3 category spam, most commonly appreviated as "3catspam" is a technique used by many that involves quick switching and firing three weapons to deal damage easily. To do this mechanic, you will need fast reflexes and good aim, the technique is easier if you rebind your keys. (keep in mind pg3d doesnt have its own rebinding system.)

The most used type of loadout is a left to right 3catspam loadout, which means you equip your weapons from right to left. (for example: secondary to sniper to heavy)

The main thing you need to keep in mind is the weapons delay mechanics. There are three types of delays: Input delay, Output delay, and fixed delay. These delays determine if there is a pullout animation which prevents the weapon from quickswitching.

If a weapon has fixed delay, then it cannot be used in 3catspam as you can't quickswitch with it. If it doesn't you will want to find the right combination of weapons so that no weapon has delay upon switching from another weapon, to find this you will need to know how input and output delays work.

Input delay means a weapon gets a pullout animation when you quickswitch from a weapon with output delay. Output delay means it will give the next weapon you switch to a pullout animation if it has input delay. It is reccomended you have atleast one weapon without input or output delay in your loadout.

You can find delays of weapons on the official fandom wiki: https://pixelgun.fandom.com

The loadout in the image starts off with a backup weapon with only input delay, since it doesnt have output delay the next sniper weapon doesnt recieve any delay, and since the heavy weapon doesnt have recieve or give any delays, it doesnt get a pullout animation or give the backup weapon a pullout animation.

The types of weapons normally used are weapons that can deal good damage in one shot (not automatic weapons like miniguns!!).

For example, the backups known as the laser cycler and the exterminator are good weapons for 3catspam because of their high damaging shots.

You can also use a primary shotgun if you are close range. I'd reccomend acid shotgun or viking, you can also use ultimatum but like 99.999% of players dont own that weapon.

Using a sniper weapon in your loadout is highly reccomended because almost all of them have high damage shots like the harsh punisher, brutal headhunter or digital sunrise.

Special weapons are pretty similiar to backups, pick a single shot weapon with good damage such as reflector, you can also opt for poison darts but you have to note it has shooting delay (not pullout animation)

Heavy weapons are almost always single shot and dont have any delays, so id reccomend including one in your loadout to make it easier.

For movement you will want to equip a high mobility melee (85 or more mobility) such as double cashback, chainsaw or heroic epee.

3catspamming will require some practice to do consistently, but heres the basics:

Equip your first weapon and fire it, then, switch to your second weapon and fire that one, and switch to your third weapon and fire it, after that switch back to your first weapon and repeat the cycle all over again.
It's so simple yet quite difficult that i can't explain it that much without sounding like a yapper.

Have your melee weapon out when you are not shooting so you can move faster.

If you need to reload, find a safe spot and reload your weapons, it is reccomended to have a good weapon that you arent spamming with as an emergency if you need to defend yourself.

BTW, i would reccomend using this strat on small and enclosed maps like classic pool and silent school.

Since i know lots of you are nooby PC players who complain about the game (dont worry i am too), heres how to counter 3catspamming.

Because you cant ADS while 3catspamming, you can use a sniper at long range and outrange your opponent, would reccomend high damage and high zoom snipers like harsh punisher for this.

You can also choose to hinder a spammers movement abilities with weapons like the bubble gum 01 and other slowdown / jump disabling weapons.
If you can't make their movement worse, use aoe weapons to hit them without needing to aim very precisely.

Stealth bracelet gadget is also a good counter as most people will focus on the actual spamming more than the enemies around them, use this to ambush and avoid the 3catspammer from spotting you.

You can also use the reflector gadget and make the enemy take 50% of the damage they would hit you for, making them take loads of damage.

Melee switching is a very difficult technique that involves letting your melee pull out to avoid delays.
here's how to do it:

1. get a melee, preferably with high movement speed (fixed delay melees dont work btw)
2. fire your first gun
3. switch to your melee
4. fire your second gun
5. switch to your melee
6. fire your third gun
7. switch to melee
8. repeat steps 2 to 7

if you do this correctly, you should be able to avoid delays on weapons, so you can now switch from a weapon that gives delay to another weapon that recieves it without getting any delay at all.