the q3 engine is fine. but for the next version or trem 2 we should make it a stand alone version of halflife 1, you can do the same stuff as in the q3 engine and there are some better and newer functions and the maps that are used in trem will work in half life
Quake3 is the better engine nowdays.
Half-Life1? its that a joke? Half-Life 1 is like Quake1. The problem with the Quake1 engine rendering is that was designed FOR SOFTWARE RENDERING ON A 486!. This mean Half-Life1 is unoptimized for hardware rendering on pentium.
Quake3 whas a redo, with hardware rendering. Its the most perfect you can get from rendering optimization and design.
Its Doom3 better?
Not!.
Doom3 and these engines are designed with tradeoffs for shadow volumes, and other lighting stuff. These lighting stuff is good for singleplayer games, but I a gimmick on multiplayer games, and make the engine lotsa slow. So only a limited num of users is posible ( 4 players on the original Doom3 game!!)
Conclusion:
Quake3 is the better engine tecnically, AND IS FREE!!.
About Half-Life1:
Its not free, and you can't distribute it. To make standalone games you need distributions rights over the engine, and Valve will not able that.
Lets wait 7 years. Maybe Id will release a new engine Doom3 based (maybe not). The hardware will get better, and will be posible to render shadows withouth much overead. THEN a doom3 engine will be better for a tremulous alike standalone engine.
Half-Life2 can also make for a good engine for a Tremulous mod, but will be lest powerfull at rendering. This mean simpler maps, so less hidden areas for aliens. Anyway Its not a candidate for standalone becasue is not free and never will be ( But the source its out here, leaked, and you can read it: Its Quake1 based )
Theres another element interesting here:
dpmaster, originally designed for DarkPlaces (I guest..DP =darkplaces), theres TONS of free games that use that feature, and is reallly needed for multiplayer games to work nowdays. DPMASTER is free, modable and very flexible. Valve can shutdown WON, but no one can shutdown DPMASTER.