Wednesday, 17 July 2019

Slowing down before speeding up again

I haven't written a post for a long time, and neither have I produced many new paintings for The Book. There are two reasons for that; I will explain both, and will show some sketches of what is going on.

The first reason was that I was facing two complicated concepts. The Book at that point counted over 100 pages, meaning over 50 full paintings, not counting maps, scale drawings and additional smaller illustrations. I had kept the work on hexapods for last. Hexapods largely take the position of terrestrial vertebrates on Earth. They also represent a similar degree of adaptive radiation, so there are burrowing animals, animals analogue to amphibians, predators, brachiators, and much else. Some returned to the sea, and there is at least one group, but probably two, that have learned to fly. I had aimed to devote at least 15 full paintings to hexapods, keeping them for last. I actually have quite a few oil paintings of hexapods that I could simply paint again, now digitally, and most importantly better. But I was no longer satisfied with two important design considerations: their jaws and legs.

Jaws
As for their jaws, until now the idea was that hexapod ancestors had six jaws, placed radially around their mouths, with one row of teeth each. I envisaged that the two upper ones would meet at the end and connect, forming an arc in very much the same way as our mandibles form an arc. The two lower jaws would do the same, resulting in four jaws: both the one at the top and the one at the bottom form arcs, and the lateral ones would bear one row of teeth. This provided much design freedom, so the lateral jaws, or an upper or a lower arc, could grow into ploughs or whatever instrument might be useful.
   But over time I became dissatisfied with this design, as I wanted something that would work but would be stranger than the earlier design that looked too terrestrial. My attention was drawn by 'linkage systems'. These are the complex assemblies of often more than for bones that allow fish' mouth to suddenly telescope outwards to double their length, and do other interesting things. I have used linkage systems before; the rusp snout is a design I like. Now, Earth fish are obviously bilaterally symmetrical, so designing a linkage system for fish more or less involves movement in a vertical plane lying parallel to the longitudinal axis of the body. Thinking of linkage systems in two dimensions is not that hard. You turn them onto a three-dimensional mouth by connecting the frontal ends from the left and right sides.
   Furahan hexapods are also bilaterally symmetrical, but their mouths started out as a radial design (here and here). How about a radial linkage system? Now that is a challenge: do adjacent jaws slide along one another to provide cutting surfaces? Or do they simply point inwards, with pointy teeth on their ends? How do adjacent jaws link up to provide an extended reach and yet allow a forceful bite? This requires some serious though and probably tinkering with diagrams and possibly bits of cardboard or wood; what it takes is time...

Legs
With six legs, may gaits become possible. That is not the problem. But I certainly did not want to fall into the trap that I complained about before (one, two, three and four): many artists having to draw six- or eight-legged animals simply copied the hind legs as often as needed. In many cases those doubled hind legs moved in unison, making the whole assembly superfluous. One way to avoid that would be to come up with a different gait, which is not difficult, as I explained before.
  But there is another problem, and that is the anatomy of these legs. It makes sense to design legs for big animals in such a way that the segments bend in alternate direction: if the topmost one points backwards, then the next one down should point forwards, etc. (see here and here). This results in a zigzagzig pattern, and if the top one points forwards, you get a zagzigzag pattern (see here and here). With two pairs of legs, one can be zigzagzig and the other zagzigzag, or both can be zigzagzig (or zagzigzag). But with three pairs of legs there is a challenge of how to avoid repetition. So I played with joints that point forwards while the leg moves backwards and that still point backwards while the leg moves backwards. I haven't made proper animations yet, but the sketches reveal that the result certainly looks odd. The problem is that the joints would have very large ranges of motion, which cannot be good for stability. At present I think the best solution may be to apply one pattern for all pairs of legs, such as zigzagzig (or zagzigzag). I will need to do some serious animation studies to come up with the best design. Again, that takes time...

The time did not seem to be a big problem; I had already decided to reduce my working hours by about one third to about 36 hours a week, which would free the time to do this, make animations and more besides.

But something came up. I had been living on my own for a long time, being a widower. But I unexpectedly met someone who is now very dear to me; as I am sure most readers will know from experience, time spent on a relationship is not only time spent well, but also spent lovingly. So to my surprise I found my newly liberated time taken up by a very positive development. Where does this leave The Book? Well, the answer is that it will require another realignment of priorities. And the only thing that is a suitable candidate for reduction is work, so there will be less of work and more of other things.

Some appetizers
I was not all lazy meanwhile! I just finished one painting and another one will be finished shortly. The Book will contain at least two examples of the official portraits of dignitaries and luminaries who are honoured by having their portraits in the halls of the Academy and the Gallery of the Institute of Furahan Biology. These people are Grover P. Uytterwaerde, the third Rector Praeses of the Furahan University, and Profissima Tartufa S. Rulyinka. Actually, one of the first posts in this blog already showed a sketch of such a portrait.

Click to enlarge; copyright Gert van Dijk
The other painting shows rusps, this time of the microrusp variety. While I was gathering courage to tackle the hexapod 'jaw and leg' problems, I thought I could fill the time with rusps. In this case, I took the 'flexible evolution of limbs' that is also apparent in another post a bit further. Instead of reducing some limbs at the front of the animal, why not do away with some in the middle? That would provide a supple anatomy. The 3D sketch above was done in ZBrush, done mostly to work out the shape of the head (rusps heads are complex). I did not bother modelling the legs as it is easier to just draw them.

Click to enlarge; copyright Gert van Dijk
Here is a sketch of an entire animal, legs and all. Fully grown ones are about the size of a fox.

Click to enlarge; copyright Gert van Dijk
And this is the beginning of a painting showing these microrusps. The setting is dawn in a dry environment. A group of these animals, called 'baloors', are having their first look at what the day may bring.          

Click to enlarge; copyright Gert van Dijk



No 'Gigafiffyfees'
Here are sketches of a species that will not make it to The Book. I took the Fishes IV design, and thought they might ebolve into giant filter feeders. To that end the upper and lower jaw arcs would envelop the much altered lateral jaws that contain the filtering apparatus. The tips of the upper and lower jaws can be closed to stop filtering and so reduce drag. With the tips open, water would flow through the filter continually, flowing out through outlets at the corners of the upper and lateral jaws. These animals are hexapods, and their hind legs have formed flippers much like whales' tails.


Click to enlarge; copyright Gert van Dijk
I even started a painting of an altered design, in which the lateral jaws envelop the upper and lower ones. As these are 'giant filter feeder fish', they became 'gigafiffyfish'. No, I do not know why; perhaps some zoologist's toddler could not say 'giant filter feeder fish' and the garbled result was adopted as the animals' name. If this is not true, it is still a good story. Anyway, in the end I decided against them: even though they make sense, they are too much like Earth whales.     

So that's why I've not shown much new material. But the outlook for more material is very bright.  

9 comments:

Anonymous said...

The baloors are adorable.

>lazy
you are NOT lazy - you had better IRL things to do. None of us begrudge you happiness, so go for it!

>legs
the forelimbs of Earth came from fishes both pushing themselves along & doing pushups to get air, right? I suppose the question is, what did the early Furaha hexapods use their forelimbs/midlimbs for?
(imho, nothing wrong with having two sets that are structurally forelimbs, give that you're not going to committ the sins of _Avatar_, having them right alongside each other)

-Anthony Docimo

Anonymous said...

hm, had a thought just now: perhaps the earlier, inaccurate leg structures of the oil paintings, are from an artistic school who hold its better to display the might/?/spirit of an animal or plant, rather than have every detail anatomically accurate?
(like how not all paintings of water lilies here on Earth, look very much like water lilies)

-Anthony Docimo

Sigmund Nastrazzurro said...

Anthony: thank you. I haven't actually worked out the 'amphibian'stage of hexapod evolution, although some of the anatomical details of the 'Fishes' group that climbed ashore set the scene. That particular group looked somewhat like plesiosaurs, meaning that a neck was already present before the first one raised its head above the surface of the water. As the aquatic ancestors used their limbs for locomotion, and as their terrestrial progeny diud the same, the ones in between must have done the same. That scenario is uncomfortable similar to the Earth one, but I cannot think of another one that makes an equal amount of sense.

I agree with your statement about early depections of multi-legged animals: for the artists, directors or producers involved the benefits of impressing the audioence with cool looks will far outweigh the importance of scientific accuracy.

That subject was discussed in the blog in the past. It also applies to dinosaurs, where filmmakers prefer to ignore feathers and lips. Did I see your name on Patreon? If so, and if you can access it, there is a nice Powerpoint on that theme by John Conway: https://www.patreon.com/posts/what-went-down-28660923

Anonymous said...

The idea of radial jaws with linkages sounds exactly like the Aristotle's lantern of a sea urchin. There are even artificial models pretty close to what you described already viewable on YouTube.

Sigmund Nastrazzurro said...

Anonymous: Thank you fo the siggestion. I hadn't gotten as far as sea urchins yet! These lanterns are a good inspiration. It looks like I will hev to delve deep into the source matetrial to get a close look at the precise mechanics. At my present stage of thinking, I wam considering mechanims that shoot out to catch prey as wel as teethe that slide along one another. The lantern looks like they are useful for the second concept, but not much for the first. But I would like to see the mechanical details first.

Anonymous said...

hmm...well, both "elbows" and "knees" (splayed and under the body) can be used to propell the body around; Earth early tetrapods lacked a neck, so the push-up stage is not something Furaha's early hexapods would *need* to do (though they might do push-ups for another reason (courtship? intimidation?)

thanks for the link; yes, I'm still on Patreon. If I may ask, have you looked at In Defense Of Plants, either on Patreon or online? http://www.indefenseofplants.com/ lots of fascinating strategies used by plants - flowering, gnetophytes(sp), parasitic, and more. (one flower actually grows a pole for birds to perch on)

have nice days and be well.

-Anthony Docimo.

Sigmund Nastrazzurro said...

Anthony: our messages seemed to be going in different directions, so I think I misunderstood your original question. Sorry about that. I will think about it some more as I haven't given the transition to land much thought. Many tropical fish that gulp air have a mouth that opens to the highest point of their body, so gulping air can be done simpler than with redeveloping fins. But suppose the mouth may not be altered for some reason, then high fins will do the trick of getting you a mouthful of air from the water. But some other advantage must have become available once they got to that stage, or why would else they evolve further? I will try to read up on that putative second advantage. Fresh greens? Fewer predators?

Spugpow said...

Congratulations on the positive developments in your life!

Anonymous said...

Rodlox here.
Had a better thought than what I'd thought earlier: leave the initial amphibious tetrapods' conquest of land a mystery - Romer's Gap on another world, and let any modern amphibious forms and "amphibians" be later arrivals from land-lubbers and other marine lineages.

That way, you can focus on how you want the hexapods' limb layouts to be, rather than to be stuck on the conquest of land for who knows how long.

just a thought.