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Thathmew

Problem 3D Doesn't solve

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With all the discussion over 3d vs 2d and what-not I thought I'd bring up some of the issues that 3D doesn't solve or causes. Before I begin I'd like to state that I do believe that 3D is the way to go, and one can check out the game I've developped, Prelude to Darkness, in 3D iso at www.zero-sum.com. I'll start with objects larger than one tile. The _only_ issue thath 3D helps solve here is draw order. It actually creates some other issues. The main issues with objects larger than one tile is their blocking. I.e. which parts of the world space they make impassible. There are a lot of solutions to this, but it's very diffent to avoid clipping no matter what solution you choose. Clipping being when 2 or more 3-D models intersect and portions of them appear to occupt the same space. One of the benefits of 2D is that this rarely if ever occurs. But is clipping a big deal? In terms of game play things function the same even if the graphics get a little odd. A couple of years back at E3 I attended a work-shop in which the developper discussed the issues of going 3D. The number one problem of 3D versus 2D is realism and suspension of disbelief. Basically once you have a problem (like clipping) which occurs in game and obviously violates the physical rules of the real world, you break the player's suspension of disbelief and you can _never_ get it back. 3D actually introduces more of these than it solves. Because the models appear to occupy 3D space the user's inherent expection is to have them behave as objects would in the real world. So to maintain suspension of disbelief one has to code a fairly realistic physics engine which accounts and prvents things like clipping. You also have to keep animations a lot more in sync. Slippage, i.e. when a character's motion does not match their animation creating a skating effect, is much more likely in 3D, rotating people necessitates more complex animations because the closer to realistic you get the closer to realistic the user expectations. Lighting can be a similar issue, in 2D you often don't have lighting, but in 3D lighting becomes much more important because of the users expectation and bad or imperfect lighting bacomes worse than no lighting. Complex physics and lighting models are really the limitting factor these days more than poly-pushing. One of the reasons the most realistic looking games still usually have fewer than a dozen actors on screen at once. One way around these issues is to stylize your presentation. Go for a cartoon look or something that the user won't demand realworld behavior from. Just some thoughts for all those out there working on 3D iso engines. cheers, mat mat williams Lead Programmer, Designer Zero Sum Software www.zero-sum.com Edited by - thathmew on June 27, 2001 12:51:19 PM Edited by - thathmew on June 27, 2001 12:51:54 PM

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I would suggest checking out the new breed of real time strategy games (which have traditionally used iso engines) comming out this fall. They are mostly using 3D iso engines now, and they look fantastic. All of those things you mentioned must have been solved because the 3D engines look as good as their older iso engines.

Possibility

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The new RTS games do look great and they are sure getting a lot of units on screen at once.

There''s been many true 3D RTS''s that have been released to date that have also, IMHO, looked great. A lot of them haven''t really solved these problems, particularly accurate blocking and collisions clipping, are things which have been brought up in reviews as reasons why these might not be as "gripping" as older 2D games. I don''t know. I haven''t found an RTS gripping since Starcraft anyway. And I don''t find that gripping any more either. But I think that''s a personal problem.

From looking at some of the crop of new ones I''m not convinced yet they have solved these issues in an optimal way. But I sure hope they do.

I think all the issues are definitely solvable, just things to be wary of and take into consideration when developping a 3D engine of any sort. Eventually, soon even, we''ll have the processing power to do true volumetric collisions and reactions.

blah, blah, blah,
cheers,


mat williams
Lead Programmer, Designer
Zero Sum Software
www.zero-sum.com

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I get what you are saying and as far as I am concerned
2D versus 3D is not what it it about.

In a 2D environment you still get skating on animation, it
is an inherent problem when you cannot interoplate according
to framerate regardless of what dimension you choose. Skating
however can be avoided in a 3D systems that employ skeletal
characters by using blending and interpolation.

However your point is correct in so much as your visual
system is getting more cues from a 3D projection and thus
your brain is somewhat reluctant to compensate for it when
it is done badly.

Collision detection and piercing is also down to sloppy
coding. Of course when two 2D sprites intersect they take
a drawing order that is exclusive. You will never see part
of an arm jutting through the other characters as you might
in 3D.

With a sufficient bounding box or a collision reaction based upon the object then this could be avoided.

There are many advantages in 3D other than drawing order. You
define one skeleton and can have multiple animations based
upon it. Your walk cycle now consists of a few K and your
character can move in any direction it wants. When your model
is running you can bring it to a halt and perform a skid
animation by just blending between the two.

You can have one texture which is 512x512 and map it to
any object within your world by just setting a few UV's.

You can flip it ,skew it alpha channel it and put multicoloured
light's on it.

You can animate UV's over time to create animation, you can
modify a models vertices over time. The hardware blits this
stuff faster than you can blink an eye and you do not have
to worry about walking under a bridge or having a character
drop down from the sky just because you have forgot the
3rd dimension.

Plus a lot of other stuff.

If you are worried about physics go and look at the Havok
api. Go and download some samples and see what this baby
can do.

I am not interested in 2D versus 3D but Isometric is an orthographic projection. Why not just drop the pseudo 3D restrictions right now.










Edited by - ancientcoder on June 27, 2001 7:55:10 PM

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