Noob question - Creating backside polys of an object?

[Mik2121]

Hi there. I'm a bit noob when it comes to designing stuff for games but I started recently my game design course and we are doing a 3D game now. I'm the stage designer but I have a question I've never ever wondered about!:


Is there an easy and fast way to create the backside polygons of an object?. I'll explain myself better with this picture of the object I'm currently doing:

http://i178.photobucket.com/albums/w251/KimHaeChul/StoneBase.png

I screen-capped straight from 3DSMax. Now, you can see in the crystal thing that it has opacity set to 50% (I will have to change it by adding an alpha layer by the time I export it to the game, but that's not the point now), and you can see the background. Now, when I watch it on the view-port, the backside shows up and it's all good, but when I render it doesn't show them up, and therefore in the game won't show up either. So, is there any way to create those extra polygons with a couple clicks, or I'll have to copy everything, flip it and all that? I honestly am not really sure about what would be the ideal workflow for this kind of stuff.

Thanks a lot and sorry for the noob-ish question!.

[Japhir]

In 3ds max check "double sided material". don't know if it works for a game engine though ;).
if not, just copy it and flip the normals.

[BigJohn]

As far as the render goes, like Japhir said, you want the material to be 2-sided. Also, right-click the object, and hit Properties, and make sure Backface-Cull is off (unchecked).

You definitely don't want to duplicate all those polygons and flip them. That's a waste of triangles.

It's really up to the shader and the engine that you're using, but you should be fine. As long as it's a double-sided material, and there's no Backface Culling, it should be fine