Texturing one side

[Rlymoody_O]

I am wondering how you only texture one side of the wall? Or change textures between the two sides?

[NP5]

Faces have a front and a back. Having the back of a face showing on the outside can cause all sorts of rendering problems.
The course on the corridor mentions having to make the ‘outside’ of the faces look inwards so they are the visible textured interior wall.

There are ways to have different textures on the back face, but it is rarely used and not simple. Almost everything has real thickness, so the inside is never seen. Games for example mostly use ‘backface culling’ making the back of a face transparent.

[Rlymoody_O]

Thank you for the explanation. I am building worlds in VR and was wondering how to make my building walls different textures because those are seen. Uploaded through Unity. Thanks again.

[Rlymoody_O]

I found a video. That is way too involved for me right now. Maybe later

[FedPete]

Yes, faces do have a different back and front side!
That’s is why Blender has a ‘normal’ pointer (not seen by default) to indicate the front side of a face.
The (old?) 3D specification is that back faces can not be seen or rendered. Which is logical from a 3D render engine software perspective. A back face can never be seen. So why bother rendering it.
Do remember that a face doesn’t have a thickness! it is zero! infinity thin.

A solid object, like a cube, has 6 faces, all normals pointing outwards, showing the visible side of the face. But you will never see the backside of the face. It’s not rendered and therefore it’s invisible, transparent. So why spend computer power on something which can’t be seen. While we have very fast computers nowadays, in the past it helped to have fewer faces to calculate for. This is still the case for game engines.

But then there is Blender!
Blender does show the backside of a face. Because it helps you in the design process. You can switch it off, then it will confuse you in all possible ways, even at render time. The backside of a face will not block the light anymore, because the backside of a face does not exist or block the lamplight.
That is why Blender has by default backfaces visible (active) and some game engines not.

To export objects, it’s important to see how those face normals are pointing? Always towards the camera!

[Rlymoody_O]

Thanks