#pseudopupil

[anniemoia]

Chinese Mantis  Tenodera sinensis

[revretch]

Trick or treat! :]

Aw, what a cute picture!! Let's talk about bees, who famously have an eye for art (dance, honeycomb construction).

You know how praying mantises appear to have "pupils"? These are called pseudopupils, and honeybees have them too! However, because honeybee eyes are already pitch black, it took some work on the part of scientists to find it.

Source: https://www.researchgate.net/figure/A-induced-fluorescent-pseudopupil-in-the-dark-pigmented-compound-eye-of-the-honeybee_fig5_355703686

[humansbgone]

How’d you get the pseudopupil to work on Sophodra’s “real” model?

I'm glad you asked! The answer is complicated, and I want to eventually do a post with video explaining how it works. If you want some word vomit explaining it for now, though, keep going below the cut!

For those unaware, pseudopupils are what those pupil-like dots on the eyes of animals like mantises and crabs are. You might be aware that both mantises and crabs have compound eyes--that is, each eye is formed of thousands of little eyes (ommatidia). A real pupil is a hole in your eye that constricts to concentrate the light that hits your retina. A pseudopupil is something entirely different. It works based on the polarization of light--that is, where the compound eyes reflect the light that is aimed directly at you, the ommatidia turn black. As a result, like the Mona Lisa, mantises will always seem to be looking at you.

As you can imagine, this was a pain in the ass to set up on a 3D model. So, I had to get creative.

Basically, in 3D you have what are called "shaders." These are what make all the difference between something having realistic shading, and something having a more cartoony cel shading kind of look (e.g. Shrek vs. Okami).

Setting up the shader for the compound eye itself wasn't a big deal--I had a dot texture, and I made it very reflective with high contrasts for light and shadow. The pseudopupil presented all kinds of problems, though--for one, the problem of wrapping a texture around a sphere (notice the way a globe gets squished on an atlas--the poles are not actually nearly that big relative to the other land masses!). Add to that the fact that a mantis's eyes aren't perfect spheres, and you ended up with an effect where the pseudopupils are warping drastically in size and shape whenever they move around the eye. I painstakingly edited the UVs (that is, the way the texture maps to the grid representing the model's surface), and it still looked wrong. So, using an image texture for the pseudopupil was a no go. (I did eventually figure out some methods that didn't warp across the eye like that, but I ended up not liking them as well as the method below.)

There was also the problem of moving the pupil around the eye to begin with. The obvious method was to make an empty (an invisible object) to tell the texture which coordinates in a 3D space it should move to, parent that to a bone, and then just rotate that bone around the eye. I was using a similar method for the cartoony Sophodra model, and figured that would transfer over. The texture coordinates wouldn't behave right, though--the way they transferred the coordinates from a 3D system to a 2D system was unpredictable at best. (Again, I did eventually figure out a way around this, unrelated to the method I settled on.)

There was also the fact that the texture didn't look right. Light behaves a certain way that even a moving sticker doesn't capture, even if the sticker works right.

And that's when I realized that, like an actual pseudopupil, I should make it respond to light!

So, I went into the shader, and modified it so that the very brightest light, instead of being white, would show up as pitch black! Then, instead of empties, I parented a couple of very tiny, very bright lights to the eyes. I was amazed at how well it worked! I have to be careful with the lighting in the scene, and correct for angles that make the lights start moving off the eyes onto the face, but it gives her that gleam that makes a mantis eye really look like a mantis eye. (You can spot the artifacts of this method in the way there's a glow around the pseudopupil in darker lighting, but I ended up liking that too!)

As for making the pseudopupil follow the viewer, that was easy--Blender (the program I use) has a modifier for making objects rotate to follow another object, so I just rigged the bone up to follow the camera and that was that! (I haven't had a whole lot of opportunity to show that off yet, though--hope to soon!)

Thanks for reading this far! I hope it was interesting :)

[sproutjpg]

archive moodboard for @pseudopupil

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[radio-charlie]

@pseudopupil said: I wanna try one of these so bad but i havent seen one yet. Ive had those spiced tea eggs tho -theyre good

mmmm yes tea eggs are the best midday snack. are you still in thailand? i think they sell century eggs there, but dunno if they’re served just plain with pickled ginger on the side. defo still good and worth a shot tho

[radio-charlie]

@maimakan said: Apa itu gyokuro

gyokuro is a very atas japanese green tea, the plants are grown in the shade i think. the flavor is very sedap, like sencha intensified 2x but toastier and earthier, lingers longer too. u gotta keep the brewing temperature lower than the markings those electric thermos usually provide (if u have one that has a 60 degrees marking then that’s ok) so might have to use thermometer. hojo in the gardens midvalley sells if u want to try :D

@pseudopupil said: Bottle it up n send it here!

Coming right up: one free bottle of gyokuro with $150 shipping fee

[radio-charlie]

@pseudopupil said: *still goes broke there cus im hongrey*

lolol its ok. next time u come round these parts just go to Restoran Rebung Chef Ismail and steadily wreck their buffet for 3 hours 

[aedeagus]

pseudopupil replied to your post “should i post my art fight stuff here again this year?”

yes plz

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consider it done! thanks btw for the interest :)