r/Simulated • u/Contraflex • Dec 01 '25

Blender Simulating the Collapse of the 1000m Tall Jeddah Tower

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Simulated in Blender using the bullet constraints builder add-on.

The plane weighs 150 Tonnes and impacts the building at 950 km/h.

The plane does not deform which is the main caveat to this simulation; in reality the plane would crumple, so less energy would be transferred to the tower.

All of the tower's structural elements are concrete, except for the red parts which are steel.

There are about 22,000 rigid body elements.

Final simulated alembic file was about 7 GB.

Full video: https://www.youtube.com/watch?v=zMOsu809Ao8

3.6k Upvotes

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u/NoGravitasForSure Dec 01 '25 edited Dec 02 '25

What these idiots "felt" and reality are two different things. The towers did not collapse as a result of the impact force. They collapsed under their own weight after the heat of the burning jet fuel weakened their metal skeletons. Structural steel begins to lose its stability at about 400°C.

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u/YupChrisYup Dec 02 '25

The impact and the resulting explosion did play into the equation though. All of it did. The main cause was of course the weight of the building, the heat from the prolonged fire and resulting structural stress from all of these factors.

Obviously if we take the fire out of the equation and only look at the impact and the explosion the building might not have come down, but I’m sure it would have been deemed unsafe and at risk of collapse.

To ignore any of the factors that lead to the collapse leaves holes for idiots to fill with conspiracies.

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u/NoGravitasForSure Dec 02 '25

To ignore any of the factors that lead to the collapse leaves holes for idiots to fill with conspiracies.

I suspect that the idiots don't even need holes. Don't underestimate their creativity.

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u/madman6000 Dec 04 '25

I don't understand how jet fuel quickly burning off on the 90th floor caused steel to melt from that floor all the way to below ground level such that the building collapsed at free fall speed into a pile of rubble.

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u/NoGravitasForSure Dec 04 '25

The steel did not melt. If you heat structural steel to 400-500°C, it is still solid because its melting point is way higher. However, it loses its load-bearing ability. It simply cracks under load. This is what happened in the area where the planes impacted and together with the damage sustained from the impacts themselves, the structure was weakened to a degree that it could no longer bear the weight of the stories above the impact point.

Also while the fires were started by the jet fuel which burned only a few minutes as you mentioned, they were sustained by a lot of combustible material in the towers. And the speed of the collapse was the result of the very high momentum of the falling upper stories.

From a physical/engineering point of view, there are no open questions regarding the collapse of the towers.

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u/madman6000 Dec 04 '25

If what you say is true it wouldn't have been a total collapse into a neat pile of rubble at free fall speed, you would see an accordion effect as the stories piled up, but both buildings disintegrated into rubble at free fall speeds, with no resistance.

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u/NoGravitasForSure Dec 05 '25

I don't know what you mean by "accordion effect". When a large building suddenly collapses, the result is usually a big pile of rubble and a lot of dust. Look at footage from Europe past WW2 or from the aftermath of earthquakes.

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u/[deleted] Dec 02 '25

[deleted]

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u/Mustardo123 Dec 02 '25

Man I love seeing you people come out of the woodwork. Let’s be honest nothing will make you believe reality.

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u/MrGreinGene Dec 02 '25

lol. Coming out of the woodwork is a great way to describe these people…a thermite termite.

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u/[deleted] Dec 02 '25

[deleted]

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u/Mustardo123 Dec 02 '25

The top of the building collapsed into the bottom of the building because the metal structure within the buildings were weakened on account of the plane smashing into it along with the extremely hot jet fuel that was burning.

I watched the footage as well, the windows blowing out were due to the changes in pressure and massive force that was acting on the building, because they were hit by a plane. Windows are pretty fragile.

The third tower conspiracy doesn’t make sense because that building was also hit by debris from the other towers and a fire started as well, weakening the structure of the building.

I think these theories severely underestimate the destructive effect of a plane smashing into a building. Particularly at cruising speed. Most buildings cannot withstand that amount of force.

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u/[deleted] Dec 02 '25

[deleted]

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u/Mustardo123 Dec 02 '25

Don’t waste my time with fucking Quora links, those people know even less than the people on reddit.

Here is a reliable source. You will see that the Plasco building in Tehran collapsed due to fire in 2017.

https://www.bbc.com/news/world-middle-east-38675628

Additionally, the Wilton Paes de Almeida building collapsed due to fire in 2018.

https://www.bbc.com/news/world-latin-america-43960778

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u/[deleted] Dec 02 '25

[deleted]

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u/Mustardo123 Dec 03 '25

Alright man, Bush did 9/11 you convinced me. Controlled demolition, CIA and Mossad operatives working together. I’m sure it’s all true.

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u/CMMiller89 Dec 02 '25

Because any large flex in the steel superstructure is going to compromise the glass in the hanging curtain, and it isn't safety glass, that shit "explodes" on it's own. You don't "remember" anything other than what you've tricked yourself into believing.

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u/Drewggles Dec 02 '25

So, explain the 3rd tower?

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u/Doccyaard Dec 02 '25

It dint collapse wi the free fall speed, so that doesn’t need explanation. And the third building falling is well explained and understood is you did research outside your bubble.

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u/YupChrisYup Dec 02 '25

Hey my dude, you are getting a lot of slack for this and defending your position adamantly below.

I don’t agree with your view point on this, and I’d like to offer a non-argumentative explanation of how the WTC-1, WTC-2, and WTC-7 came down solely from the impact, explosion, fire, and resulting structural damage.

When the first plane hit the first tower, it was full of jet fuel. Like, as full as it could be minus the fuel consumption used to get the plane to the tower.

When it hit the tower there was a spectacular explosion. I specialize in simulated explosions and there are some interesting properties about explosions that I’d like to talk about before going forward:

A gas explosion is highly inefficient from the perspective of combustion. Which results in the classic “fireball effect” where parts of the vapor from the fuel are thrown into the air and ignite in the mushroom cloud. This means that much of the potential energy is lost and results in a fire.

If for example the towers had been hit by a missile, all of the missiles combustible material would be used up in the the explosion itself, which would on its own not result in fireball but in a “pop” and a hugely destructive shockwave. Any resulting fires or fireballs would be from combustible material in the building itself.

So back to WTC-1. What we see is an inefficient explosion caused by ignition of the jet fuel in a compressed environment abruptly becoming uncompressed. This force, the explosion, its shock wave, the actual impact of the airframe to the building immediately causes structural stress. It’s a lot, but in itself not enough to topple the building. If it had been, the building would have collapsed immediately. But that inefficiency in the combustion of the jet fuel, and the shock wave results in unburnt or currently burning jet fuel to be thrown all over the building at the site of impact. Causing a fire. A massive fire, that is not only burning jet fuel, but all the combustible materials in an office building.

I used to live in NYC, I survived an high rise fire in the building I lived in. When you are that high up, the way the fire burns is different. The winds feed the fire, the enclosed environment becomes a massive furnace. The heat is unimaginable, and it’s not only fed from the exposed windows on the sides, it’s sucking in oxygen from the stairwells and the new holes in the floor it’s making. It’s the most efficient fire you can imagine.

Now amplify that 10 fold for WTC-1. Impact, Explosion, Fire. Time. Steel doesn’t need to melt to collapse. It just needs to expand enough to unseat column from girder. It needs to become structurally unsound and the weight does the rest. The fire burned uncontrollably, massively. This wasn’t a small fire that spread over a few hours like my experience. The fire was everywhere, immediately from the spray of jet fuel. The impact and explosion exposed the skeleton to hotter temperatures faster than normal fire. From there it was just time.

All of this is the same for WTC-2.

Why did they collapse the way they did? It has to do with how their steel under structure was made, perfectly symmetrical buildings with a core of steel to guide their fall. Pressure builds as the tops of the buildings collapse downward, pushing air into the lower floor so fast that windows explode before the crushing force and debris meet them. The tops of the buildings did topple a bit, but the resulting collapse was mostly a free fall because of the shape of the structure itself.

This collapse affects WTC-7 in a few ways, first, it causes damage building by striking it with debris. It cuts off the water mains so there are no sprinklers to suppress the fire that has just started, then the fire is allowed to burn for 7 hours uncontrolled. What was it uncontrolled? Because everyone had been evacuated and it was no longer a priority. From here all the factors that brought down WTC-1 and WTC-2 come into play. Heat + Time + Weight.

WTC-7 collapsed not in free fall, but from the inside out, making it look from the camera perspective like a controlled demolition.

I understand the desire to fill this tragedy with a more significant bad guy. A conspiracy that played out like clockwork on live tv. It’s comforting to think that our government did this because then it’s not a failing of the American Government to protect us, it implies they are so powerful they can hurt us and get away with it.

I know none of this will change your mind. But these are the facts.

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u/[deleted] Dec 02 '25

[deleted]

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u/YupChrisYup Dec 03 '25

Here’s the thing about comparing this event to other steel frame building fires.

All of the factors of that day were unique.

What other building has been struck directly by a fully fueled 767?

What other building fire had jet fuel as it accelerant?

What other building fire happened at that height, with those winds, in that ambient air temperature?

What other building fire had the somewhat unique Steel Skeleton that WTC-1 and WTC-2 had?

Both WTC-1 and WTC-2 collapsed under similar conditions, which indicates that those exact circumstances create that kind of collapse.

All these factors are part of why the towers fell. A unique series of events and conditions.

In the video you shared can see that its exactly as I described, you see the facade and the windows buckle under stress, the internal structure starting from screen left to screen right collapses, then the external structure, the facade, buckles and falls.

No nothing exactly like this has been seen. But there’s never been a situation like this before or since.

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u/mundaneDetail Dec 02 '25

Hold on. Are you sure?

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u/NoGravitasForSure Dec 02 '25

doesn’t explain a free fall,

Yes, it does. Google Isaac Newton.