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QUOTE (Disgustedorite @ Jan 30 2023, 03:51 AM)

Like, I am not saying the joints can't move at all. What you depicted is just very extreme and I'm having a hard time seeing how it's happening with the muscles set up the way they are without also making it impossible for them to stand and hop the way they are also described.

The ankle rotation is slightly less than 70 degrees. Place the elbow on your desk, look at your hand, now look at the back of your hand, your wrist has just rotated it more then 2.5 times the rotation of the visorbill's ankle. Your own ankles do that when doing the 'happy feet' dance move and your legs don't fly.

If its really done for accuracy, I do not think you have fully thought through the level of handicap you'd have to place on your species and the required level of revision you'd have do if you would seriously take this restriction as cannon for biat muscles. Not to mention the lack of good reason to do so in the first place, why would biats evolve to move so robotically? How did they evolve to fly with it? You are drastically sabotaging the plausibility of your own past submissions through a retcon that seemingly has no good reason to be there.

If its done for other reasons, I'm honestly fine with adding "despite angular momentum they cannot outpace ophreys due to Newton's 42nd law stating that a body in motion cannot exceed the velocity of forum politics" into the description. I do enjoy a good lampshade. Would that be satisfactory?

This post has been edited by Jarlaxle: Jan 29 2023, 08:49 PM

I don't think the snark regarding newton is really necessary...

It just seems to me that there's been two walls to get butted into here, the joint being the one here and now.

I think the muscles in the human hand that allow the finger to not only move in a circular fashion but also twist slightly when moving side to side on their base joint is a good body part to observe when considering how this lineage may steer away from the planar motion that seems so conserved in sauceback elaborations.

This post has been edited by colddigger: Jan 29 2023, 09:20 PM

Could you label which parts are which in your animation? Because clearly we have to be looking at different things for that to be moving like a wrist or ankle and not twisting like a disc joint.

QUOTE (Disgustedorite @ Jan 30 2023, 05:41 AM)

Could you label which parts are which in your animation? Because clearly we have to be looking at different things for that to be moving like a wrist or ankle and not twisting like a disc joint.

The color code is the same as listed in the diagram

QUOTE (colddigger @ Jan 30 2023, 05:07 AM)

It just seems to me that there's been two walls to get butted into here, the joint being the one here and now.

Maybe, or maybe not... it might be the confusion between the two issues causing a legitimate miscommunication.

The first question is what muscles are powering the motion, so going step by step:
The muscles at the base of the femur (the hip) provide the main force of the motion. The grashof muscle loop restricts that force into a circular motion and prevents it from breaking away at high acceleration, though the muscles at the base of the tibiotarsus (the knee) are needed to direct the motion into a full circular motion during the initial acceleration, resulting in the circular motion at the end of the tibiotarsus (The ankle).
So far the motion is happening entirely within a single plane, and the translation between the force provided by the femur and the acceleration of the circular motion at the base of the ankle is entirely mechanical.
Now we need physics: As the ankle speeds up, the kinetic energy trying to escape is pushing outwards towards the edge of the circle. Restricted from escaping by the limits imposed by the grashof loop, the energy continues the spin, pulling the tibiotarsus along with it, and the femur in turn. This allows the system to conserve most of its momentum and frees the femur muscles to focus on building up additional angular momentum, introducing additional energy into the system to accelerate it further (though still compensating for losses resulting from friction).
At this point, we break away from the 2D plane: Angular momentum is calculated as P*R, where P is the momentum and R is the radius. As we go further along the wing, the radius - the distance from the center of rotation - increases, while the momentum is maintained. This means that the further out you go while rotating at the same speed, the bigger the outward force becomes. In 3D, we can see this along the wing: As you go further out along the wing away from the body, the further out it can go and the larger the force pulling it away from the center of the circle. As a result, the circular motion at the base of the wing (the ankle) causes the circular flapping motion all the way down to the tip of the wing.

It's worth noting that so far, not a single calory has been used by the ankle muscles or any muscle past the knee. Sadly for our hypothetical ragdoll visorbill, the reality is not an abstract physics model, so IRL we'd need all the joint muscles attachments in place to be able to fine-tune and adapt to the situation, which leads us to the second question: Range of motion.
As the hip & knee motion is standard for any sauceback, so I think we can skip those and move to the ankle. Even within the CAD animation, the ankle's range of motion is almost 70 degrees, because my humor is 12. IRL, that wouldn't be entirely on the ankle, but also include the rotation of the tibiotarsus along its axis, not unlike what happens when we rotate our wrists or ankles, so even if you could argue that the ankle couldn't twist above 45 degrees (which is probably about what is needed for the ophrey at a minimum), the rotation of the tibiotarsus should provide plenty of room to compensate. the next 2 joints after the cannon are the toe joints, which I've restricted to 30 degrees in the CAD as it's showing a basic flapping pattern, though IRL would probably likewise need around 45 degrees to be able to properly maneuver.

This post has been edited by Jarlaxle: Jan 30 2023, 01:47 AM

So it's flicking its ankle around to flap its wings?

QUOTE (Disgustedorite @ Jan 30 2023, 09:42 AM)

So it's flicking its ankle around to flap its wings?

I want to say yes because it's a funny and still viable way to put it, and because I'm tired, but I'm also apprehensive about agreeing in case I'm misinterpreting what you mean by that.

I have a hard time imagining the indirect up and down motion created from flicking it being as strong as just using the chest muscles to move the entire wing directly, like actual swifts and hobbies and hummingbirds and literally every other bird do. Theoretical speed without strength behind it to actually get through wind resistance will not get it off the ground.

I'm not sure what you are thinking of when you differentiate "theoretical speed vs strength", the force of impact against the air is the mass of the wing * acceleration regardless if you generate the acceleration through the biomechanical translation of muscles or steam or shoot a catapult at the end of a Rube Goldberg machine.

Let me put this a different way.

Picture you are wearing a pair of big costume wings that go on your arms like sleeves. Using the full strength of your arms, you can easily flap them and produce a decent gust of wind.

Now imagine if instead of having the wings as sleeves, you are holding onto a handle at the base of them with your hands. You have a secure grip, and a rope or a rubber band is binding your elbows to your waist and preventing you from fully extending your arms. What do you think will happen when you try to flap the costume wings now? Hell, even without your elbows bound.

QUOTE (Disgustedorite @ Jan 30 2023, 11:03 AM)

Let me put this a different way. Picture you are wearing a pair of big costume wings that go on your arms like sleeves. Using the full strength of your arms, you can easily flap them and produce a decent gust of wind. Now imagine if instead of having the wings as sleeves, you are holding onto a handle at the base of them with your hands. You have a secure grip, and a rope or a rubber band is binding your elbows to your waist and preventing you from fully extending your arms. What do you think will happen when you try to flap the costume wings now? Hell, even without your elbows bound.

I'm sure you didn't intend too but you are basically describing the old bike plane prototypes from the turn of the century. Which while not quite good enough to compete with a propeller (which is also "flicked"), did do a much better job getting people off the ground than anyone trying to flap their arms.

The fact you've added "even without your elbows bound" without showing a sign of understanding how critical that difference would be concern me, and make me suspect that again my explanations have gone on deaf ears. Its like you are actively investing energy to resist learning at all cost, or holding onto a belief you have nothing to learn, and that is not a wall I know how to fly over.

So you think that you could flap a big costume wing held with just your hand with the same level of strength as if you were wearing it as a sleeve, as long as your elbows are tied to your waist, and problems like all that force being applied to your little saddle joint wrist instead of distributed along your entire arm just don't exist? Nevermind that you're also trying to move the entire wing with just the rotation of your hand, the resistance from inertia potentially being enough to literally tear the thing binding your elbow and/or literally break your arms before it budges?

When you use your entire arm, you have a lot more leverage to overcome the inertia of the wing AND you are using your strong upper arms with their strong sturdy ball socket shoulder joints to do it. Your wrist would be destroyed trying to do that, especially repeatedly.

I also don't understand why this is necessary at all. I'm pretty sure there's a swift-like pterosaur that just has short arms and a really long wing finger, and just like saucebacks, they walk on their wings.

Wait, have you been making the assumption this whole time that flying saucebacks twist the pseudo-digitigrade ankle equivalent and not the true ankle and wing toe to adjust in flight? You know the "raised heel" is basically filling the role of the elbow, right?

QUOTE (Disgustedorite @ Jan 30 2023, 09:37 AM)

I also don't understand why this is necessary at all. I'm pretty sure there's a swift-like pterosaur that just has short arms and a really long wing finger, and just like saucebacks, they walk on their wings.

The pterosaur Anurognathus, perhaps? That depends on just how short counts as "short".

QUOTE (Disgustedorite @ Jan 30 2023, 08:09 AM)

Wait, have you been making the assumption this whole time that flying saucebacks twist the pseudo-digitigrade ankle equivalent and not the true ankle and wing toe to adjust in flight? You know the "raised heel" is basically filling the role of the elbow, right?

I personally was interpreting what was being said on your end that twisting in and of itself was being rejecting in favor of a limb that could only move in a 2d plane entirely. With no segment able to break that plane.

If this were a misinterpretation it's where, in my mind, the comparison to an insect wing previously made would have come from.


I think giving names to each bone could be something worth doing since we have a skeleton now.

Muscles sounds more tedious to me since they're not in rows.



This post has been edited by colddigger: Jan 30 2023, 12:21 PM