[A.J]

ok,
1. what happened actually if you apply an opacity map to 3d objects? (by 3d i mean cube,etc. , not cards)

2. what is the differences between camera map per pixels and normal bitmaps?

thanks in advance

[Suirebit]

per pixel mapping doesn't stretch the projected image even if you use low poly geo, otherwise you will have to manually adjust the number of polys to get the desired result.

You actually do apply an opacity map to any geo, however this is done indirectly - usually by the means of using a .tif with a stored alpha channel.

When you project you won't use only cards, that's the most easy situation, but generaly you will have to make at least some low poly geo for your environment, and - if architecture is involved - then you will have a 3d model for sure to re-project on :)