how not to render back faces?

I hope this is the right forum.
Does anyone knows how to tell blender not to render back faces, to render only the faces with normal facing the camera and the faces inverted, not to render them or render them completely transparent?

For instance, if I flip normals of a cube and use this option, I would see only the faces on the other side of the cube, not the ones in front of me.

Or if I use this in arquitecture, allowing me to see what is inside a room from any angle, even if the room is completely closed.

Any help?

And, another question that could also solve this, but that is a question by itself; is it possible to apply to different material to a face, one in each normal?

Like a paper of a book, so I would have one text in one side, and other on the other. Or, in this case, I could have one texture transparent on one side, and an opaque texture on the other.

I really appreciate any help. This is quite urgent for me. If this is not the best place for this question, please, help me ask it where I could get help.

Can’t help you with two textures but by default Blender renders faces as double sided because it is usually checked by default. Uncheck Double Sided in the Mesh panel of the Edit buttons (f9).

I can not find this feature in blender 2.5, but in 2.49, as far as I tested, it will only invert the shading of the object. If the light comes from one side, without the double sided it will seem to come from the other side.

But wathever is inside the object will still not be visible.

well there is a node Z distance that can cut a model in 2 like a plane in 3D

look up in Node wiki pages for this effect

you can also from another point of view use the Alt-B on Alt- B off to cut a scene/ model in 2 but i think this doe snot work in render only in viewport

do you know what i mean here have you ever used this feature in blender ?

you could also if your carefull used the build effect
and stop it at a certain frame i think

but be carefull to enter object in the right order !

happy 2.5

It would not work, because I need this in a normal based effect inside the render. Like a paper, if I flip it, it should disappear. In an arquitectural scene I would need only the walls not facing the camera to disappear, and this might not be forming a perfect plane. Beside, I would have to controll it all the time.

But the main reason I want to use it is to be able to see objects inside an organic form, but still have the faces in the other side blocking the view. An arm, for instance, I have objects inside it that I want to see, and there are also objects inside the chest that I want to see. But if the arm stays in front of the chest, I want it to hide the chest and its object, but not the objects inside the arm.

i think this is difficult to do in blender

you could also control the alpha for each material using IPO curve

but it’s a lot of work !

hope it helps


Not necessarily animation, but I guess I could control the alpha trough the normal.
It is definitely not the ideal solution but it would work, I guess.

If it is not for animation, why the fuss? It would be much less headache to just set up the shots how you want them. Remove faces you don’t want and cheat the lighting if you need to. There are many ways to do that. From your description anyway. Maybe I don’t fully understand.

In this case it is for animation. I did not explain what I need to do right now because it is really complicated to understand.

But it is a feature that is used a lot and has many applications. Or at least I used it a lot in my 3ds max life. The other solutions are much slower and more difficult to do. But since there are alternatives, then it is not such a big problem.