In the grim darkness of the 22'd century, there is only war. humanity has waged war on itself for decades, turning many areas of the planet into wastelands. With every decade that passes, new weapons are created in order to give one nation an advantage over the other. This arms race has led to the development of the most devastating weapon yet, called the Gundam EVA.

A Gundam EVA is a massive, humanoid-shaped mecha that stands about 30 feet. It is outfitted with many kinds of weapons and covered in the most advanced form of armor. However, underneath the shell is a biological form similar to that of a normal human, but enhanced. These bio-machines contain the same makeup of humans, (organs, bones, etc), and are genetically human. The parts of these creatures are created through advanced bio printers, similar to 3d printers of the last century. After the pieces are formed, they are put together to form the large, human-like figure, and then brought to life. These beings are then piloted by select human pilots, who use them in their massive battles against enemy nations.

Some may wonder why governments choose to build these artificial bio machines instead of going full-mechanized. However, this proves to be a common sense decision, as...........{redacted}............................................

I need to know what kind of materials I can use for these bio-printers to create the skeletal system of these giants. They must be as hard as a normal human skeleton but flexible enough to move around in combat. How can I make this possible?

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    $\begingroup$ You’ll have to rapidly stimulate mitosis with a printer that ejects nutrient, hormones, and proteins which allow an already laid cell to use as a copy. For changing cell types (printing a tendon cell next to a bone cell) you need to print (deposit) a somatic stem cell and induce it with the correct proteins to form the new tissue type. Nerve cells are going to be a problem. They are very large and need to grow with the system. Keeping everything a,ive while printing (with blood) is also a big problem. Tissue in the feet will die before the heart is built. $\endgroup$
    – Vogon Poet
    Commented Oct 28, 2019 at 1:00
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    $\begingroup$ Why is bone not the answer? $\endgroup$
    – John
    Commented Oct 28, 2019 at 1:21
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    $\begingroup$ You've combined Warhammer 40K, the Gundam franchise, and Neon Genesis Evangelion in a single story, and you expect it to be realistic when each separate world runs off a different kind of phlebetinum? Just use Gundanium / AT fields / literally all of Warhammer. $\endgroup$
    – Halfthawed
    Commented Oct 28, 2019 at 18:44
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    $\begingroup$ @john because bone is living cells with a circulation and lymph system. Bone alone does not a skeleton make. $\endgroup$
    – Vogon Poet
    Commented Oct 29, 2019 at 3:51
  • $\begingroup$ Or newtype screwery. $\endgroup$ Commented May 27, 2021 at 14:24

2 Answers 2


I'm afraid not.

I know that you didn't ask a yes or no question, but I'm not sure you understand just how complicated what you're asking for is.

Consider my answer on this question:

Unless the printer is able to completely assemble the atoms before any kind of chemical interaction between atoms occurs... nothing living could be assembled successfully.

And as @VogonPoet has so aptly stated:

Keeping everything alive while printing (with blood) is also a big problem. Tissue in the feet will die before the heart is built.

However, after re-reading the question I noticed that you have also stated the following:

After the pieces are formed, they are put together to form the large, human-like figure, and then brought to life.

So this gives us a bit more to work with. If the creature is 3d printed in a "dead" state:

Still no.

You would need to find a way to completely stop the decomposition of the organic material during the 3d printing process. Otherwise, the creature would likely die soon afterwards.

Additionally, you have the problem addressed in this answer to my question involving giant humans:

Double the size and your human has eight times the weight but only four times the muscle strength and bone thickness to support it. They might be able to move, except that they're only getting half as much oxygen per pound, so they'd be gasping to survive.

Go up to ten times and you die quicker, collapsing and suffocating under your own weight rather quickly.

Even if we were able to somehow decide upon a suitable organic material strong enough to replace normal bone at these sizes, the effects on the lungs and other parts of the body would be tremendous. And if you just handwavium those concerns away, what's the point of trying to make anything scientifically sound in the first place?

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    $\begingroup$ And of course “These bio-machines contain the same makeup of humans, (organs, bones, etc), and are genetically human.” best not get a bruise, or your DNA is going to repair it with something very different. $\endgroup$
    – Vogon Poet
    Commented Oct 29, 2019 at 3:55

If you have the sort of technology needed to create an "Evangelion" from Neon Genesis Evangelion (which is the closest analogue to what you are describing), then biological science will be used to attack the Evangelions with a host of biological weapons, ranging from artificial predatory species, flocks or swarms of small biological units, virii, bacteria and other forms of nastiness.

Given the amount of resources and time scales involved, you might rapidly discover the Evangelion are essentially obsolete from the moment they are decanted from the printer (unlike overlord and some of the other commentators, I would suggest that living organisms might be feasibly "printed" using various techniques, such as immersing the printer in some analogue of blood or amniotic fluid, to creating cartilage "templates" for organs and other parts to deposit stem cells into). However, while the printer is erecting a maze of cartilage "scaffolding" over a titanium skeleton, the opposing nation is doing the same for 3000 small hawk sized artificial units. As the Evangelion is being "built" in its swimming pool sized fluid chamber, the opponent is decanting multiple assembly runs of their units from microwave sized printers, and doing things like adding explosive charges in empty body cavities, filling venom sacks with powerful potions and coating the talons with an amazing variety of bacteria.

So while what is being suggested isn't entirely impossible, it does not represent an efficient use of resources. I'd be far more worried that someone is cranking out a billion dragon fly sized robots or biological units instead....


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