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Squid Simulations and Further VFX Tricks

Biology of a Squid

Squids are cephalopods. They have elongated bodies, large eyes, eight arms and two tentacles. They have distinct head shapes, and symmetry that helps with their aerodynamics through the water. They are soft bodied like octopuses, but unlike octopuses they have a small skeleton. Their skeletons are very “pen-like” in shape and are made of chitin.

Squids are very ancient creatures. They branched off from other types of cephalopods during the Jurassic period. Crown coleoids (the ancestors of octopuses and squid) diverged at the end of the Paleozoic period. The ancestral coleoid to squids is hypothesized to have a shell unlike its currently alive counterparts.

Unlike the octopus, these creatures grab food with their two tentacles and use the rest of their limbs to restrain the prey. Overall, they have around 10 limbs. On most of their limbs they have multiple suction cups and horned rings. Similarly to the octopus , they use their beak to cut up their food into chunks. Some types of squid also hunt cooperatively instead of hunting alone.

Squids are very efficient swimmers. They move through jet propulsion and have very efficient eyesight. However, they are color blind. They are equally as smart as octopuses. Squids are preyed upon by sharks, other fish, birds, seals, and whales.

Squids can change color. They mainly use this as a defense mechanism and for camouflage. They also use it for communicating with other squid and fish. Some squids are even bioluminescent. Luminescent squids have several light organs that they use to light themselves out.

Squids also eject clouds of ink to distract them from predators and escape from them. The only predator it doesn’t work on is humans. Which is why they never escape from becoming calamari.

Some types of squids are very misleading with their name. The vampire squid for example is more related to octopuses than it is to squids. But cuttlefish for example are considered a type of squid.

There is very little known about the life cycle of a squid. Some squids lay eggs and attach them to floating weeds. While others use the bottom of the ocean floor. Some hatchlings resemble squids as soon as they are born, while others have a planktonic larval stage.

The smallest squid in the world is the Southern Pygmy Squid. The males only grow to about 1.6cm in length. The largest squids are the Giant and Colossal Squids. They are also the largest living invertebrates. The largest giant squids that have been recovered were almost 13 meters in length.

Giant squids have several interesting attributes.

Their eight arms have on average 2 inch wide suckers that are toothed. Their mouths also contain something called a radula. A radula is a tongue-like organ that is covered in rows of teeth. This tongue is located inside the squid’s beak.

Their heads also have eyes that are the size of your average dinner plate. Which are usually around 30 centimeters wide. Their eyes have the largest head to eyes ratio in the animal kingdom. Because of the massive diameter of their eyes, this allows them to see very tiny creatures, and bioluminescent prey.

Just like regular squids their brains are shaped a bit differently than ours. Their brain is shaped like a donut and is fitted around their esophagus.

There is some debate in the science community if giant squids are their unique species, or there are other subspecies of giant squid. There is evidence to suggest there are as many as 8 different species. However, giant squids are hard to track because of their preference to live at very deep parts of the ocean.

The first ever giant squid caught on camera was in 2006. Scientists from Japan's National Science Museum and a team at Discovery Channel teamed up and recorded the squid live.

There are an estimated 500 species of squid that exist in the ocean. Most species are only about an inch long.

Squids are closely related to snails. clams ,and slugs as they are all mollusks.

Scientific Simulations and Visualization

There are many scientific students about squid. We have a lot to learn from them as they can exist in depths of the ocean that are unseen to us.

So of course one particular interesting thing we are studying of squids is their ability to communicate in the dark. Squids at the deepest depths of the ocean are bioluminescent, and emit their own light.

Researchers at Stanford University and the Monterey Bay Aquarium Research Institute (MBARI) suggest that the reason that deep sea squids emit light is for visual communication.They liken the glowing lights to illuminated words on an e-book reader. The squid’s light producing muscles create backlights for the squids color changing skin.It is then suggested that squids use these light and color changing patterns to signal each other.

Squid behavior is almost impossible to study as their behavior changes when they are in captivity. So most observations of their behavior happens in the wild and with ROVs. However, with ROVs , scientists are able to observe the squids' eating behaviors and how they behave in packs. They found enough evidence to suggest that the squid's skin patterns relate to specific situations. Some patterns they observed suggested the animals were communicating precise messages to each other. Deep sea squid do not have great vision, so it is also suggested that their light producing organs help boost their visual communication abilities.

Most of these animals' light producing organs are located between their eyes and the edges of their fins.

Scientists are also studying squid brains as well. So far, they have been able to complete the first MRI map of one.

Wen-Sung Chung of the Queensland Brain Institute and his team are looking into the neural ability of the creatures and how their brain controls their camouflage abilities.They found that squid brains are more complex that rats or mice. They estimated that squid have the intelligence of an average dog.

Squids are subconsciously aware of how their skin works and can communicate complex phrases to other squids.

These scientists found out that some cephalopods have more than 500 million neurons. In comparison, rats have about 200 million.

There are certain characteristics from these creatures that scientists are trying to replicate in Humans. They recently were able to engineer human cells with squid-like transparency. Researchers at the University of California, have been studying the color changing effects of squid skin, and how it can be replicated. As well as how color changing cells could benefit human technology. Specifically,in developments of infrared camouflage and other advanced materials.

Squids such as the females in the species of Doryteuthis opalescens, evade predators by creating striped patterns across their bodies. So finding the engineering equivalent of this effect could help humans immensely.

The researchers were able to borrow some of the intracellular proteins in the creature's skin, and found a way to introduce them into human cells. They also found that this effect is transferable in many different animals.

Squids have special reflective cells called leucophores which can alter the scattering of light across their bodies. Inside of these cells are leucosomes,which are membrane-bound particles. These membrane particles are made up of proteins called reflectins. This produces the squids' camouflage abilities.
After isolating this protein, scientists were able to culture human embryonic kidney cells and genetically engineered them to contain reflectin. They then observed the new cells and watched them distribute reflectin throughout other cells.

There are also 3D simulations scientists are making of squids. Part of what scientists are simulating right now are squid’s giant axon. The axon is the part of the squid that controls jet propulsion. On average, it is around 1.5 mm in diameter. It was first discovered in 1909, but the discovery was ignored until the 1930s. The axon allows the squid to make very fast rapid movements through the water.

The applications of this study are not just limited to propulsion technology for humans. It is also applicable for developing electrically driven implants in humans. Neurons play a key role in the basics of medical research and making these implants work. The more neurons and the faster they simulate a cell, the faster an organ or device works.

Using Fitzhugh-Nagumo equations, they were able to model spike generation and propagation models for squid axons. While also using CFD. While building these models they particularly studied flying squids.(Sthenoteuthis oualaniensis (S. oualaniensis)) These are squids that leap out of the water and into the air.

By studying these squids they were able to generate flow fields of the squids “launching phase”, and the parameters the squid needs to launch itself through the air. They discovered that the creatures create a trailing jet and vortex rings to generate thrust. Their jet strategy is to produce greater time-averaged thrust, and lacks propulsion efficiency. Hence why the squids don’t stay in the air too long, or are thrusted very high.

They also found that if the squids could launch themselves at a lower angle than they currently do through the water, they could escape predators faster, and could create a larger flying speed.

Squids can also benefit humans in other ways. There is evidence to suggest that melanin in their ink can protect against Escherichia coli (E.Coli), and Listeria monocytogenes (Bacteria that causes Listeria).

The ink contains bioactive compounds that can be used as antibacterial agents. E.Coli and Listeria are bacteria that can cause food damage and disease in humans, so finding a synthetic antibacterial agent could help prevent deaths and reduce symptoms for both.

The one big factor that prevents us from commonly using the melanin from squid ink, is the fact that the ink is very hard to harvest. So developments of a synthetic version are in progress.

Building Squids in Houdini and in Visual Effects

There aren’t many great references or examples of squids in media or film. Which is a shame. I’d argue a lot of the alien creatures we see in films are inspired by squids, and it's a shame we don’t study them more.

Regardless, this is what I could dig up.

Tutorial wise, there are some great ones out there:

Learn Houdini: Howdini101 - 022 - Squid Base:

Learn Houdini: Howdini101 - 023 - Squid Tentacles 01:

Learn Houdini: Howdini101 - 027 - Squid Tentacles 05:

Learn Houdini: Howdini101 - 030 - Mr. Squid Basemesh 02:

So while writing this, I was giving up hope of finding anything particularly Houdini related. However, I found a file and a houdini forum that was fascinating. I will confirm I’ll be testing this file on squids in the future , because it's beautiful.

A user named Anam Hasan, (user name 212A on the Houdini forum) created some simulated squid skin. You can find the forum here:

By using a combination of VOPs, and solvers, he was able to drive the color and scale of fluorescent dots across a surface. Now the build is not scientifically accurate, but it's the closest example I’ve seen so far. The final results can be animated to follow objects, or static ones.

Cinema wise, there is an excellent breakdown on the Before and Afters blog of the squid shower from Watchmen. Find the article here:

There was quite a huge amount of research the team did to develop these squids. Making the squid's skin look translucent and realistic was a huge challenge.The Hybrid FX team was able to build multiple layers of geometry in the squids to create better refractions of light, and to define internal organs.

They knew that this process would also lead to long render times, so they developed tools to isolate their many pieces of geometry better when it came to rendering. They also experimented with the Finite Element Method solver and Houdini’s Vellum solver to create realistic squid movements. But then they used a custom RBD simulation because it worked faster, and looked better. Then to maintain the realistic squish and bounce of a real squid, they added their own custom deformer to keep those characteristics.

Life of Pi breakdowns probably contain some of the best concept art I’ve seen in a while of squids. They have some unique studies of the chromatic changes that are needed when considering the bioluminescence of squids. As well as several other underwater creatures.
You can check it out here:


Scientists engineer human cells with squid-like transparency:

How squid communicate in the dark:

Life history traits of the temperate mini-maximalist Idiosepius notoides, (Cephalopoda: Sepioidea):

BBC Radio 4: Natural Histories - Giant Squid:

Growth of long-finned squid, Loligo pealei, in the northwest Atlantic:

The potential impacts of climate change on inshore squid: biology, ecology and fisheries:

Multiple sensory modalities used by squid in successful predator evasion throughout ontogeny:

Bioluminescent backlighting illuminates the complex visual signals of a social squid in the deep sea:

Raw: Giant Squid Makes Rare Appearance in Bay:

Giant Squid Spotted in US Waters:

Giant Squid:

Giant Squid Caught on Tape for First Time for Discovery Channel's 'Monster Squid:

Giant squid: from the deep sea to display | Natural History Museum:

The Amazing Squid | Nat Geo Live:

The Fierce Humboldt Squid | KQED QUEST:

Vampire squid: neither squid nor octopus | Oceana:

Vampire Squid from Hell - Deepsea Oddities:

What is a Cephalopod? | Oceana:

The curious eyes of the cockeyed squid:

2 Hours Of Squid To Relax/Study/Work To:

Squid: The Deep Sea Devils | Deep Sea Killers:

Giant Squid Attacks Surfboard!:

Learn Houdini: Howdini101 - 022 - Squid Base:

Learn Houdini: Howdini101 - 023 - Squid Tentacles 01:

Learn Houdini: Howdini101 - 027 - Squid Tentacles 05:

Learn Houdini: Howdini101 - 030 - Mr. Squid Basemesh 02:

Squid Skin:

How to simulate a squid shower:

Life of PI:

ILM - Animating Davy Jones and Crew for Pirates 3:

The best of Davy Jones (HD):




Colossal Squid:

Are squids as smart as dogs?:

Humboldt Squid:

3D-Simulation of Action Potential Propagation in a Squid Giant Axon:

Locomotor transition: how squid jet from water to air:

Genomic and Transcriptomic Analyses of Bioluminescence Genes in the Enope Squid Watasenia scintillans:

The Effectiveness of Melanin from Squid Ink (Loligo sp.) as Antibacterial Agent Against Escherichia coli and Listeria monocytogenes:

A system dynamic of the harvesting strategies to sustain the population of squid using logistic growth model:

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