How do you aim at Icon of Sin?

[kuchitsu]

Never really figured it out. Any good visual clues to use?

[Jaxxoon R]

You don't. You ride the lift and shoot rockets into its brain.

[Deleted_Account]

When you start nearing the top hold down the fire button and listen for the scream, repeat. Use the rocket launcher, of course.

[schwerpunk]

idclip

[Cruduxy Pegg]

Rocket moves up a bit I think so you shoot a little below the IOS weak point (at least this is from memory).

[Spectre01]

Enable free mouse look, turn off autoaim then stand at a reasonably high elevation and pump rockets into the brain.

[fraggle]

You fire the rocket just before the elevator reaches the top. Or you can fire just after you jump from the top of it.

It's a stupid design for a boss.

[printz]

Pegg said:

Rocket moves up a bit I think so you shoot a little below the IOS weak point (at least this is from memory).

Wrong, Doom sadly has no velocity transfer like that. But you do need to mind that there's a big delay between pressing ctrl and the rocket exiting the cannon.

[june gloom]

fraggle said:

It's a stupid design for a boss.

Agreed. To be honest if you're going to basically rip off Contra, do it right.

[Gerardo194]

Piper Maru said:

When you start nearing the top hold down the fire button and listen for the scream, repeat. Use the rocket launcher, of course.

It reminds me when I told the same clue to my teacher heheh. He didn't know how to beat it.

[snapshot]

Easy, ride the lift in the middle of the Map and wait for it till it raises then keep shooting it's brain .

[CreamCheese]

kuchitsu said:

Never really figured it out. Any good visual clues to use?

You exit the game and load a .wad with a good boss like Icarus or CChest3 instead.

[Spectre01]

CreamCheese said:

You exit the game and load a .wad with a good boss like Icarus or CChest3 instead.

Step 1: DL a new wad. Step 2: idclev 30 Step 3: iddqd idclip Step 4: Run forward until you hear the Romero voice. Step 5: Laugh, exit the game and delete the wad.

[durian]

Fire a rocket as the top of the RL passes the bottom of the Icon's chin.

[kuchitsu]

durian said:

Fire a rocket as the top of the RL passes the bottom of the Icon's chin.

Wow thanks, this works wonderfully for me and it's a very clear indicator. Now to learn the timing of shooting when jumping down... This will be much more difficult I guess.

[Doomkid]

Beaten to the punch by durian :) I love the IoS, that timing sorta stuff has always been fun to me, much like the castle levels in older Mario games in a way. I find it funny that some Doomers who are otherwise far better than I am struggle with it!

[scifista42]

The IOS's brain hole is positioned at height 384 map units, and is 32 units high. A flying rocket is 16 units high and is fired from 32 units above the player's feet. It takes 8 tics between pressing fire and your rocket actually being fired. Lift raises 4 map units per tic. So, the very optimum moment at which you need to press fire is when the lift's floor is at height (384 + 32/2 - 16/2 - 32 - 4*8) = 328 map units. And here is a screenshot taken when standing on the lift's floor being at exact height 328 map units. So, you should press fire exactly at the moment when you see exactly this, and you can afford a leeway plus minus 2 tics to still successfully hit the hole.



EDIT: New research: This is actually true only in the newest ZDoom, in other engines the right moment would come 1 tic earlier. See this post below for a more thorough analysis and more correct answer and picture.

[RUSH]

scifista42 said:

and you can afford a leeway plus minus 2 tics to still successfully hit the hole.

Most excellent, thank you good sir. I did not know this. Now I will be the MASTER IOS HOLE PENETRATOR! WOO!!! (Many holes were successfully hit/smashed/destroyed from this day forward)

[Da Werecat]

If you made the lift a static platform to take the screenshot, then it's not exactly the real view from there. When a platform moves, the camera shifts in the opposite direction.

[scifista42]

I have just realized that possibility and made a thread asking how much the shift is and if it's source port dependant.

[Da Werecat]

I wonder if the projectile spawn point shifts too. It's hard to verify without looking at the source.

[edit]

Not that hard with the plasma rifle. Doesn't look like it shifts.

[scifista42]

Based on a reply I've just got from Linguica in the other thread, it seems like not only the player's view, but his entire body's Z position is one tic late behind what it should be according to the lift floor's current height. And this is the part of the source code responsible for setting a fired missile's Z height:

z = source->z + 4*8*FRACUNIT;

Where source is the player. Which should mean that, unless there are yet other factors to consider, my screenshot is actually correct - the player should optimally press fire exactly when seeing what's on the screenshot, because that's when the player's body is at the right height, no matter that the lift's floor is already higher.

EDIT: On the other hand, it may also depend on whether a missile is fired before of after the player body's position is updated. Hard to decide indeed.

EDIT2: Well, no, apparntly it's even more complicated than this.

[scifista42]

As Linguica and Graf Zahl pointed out in the other thread, and if I understood correctly, the sequence of actions within one tic goes as follows: Player's actions are performed first (including taking input, firing a missile, and setting height of the view camera), then actions of the moving lift (which will actually update the player body's Z position but not the camera height), and then the scene gets rendered.

As the lift is moving upwards by 4 units per tic, the camera height at the beginning of each tic will be (41 - 4) units above the player's feet, but the player's feet should be exactly on the lift's floor.

Now let's look at the IOS setup tic after tic:

---

Initial situation before tic #1:
Lift at height 328. Player's body at height 328. Camera at height 365 (that is, as if the player stood still at height 324). The player has just pressed the fire button.

Tic #1:
Player thinker: Rocket launcher's Ready codepointer detects that the fire button is pressed. The rocket launcher begins firing animation at tic 0. Player's view is updated to 328 + 41 = 369.
Lift thinker: Move floor 4 units upwards to 332. Update player's Z position to 332.

Tic #2:
Player thinker: Rocket launcher continues firing animation at tic 1. Player's view is updated to 332 + 41 = 373.
Lift thinker: Move floor 4 units upwards to 336. Update player's Z position to 336.

Tic #3:
Player thinker: Rocket launcher continues firing animation at tic 2. Player's view is updated to 336 + 41 = 377.
Lift thinker: Move floor 4 units upwards to 340. Update player's Z position to 340.

Tic #4:
Player thinker: Rocket launcher continues firing animation at tic 3. Player's view is updated to 340 + 41 = 381.
Lift thinker: Move floor 4 units upwards to 344. Update player's Z position to 344.

Tic #5:
Player thinker: Rocket launcher continues firing animation at tic 4. Player's view is updated to 344 + 41 = 385.
Lift thinker: Move floor 4 units upwards to 348. Update player's Z position to 348.

Tic #6:
Player thinker: Rocket launcher continues firing animation at tic 5. Player's view is updated to 348 + 41 = 389.
Lift thinker: Move floor 4 units upwards to 352. Update player's Z position to 352.

Tic #7:
Player thinker: Rocket launcher continues firing animation at tic 6. Player's view is updated to 352 + 41 = 393.
Lift thinker: Move floor 4 units upwards to 356. Update player's Z position to 356.

Tic #8:
Player thinker: Rocket launcher continues firing animation at tic 7. Player's view is updated to 356 + 41 = 397.
Lift thinker: Move floor 4 units upwards to 360. Update player's Z position to 360.

Tic #9:
Player thinker: Rocket launcher continues firing animation at tic 8. Rocket is spawned at height 360 + 32 = 392, which IS the optimum height. Player's view is updated to 360 + 41 = 401.
Lift thinker: Move floor 4 units upwards to 364. Update player's Z position to 364.

---

Conclusion: The player should press fire immediately after seeing his camera view being at height 365, which is akin to the player standing still at height 324, which is depicted on this screenshot: (4 units below the position on the previous screenshot)
¨



So, the above picture is the actual picture the player should see at the exact moment of pressing fire for an optimally timed shot.

However, Graf Zahl pointed out that the newest ZDoom synchronizes camera view with the player's position, which means that if you're playing in the newest ZDoom, the original picture I posted before shows the optimum moment when to press fire when seeing it.

[kuchitsu]

Oh wait, but what you see also depends on your position on the platform.

[scifista42]

Well, my screenshots were taken while standing a little bit in front of the center of the square platform.

If anybody wanted to find out an optimum picture from a different point of view, all he needs is to make a copy of MAP30 with the platform positioned at height 324 and player start placed at the place which he wanted to check out, and the start view would be the optimum view.

Players during the game can check out their position on the platform by using the automap, and if they memorize the optimum position, as well as the optimum picture to see at the right moment to shoot, and have quick reflexes for timed keypresses and good horizontal aim and no monsters in front of them, it should be able to help them maximize their chance to hit the IOS's brain.

[Lila Feuer]

All of id's bosses are terribly designed. The worst offender being Quake 1's Shub-Niggurath and second worst Doom II's Icon of Sin.

As for the rest? Easily exploitable or easily overpowered (by the player) such as Wolf3D bosses, Cyberdemon and Spider Mastermind, and Q2 bosses.

Actually, I'll re-place my worst ones for 2nd and 3rd places, because fuck Xaero for aimbotting on Hardcore and Nightmare.

[40oz]

durian said:

Fire a rocket as the top of the RL passes the bottom of the Icon's chin.

Whoa, nice! I wonder if there are other icon of sin maps where this trick works.

[scifista42]

Assuming the same speed of the raising lift and the same distance of the platform from the IOS, it will work. Otherwise the perfect place would have to be discovered (either by repeated ingame attempts, or by calculation and examining the map in an editor) from scratch.

[Doomkid]

Cyanosis said:

All of id's bosses are terribly designed. The worst offender being Quake 1's Shub-Niggurath and second worst Doom II's Icon of Sin.

Yeah the Cyberdemon and Mastermind are way better than the IOS, whenever I want to go to sleep those boring ass battles lull me into a restful state instantly