Hack 100. Create Your Own Level Mods


MrMurder is one of the most active and prolific members of the Halo 2 modding community. If you've ever wondered what a modder is thinking when he creates a modded level, then you will enjoy reading through this overview of the process.

The thing that makes the levels fun for me is the weapons. I feel that good, balanced weapons make a level enjoyable to play and give it longevity. This is why I always go into as much detail as possible for the projectiles. I want them to have high-quality appearance, impacts, explosions, and damage effects.

For Undeadlong [Hack #90] it was decided early on that the level would have a super weapon. I decided that it should be hidden somewhere as a reward for the explorers among us. In other words, it would be an Easter egg.

I wanted to import the Scarab beam from the single player campaign into a handheld weapon; this had never been done. I used ADI [Hack #50] to save the relevant meta for the Scarab beam and noted down the size of each piece of meta. I had to do this because you can only inject metadata over larger pieces of meta. In addition, you have to select pieces of meta that the game is not using. If you try to use something that the map needs, it will cause a crash when the game engine tries to find the data.

I started on the main Projectile [proj] by injecting the Scarab beam projectile over the Plasma Rifle bolt projectile. Next, I used the ADI dependency swapper to set the bolt as the Battle Rifle projectile. From there, I opened the original Scarab beam in the New Mombassa level and compared the meta for its projectile with the one I had injected into Headlong. This allowed me find the other pieces of meta that it needed to work properly.

From there I injected Beam [effe], the Beam Detonation [effe], Beam Pulse Effect [jpt!], and for the damage, [mgs2]. The Light Volume and the [cont] Contrail also had to be injected. Of course, all of these tags had dependencies of their own. Working with dependencies is like exploring tree roots. You have the main projectile or weapon as the trunk and from that, all the other tags split off and make more roots. Each root has its own dependencies that all need to be followed to make the new projectile work in the game. If you miss a vital one, it's not going to work out too well.

12.12.1. Undeadlong and the Hive's Weapons

There are many low-level details involved with creating the weapons for some of my modded maps.


The Photon Rifle/Human Sniper Rifle

I swapped the Sniper Rifle bullet for the gauss hog projectile and started to swap out some of the impact effects so that the round would pass through players and vehicles without stopping, but still do damage to everything that it went through. Next, I took the zoom down to a single 4x option. I did this mainly to balance the power of the projectile with the skill needed to use it.

Next, I started work on an explosion. Using the Meta Scanner in ADI [Hack #50], I selected the Scorpion shell explosion and I started to swap some of the original partial effects [prt3] (what's generated to make an effect like an explosion visible) and the [pmov] (how the prt3 reacts in the air when it's produced like a smoke cloud or metal chips) for different ones. I had to do this one at a time. After each change, I tested it out to see how it looked in-game. This process took a long time.

I had to null out some metadata to make the explosion less draining on the game engine and to prevent lag. I did this while still trying to keep the right look for the projectile I had in mind.


The ION Rifle/Covie Sniper Rifle

I found that the Wraith mini gun bolt (the little automated turret) was only used in the single-player campaign. Since it had not been included in multiplayer, it gave me a whole projectile to swap in. I upped the speed of it in the ADI Tag Editor and added the Needler super explosion to the end of it.

I then used the same method detailed in the human Sniper Rifle to modify the explosion. I wanted it to be punchier and smaller. I also increased the weapon's ammo and reduced its overheat in the Tag Editor. This allowed me to give it the same number of shots before overheat as the human Sniper Rifle fires before it has to reload.


The NecroScorcher/Sub-machine gun

Something people really wanted was a flamethrower, but it was difficult to do without causing some serious lag issues. In the Undeadlong version, I was unable to get a visible contrail on the flamethrower but in The Hive [Hack #91] I worked it out and we had a custom made contrail that worked really well.

The flamethrower's fire effect is the Rocket Launcher explosion with some [pmov] and [prt3] swapped for fire and the rest of its tags nulled out so that only the fire and smoke part of the effect is generated on impact. This was still a little laggy, but it was the best I could do at the time. The flamethrower range is short and the damage is the same as someone duel-wielding Submachine Guns.

By the time I had got to The Hive, I had managed to get a contrail added to the projectile by swapping an existing tag from effe to cont this worked well. In terms of visual effects, a custom bitmap was made by Swese and injected over an internally referenced one. This meant that it didn't have to be edited in the mainmenu.map file or shared.map file to work.


Decayer/Needler

I started by increasing the speed of the needles to be more effective and gave the weapon a faster rate of fire. I then swapped the light tag for that of the Plasma Pistol to give it the green decayed look on the needles and edited the contrail to be longer lasting and change color in flight.

By increasing the projectile's homing ability in the Tag Editor, I made them bounce back at the target even after they had missed and ricocheted off a wall or vehicle.

The fun thing was making the light brighter. If you are struck by one on your head, they blind you. To balance them out, I lowered damage. It's not a killing weapon, but it's great in combination with any other duel-wieldable weapon. The finishing touches were a different firing effect (I used the covie carbine) and the sound from the same weapon.


Smart Cannon/Battle Rifle

There wasn't really a whole lot to do here since I was trying to maintain the theme of distinctly human projectile-based weapons as opposed to plasma or energy-based for the zombies.

I added a fourth shot to the burst (weap tag) and configured the impact effect to use the Gauss Hog impact sparks with a modified explosion the [deca] or bullet hole was large and when concentrated, caused some serious framerate issues.

I actually have a new model ready for importing instead of the current Battle Rifle, but without a program to do this with, it's not yet possible.


Toxic BioBeam Rifle/Brute Plasma Rifle

I swapped in the Brute Plasma Rifle under the [itmc] item collection tag so it would spawn instead of a normal Plasma Rifle. I then swapped in the Spectre's turret beam since it bounces off certain types of collision models and still does damage.

Then in the [proj] tag I swapped the Spectre beam's contrail to the Wraith mini gun bolt and added the bugger's blood splat as an impact effect. This gave the beam the organic feel that I was after.

Next, damage was adjusted and the projectile speeded up from 16, which is the original Brute Plasma Rifle's bolt, to 400 (the magnum speed). This added a much needed balance between the two guns. After that, all that remained was to adjust the over heat and ammo capacity, and it was done.


Viral Cannon/Covie Carbine

This is the zombie equivalent of the Battle Rifle. First off, I swapped in the Plasma Pistol-charged bolt since it had the green blob effect almost done for me.

I swapped the blob's lighting to the Brute Plasma Rifle's red streak and then increased the speed to be fast but not so fast that you couldn't see the projectile.

I wanted an acidic feel to the impact effect, so I swapped the charged bolt impacts effects [pmov] to heavier ones like stones and rubber, thus giving the [prt3] a splash of liquid feel rather than just floating off like steam or smoke.

However, the damage metadata for the Plasma Pistol-charged bolt had to be swapped since its damage (however low) will always remove the player's shield in a single shot. I swapped this for the normal Plasma Pistol bolt and the impact explosion for the Brute Shot grenade. To finish it off, I gave it the four-shot burst of the Battle Rifle and re-added the Carbine contrail with a bigger and more defined contrail bitmap.


Toxic Shot/Brute Shot

I added a simple contrail to the projectile [proj] tag and then added the Banshee bomb explosion to the impact. Like the Viral cannon, I swapped the [pmov] about to give the detonation a more liquid feel. The nice effect on this weapon is the screen shake on impact.

When the [jpt!] or damage effect tags are in the Tag Editor, there are three fun options to play with:

  • Shake duration = how long the screen shake lasts

  • Shake rotation = how far your screen moves

  • Shake movement = left, right, up, and down

By editing these tags, I gave the grenades an interesting effect: When directly struck by one of the grenades, the impact will knock a player's field of vision off center. This will completely disorient him for several seconds. Since the weapon has a clip of just eight rounds, it gave the weapon a cool edge.


Multi-Launcher/Rocket Launcher

The Rocket Launcher was given a two-shot burst and, to reduce the lag issue on firing, the rocket contrails were removed.

I'm still not that happy with the impact explosion, but since the release of The Hive and my work on the next mod for Foundation (called Out-Break), I have created some better effects for explosions.

The damage was edited to make it balanced, requiring at least four rockets to kill a target. The clip was increased to six and holding ammo [Hack #58] to 36.


Viral Blade/Energy Sword

This was the only weapon used by the undead in the original version of the Dawn of the Dead game and is always selected as one of the starting weapons for the game along with the Shotgun.

I went to the [jmad] JMS Animation Graph and swapped the sounds for melee, sword activate, and lunge for some of the Elite screams. Each time the sword is swung it screams this can be fairly unnerving to players close enough to hear it.

Then in the [mode] Model tag, I swapped the shaders for the whole weapon for the teleporter energy effect. This gives the blade its green decayed look, which matches the ongoing theme of the level.


Shotgun

I decided to alter the Halo 2 Shotgun. Using Halo map tools for Halo 1, I used the Halo 1 shotgun's spread for its projectiles and then gave it no minimum and maximum. This means that the weapon fires in a constant pattern. I also added force [Hack #59] to the impact giving it the ability to push vehicles and opponents back when shot within the limits of the physics described in the Screamer grenade section.

From there, the new Shotgun was born. The new version is more like the Sword a staple in defense against the hordes of the undead.


Screamer Grenades/Plasma Grenades

This particular grenade was a lot of fun in my Halo 1 NightWinder mod, so I wanted to bring them into Halo 2. I used the Plasma Pistol firing [effe] meta to inject the Wraith Mortar [effe] so that when the grenade is thrown, it would generate a bigger in-flight effect. I used the Tag Editor again to swap the plasma effect of the mortar with a fire effect and the appropriate [pmov] to turn a thrown grenade into a fireball. The model swap was in the [hlmt] object properties for the Oddball skull. Then in the [lsnd] looping sound tag, I swapped the normal fizzing sound for an Elite's berserk scream.

To balance the grenades, I increased the force of the explosion so it would throw players up in the air on detonation. I also dropped the damage down so that it requires two stuck Screamers to finish off someone.

One of the biggest problems with modding Halo 2 was the physics. It turned out that only the host would experience the force of a projectile like the Screamer grenades. If another player was stuck with one, they would not be thrown around at all.


Fragmentation Grenades

I simply made the explosion bigger by using the Tag Editor to swap some of the [pmov] and [prt3]. This gave the explosion effect more smoke and flying dirt. The damage remained unchanged.

12.12.2. Vehicles

So much for the weaponry; next up were the vehicles.


Undead Hog/Spectre

In Undeadlong, I attempted to make the fully automatic Spectre cannon fire single shots. The idea was to make the weapon more akin to the Gauss turret. However, after play-testing the Undeadlong map, I moved away from this idea. When it came time to create The Hive, I went back to the rapid fire and toxic effects.

The closest thing to what I was looking for was the Hunter's Particle Fuel Rod Cannon, so I imported that into The Hive the same way as detailed in the projectile creation discussion, earlier in this hack. I also toned it down severely to balance it with the Gauss weapon.

During play testing, the firing rumble it created in the controller was so bad that it broke HuMpY's controller; it had to be toned down.


Using the [vehi] plug-in for ADI [Hack #50], I increased the Spectre's handling and boosted the speed to match the changes made to the Gauss Hog.


Gauss Hog/Warthog

The control of the Hog was the first thing I tried to alter. I found that the speed was pretty spot-on. Again, the [vehi] plug-in for ADI [Hack #50] was all I needed, as well as some playtesting to make sure it wasn't over the top.

The projectile I swapped for a Scorpion tank shell in the [weap] tag. Then I opened the [effe] tag and selected the shell explosion in the Meta Scanner, and began swapping its dependencies to create a new explosion for the impact.

After that, I put the damage back to that of the normal Gauss Hog projectile and removed the explosion radius so that the weapon would only damage what it actually hit not what was near the impact. That would have been too unbalanced.


Scorpion tank

I hadn't included the Scorpion (or scorp) in Undeadlong because I had used up some of its meta to inject the Scarab Beam. However, for The Hive I had gotten to grips better with the map structure and because of the sheer size of the level, I decided to include the tank.

I simply saved and injected another Rocket Launcher projectile into the level and swapped that for the scorp's shell. Then I increased its shots per burst to five and reduced the damage of the rockets for balance. This gave the driver of the tank the option to fire a concentrated burst of all five at one spot or to spread them over a few meters.

For the secondary gun, I added a simple impact effect to its [proj] meta so that it caused a small explosion on everything it shot. Then I increased its rate of fire slightly and reduced its damage.


Wraith tank

The Wraith was a difficult vehicle to mod well while maintaining balance. Like the Scorpion, it's a behemoth and very hard to kill with its unmodded weapons against you.

With the undead theme in mind, I modded the [weap] to fire a burst of projectile rather than just a single mighty blast. Then I swapped it to be a second saved and injected the Brute Shot grenade over the unused Covie Carbine slug. I used this one because it was big enough to take the meta that I was adding.

I changed the Grenades model [Hack #76] to the Assault Bomb and increased the burst to 15 so that the tank would either spray these bouncing bombs over a wide area or like the scorp in a concentrated burst. Then in the [proj] in the Tag Editor, I edited the grenades to bounce further on so that they could be fired into bases and literally around corners to flush out hiding opponents.


Ghosts

Again, as there was no human counterpart to the vehicle, I used their projectile to make a simple swap so that they could be included if people wanted them.

In Undeadlong, I removed Ghosts because some of the projectiles that I injected were using meta tags from them.


Banshee

This was removed as there was no human counterpart to the vehicle and it was too easy to find the hidden super weapons on the levels.


Human Chain Gun Turrets

I just upped their rate of fire and added the same impact effect from the Scorpion machine gun. For balance, the damage was reduced to the same level as the scorp.


Covie Gun Turret

I left the original projectile on the turret and began trying various swaps in the Tag Editor to change its look. The main look of the turret bolt, however, came from the [mgs2] light volume tag.

I added the Spectre's boost light cone to the projectile and increased its speed to match the human turret chain gun projectile. This caused the light it generated to be stretched. This gave the projectile a completely different look. I then swapped in the sounds from the Phantom bolt impact and increased the rate of fire to match that of the human turret.

I wanted to add extra projectiles to the existing list, which was difficult as they simply wouldn't work. However, the existing ones worked, so I used the projectiles that were already there. I had remodeled some of the weapons in a 3D editor but had no way of reinjecting the new models into the game. I had also cut some sound files ready for various aspects of the level like the crusher and some of the guns and vehicles, but there was no way to inject them. However, things are easier now. Tag-editing programs such as Insolence (http://insolence.epgservers.net/index.php) allow you to add whole new tags to the lists.

MrMurder



Halo2 Hacks
Halo 2 Hacks: Tips & Tools for Finishing the Fight
ISBN: 0596100590
EAN: 2147483647
Year: 2004
Pages: 166

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