Question About The D3 Level Size And Exteriors

[jlkenyon]

As a potential future level editor, I had a few questions about the D3 engine. I have never played the PC version of the game (for lack of a qualified video card) and have only played the XBox version (I will probably be boo'ed off the boards for that confession).

 

So far as I could tell, all of the levels were fairly small, much smaller than most of the levels in thief 1 and 2. I was wondering if this was a constraint of the Doom3 engine, or if this was a product of the meager RAM in the standard XBox (I have heard that the levels in thief 3 were broken up into small areas because of the memory limitations on the XBox version). I suspect that any modern engine, especially such a professional one as the Doom3 engine, could handle any concievable level size. I am concerned because the larger exterior maps in Thief (notably the abandoned old quarter in Thief 1) seem to be much much larger than the levels in Doom3 were. Has anyone tried making a level as large as any of the Thief levels? Is there any noticable performance hit as compared to many small rooms?

 

This leads me to my next question: exteriors. In doom3, all the levels take place in fairly confined spaces (as per the nature of scary games). The only case I can think of that involved rolling hills was the terrain outside during the monorail ride. Fortunatly, Thief tends to have the same sort of enclosed areas in many levels, but it did have large open spaces as well (the Bonehoard was all underground, but still had some *huge* open areas. Now that is the kinda burial I want!). I was wondering if the Doom3 engine's brute force method for rendering visible sectors took any performance hits in such vast open areas?

 

Sorry to ask such simple questions, I suspect that these were all taken into consideration when the Doom3 engine was decided upon, but my experience with D3 has raised a few doubts. (I hope this is not a repeat question, I searched the forms and found nothing relevant). Normally, I would just make a few test levels and run some benchmarks myself, but with just a GeForce4 MX, the doom3 demo runs about about 1fps, which makes my eyes bleed.

 

Keep up the good work, and thanks for keeping the Thief legacy alive!

 

John

[SneaksieDave]

Boo!

 

Seriously though, don't worry overmuch. D3 has gobs and gobs of rendering power, indoors or out, big or small. Outdoors, be careful with your per-scene portal counts, build it smart, and don't throw a bunch of inefficient lighting all over the place, and you can render a decent sized city. Indoors, use your portals well, and you can probably build the whole NYC subway system or the Hyatt Regency hotel of your choice.

 

I have no doubt a level the size of original Thief missions is completely do-able with good design and proper use of portals.

 

In fact...

[OrbWeaver]

It's all a question of detail. Thief 1 and 2 maps were very un-detailed by modern standards, therefore they could be made very large without too much memory impact. Once you start adding the detail expected in modern games the memory footprint increases and the effective maximum size diminishes.

 

This is a trade-off you have to deal with for any engine, although some engines have specific optimisations for certain kinds of scenery (e.g. Far Cry).

[sparhawk]

Currently we can not know which level isze is realistic. The reaons is pretty simple. We run a lot more code per frame then Doom 3 does. So enginewise the answer is: Yes, you can do pretty big levels, even with a lot of detail. It remains to be seen, though, how much this will decrease because of soundprop, lightgem and more sophisticated AI. Hoever this does not mean that levels will become as small as TDS levels. Personally I think levels at the size of original Thief 1/2 missions should be possible if properly designed. Even in T1/2 missions the levels were pretty big, but in most cases you could not see so much as you might think you could see. Often this was well hidden, so that you had the impression you saw a lot more then you actually did.

[Kristus]

Well, I can't speak for Dark Mod. Since it's obviousl quite different from regular Doom3. But the maps we make for Doom3 in Doom3: Phobos are ranging between 10000-17000 brushes so far. But I've seen a map that used 20k brushes. So as for level size. You should be good.

[bob_arctor]

Surely the detail point doesn't really work because computers have advanced since Thief II.

So saying "the amount of detail in TII is the same as Doom 3 but in a smaller denser space" and that it's an engine trade off can't be right: since then PCs are more powerful so we can have lots of detail and large space engines.

[sparhawk]

Of course computer became more powerfull, but on the same vein engines also become more powerfull. For a given area, an engine has now to handle more data then for a lowdetail area a few years ago. So the assumption that, because computers are now faster they should be able to support bigger spaces, is not neccessarily true because this depends on many factors, not just speed. But I would say that Dark Mod levels will definitely be bigger than TDS levels with the same amount of detail.

When we get the sourcecode for Doom 3 we can even make bigger maps, because currently we have to do stuff that is rather performance intensive in a way that it is not very efficient. When we have the source, we can make some algorithms much more efficient then now which translate to more detail or bigger maps.

[bob_arctor]

Are there any processes in the rendering you can turn off for speed gains?

 

I don't know, some post pixel effect things that are great in a space station but in a mansion can be turned off and replaced by good texturing?

 

Lots of people don't care about TII graphics if there is good texturing and architecture, it covers up for a lot, so maybe you can do the same with Doom?

 

As long as it's bigger than TDS though .

[sparhawk]

As long as it's bigger than TDS though .

 

This will be a certainty.

[OrbWeaver]

Are there any processes in the rendering you can turn off for speed gains?

 

It is not so much the rendering performance as the memory usage that is important. You could always make bigger levels by having simpler architecture and lower-res textures, but that would look rather poor by comparison with today's games.