi All,
I am new to Sketchup.
I have stairs and on one of the step I have applied the material on backface. Please check the screenshot

Why the material is visible from front side ?

If you right click the face and reverse it, the front face will be upwards. I’d also recommend to shoe the Style toolbar (should really be called Face Style) where you can change to Monochrome mode to easily see what side of the faces are showing. Also, you don’t need to have the Getting Started toolset displayed when you have the Large toolset.


More effective than relying on Entity info - which does not actually reveal orientation if both faces have the same material…
Change to View > Monochrome, using a Style with a distinctive back-face color.
Any wrongly oriented faces are then easily seen and fixed by selecting them and using the context-menu > Reverse.
Apply your material only onto the front of all faces.

It is particularly important to get your faces’ correctly oriented if you are using geometry for 3d-printing, or you are planning to use a 3rd-party rendering program - because most of them ignore materials of back-faces and substitute black/white/transparent materials…