Archived

This topic is now archived and is closed to further replies.

Maximum possible level size?

This topic is 5885 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

If you intended to correct an error in the post then please contact us.

Recommended Posts

Hello everyone, Can anyone tell me what the maximum size for an outdoor level is currently? I''m impressed with Operation Flashpoint''s 10 km by 10 km islands. That''s the biggest I''ve seen to date. Is it possible to go bigger? Could you make a planet (albeit a puny one) tens of kilometers in diameter? Would all of it have to be loaded into the 3D card''s memory or could it be loaded and dumped dynamically as one moves across the globe? Couldn''t the program - ''knowing'' which way you''re heading - load the scenery just before you got to it; over and over again as you moved about? Maybe my question makes it obvious that I am not yet a programmer. jelb

Share this post


Link to post
Share on other sites
Well, indeed I am working on such a thing at the moment. It is rather difficult though. I already managed _very_ small planets, with a radius of maybe 100km, and no objects on it. It is just some round thing, that, when you come close turns out to be a rather hilly asteroid. The problem is that you cannot store that much polygons in RAM. So I use some algorithm that calculates the needed polygons at run time. Even though, it is very buggy yet, and crashes rather often ;-)
If you want to read more about this, you should search "CLOD" and "ROAM". Those algorithms reduce the number of polygons to render at run time. That means, polygons, that are far away, are put together to just one polygon. This way you may render objects consisting of millions or even billions (and possibly more) of triangles in real time.

Share this post


Link to post
Share on other sites
There are many tile-based RPGs that have huge areas of outdoors. In 3D worlds, there''s no reason you couldn''t have a much larger outdoor area than 10km. Indeed, there''s no reason, apart from disk space, as to why you couldn''t model the entire Earth at a high level of detail.

One thing about large outdoor areas is that they''re usually boring. Creating big hills is easy, populating them with interesting things to do isn''t so easy.

Anyway, you couldn''t load them all into memory. You can use the CLOD or ROAM techniques Chock mentioned, or you can use depth cueing to fog out the landscape over a certain distance. By dividing the landscape into blocks (of say, 100mx100m), you can load the blocks the player is in, and the adjacent blocks. When he moves to a new block, unload those blocks that are no longer visible. This allows for smooth transitions between blocks, particularly if you load the blocks in a background thread.

If you want to generate landscape at runtime, look for information on Perlin noise and fractal Brownian motion (also called fBm). These are well suited to use with ROAM (and, I assume CLOD).

''Nuff said. I''ll enjoy watching you live, demon.

Share this post


Link to post
Share on other sites
Chock, Mayrel,

I am encouraged by your posts and will check out the techiques you both mentioned.

Now I wonder why I've never heard of a 3D space sim that allows a full descent from orbit to a planet's surface. Every one seems to use cut scenes.

Battlecruiser 3000AD comes the closest that I've seen. You descend quite far until the planet fills the screen and then there is a short cut scene that puts you in the air quite close to the surface. The planet seems large too, judging by how far I've tried flying. I haven't flown completely around it though.

The point is taken about large barren levels (or in this case an entire planet) being boring. The only way it wouldn't be is if players could build bases and such; and use scanners to detect signs of civilization.

jelb

Edited by - jelb on October 30, 2001 11:32:50 AM

Share this post


Link to post
Share on other sites
Elite and Frontier Elite allow you to land directly on planets. They don''t look particularly nice, but they do.

If you''re looking to model planets for a space-sim, I''d definately look into fBm, it''s the best technique available that doesn''t need a super-computer or a RAID device.

Frontier copes with boredom by making it part of the game: you can fly around at random on a planet looking for mines to steal, but you''re very unlikely to find one, since the planets really are as big as planets, and the mines are small.

Frontier also has ringed planets, orbiting bodies, and your ship is effected by gravity (if you''re good, you can put your ship in orbit around a planet). If you''re making a space sim, I heartily recommend you try it out so you know how to do it the right way. If you''re interested, and you don''t have it, you can get it legally for free - there''s a link at www.frontier.co.uk.

''Nuff said. I''ll enjoy watching you live, demon.

Share this post


Link to post
Share on other sites
quote:
Original post by Mayrel

If you''re looking to model planets for a space-sim, I''d definately look into fBm, it''s the best technique available that doesn''t need a super-computer or a RAID device.

''Nuff said. I''ll enjoy watching you live, demon.


Yes I''ve heard the, uh, legend of Elite. Maybe I will try it. BTW there''s a site (http://www.theunderdogs.org/) that has all kinds of old classic games that have been released to the public domain... and yes they certainly mention Elite there - highly.

That fBm terrain rendering technique: Does it render the exact same terrain if you leave an area and return to it? Buildings and all? Probably it does but my (currently) non-programming mind can''t imagine the math that must take.

jelb

Share this post


Link to post
Share on other sites
Generating the exact same terrain or city or culture or whatever from a seed is not a problem. The challenging problem is to create the illusion of change from one time to another. Not just the changes the player makes, but the evolving changes of the area itself related to environmental factors, and other people making changes.

Examples of changes from one time to another include the fact that person A has now done something which changes something or some major event completely changed the environment and everyone reacts to that.

If, you as a player visit a location and then revisit that location later, you want some consistency between the two visits.

Share this post


Link to post
Share on other sites
Guest Anonymous Poster
quote:
Original post by bishop_pass
Generating the exact same terrain...


Point taken. Right now it''s enough for me to know that planetary size levels are possible. If, after I learn to program some, I''m still stuck on the idea I''ll tackle the consistency issue then. Gotta learn to walk... or maybe in my case crawl... first though.

jelb

Share this post


Link to post
Share on other sites
quote:
Original post by bishop_pass
Generating the exact same terrain...


Point taken. Right now it's enough for me to know that planetary size levels are possible. If, after I learn to program some, I'm still stuck on the idea I'll tackle the consistency issue then. Gotta learn to walk... or maybe in my case crawl... first though.

jelb



Edited by - jelb on November 1, 2001 1:14:02 AM

Share this post


Link to post
Share on other sites