Hello, I want to know more about isometric games: If I want to make a 3D isometric game with opengl for example. What are the advantages to go isometric? for instance: - About speed (fps) ? - Memory for terrain ? - Ease of programming ? - Ease of using for the player ? - ............. The disadvantages ? I really want to know! Thank You Renran

Advantages:

Speed - if you are working in OpenGL, I don't think orthographic(sometimes also called isometric) projects are any faster or slower than perspective projections, but I could be wrong about that. If there is any difference it is probably pretty minor.

Projection is kind of superfluous here though. I suppose you could do a perspective projection with 3D, tile based game, but everyone I have seen has been isometric (Panzer General III). I think some of them use isometric but fix the camera so that you can't rotate it. (You might still be able to zoom in and out though), so its kind of pseudo 3D.

Using tiles does make alot of calculations simpler though, especially for things like collision detection (which is trivial for tile based).


Ease of programming - tile based engines are much easier to program (see above)

Ease of use - I believe that tile based games are much easier for their users to comprehend gameplay mechanics, given equal complexity of the rules.

Memory for terrain - with a tile engine you typically store the type of terrain for each tile. If you don't have a tile based engine, I'd imagine you would store a bunch of bounding polygons for the different terrain types. So non-tiled based way might actually use less memory. But with memory on systems in excess of 1 GB, it really isn't an issue. Most maps would probably fit under 1 MB. Unless you want to do something crazy like trying to model the entire world at 5km/hex (I am actually trying to do this!), this really isn't an issue

The disadvantages:

Tiles are less realistic than some type of free movement system. For example, if you an artillery unit that has a certain range, the tile system makes its effective range unrealistic in certain directions. This is not a big problem when the ranges are small (say, no more than 3 or 4 hexes), but when the ranges get large, the effective range isn't truly "circular" as it should be. This is especially a problem for things like air movement.

And if you go with square tiles, you have to deal with the fact that the movement is distorted along a diagonal. So if you moving diagonally is a distance of sqrt(2) * the distance you would move side-to-side. I haven't seen any system that uses square tiles that tries model this correctly. At a small scale, where you can only move a couple times per turn, it doesn't make sense. But even using a hexagon tiles, you don't get away from the circular range problem.

I actually don't know of any turn-based strategy games that used anything other than tiles, whether 3D or not. (e.g., PGI and II were 2D, and PGIII was 3D, but it was still tile based.) That would be more the real of RTS. (Actually, I think some RTSes still use tiles, you just can't see them)

Snowdog,

Thank You for Your very good explanation about isometric games.
I do know now what can be done with isometrics.
I will try to learn the basics and look what happens.
Thanks a lot.

Greetings,

Renran