I was wondering this because I have sort of complicated objects that I don’t want to manually go through to get the normals to face the correct way. I just used the “Twoside” option on all of the faces instead.
But when you have the option “Twoside” selected for a face, does it take up more processing power than just a 1 sided face? I’m starting to think it does because even with the newest Apricot build, the framerate starts to lag at a little over 20,000 quads. That’s pretty low for Apricot. What I’m thinking is that when you select Twoside, its practically the same as doubling the poly count. Is that true?
yes it is true.
that kinda sucks
Yep. Enabling twoside doubles your poly count.
Keep in mind that you can use the recalculate normals (ctrl-n for facing all faces outside and ctrl-shift-n for inside) to automatically face the right way. Also, if you use the twoside function the faces won’t correctly respond to light if they’re still facing the wrong way. It pays to be efficient – take the 5 minutes to fix the faces.
I think the easiest way is to just be careful while you’re modeling. One thing that causes the normals to flip is beveling. If the lines intersect, the newly made faces will be flipped. I think boolean modeling may do this to, but I wouldn’t advise that anyway, as it can add a lot of unnecessary vertices.
unlike many people seem to think though, twoside does NOT double the poly count. however, it increases the load the gpu has to do;
normally, when a face is pointed away from the screen, since it would be on the far side of the model, it is not rendered (because it’s a wast of resources, and unnecessarily slows things down). if there are see through parts of the model or your normals are wrong, the wrong faces will be in the camera’s field of vision but facing away, and thus invisible. however, if you want to model something like, say, a sheet of paper, you can enable twoside- if the plane is facing away from the screen, it will still be rendered. if the face is in a circumstance where it should not be twosided (say, a normal part of a model) it will take rendering power when is shouldn’t.
if the normals are facing the camera, though, it being twoside will have no effect on framerate.