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QUOTE (Disgustedorite @ Oct 21 2022, 01:22 AM)

What is going on at the knee? Is it the perspective or is the gastrocnemius wrapping around the bicep femoris? It almost looks like the gastrocnemius attaching to the front of the femur instead of the back or... looping around it?

This was evo's response:

QUOTE

the gastrocnemius attaches to the femur over the biceps femoris yeah

QUOTE (Jarlaxle @ Oct 20 2022, 07:56 PM)

QUOTE (Disgustedorite @ Oct 21 2022, 01:22 AM) What is going on at the knee? Is it the perspective or is the gastrocnemius wrapping around the bicep femoris? It almost looks like the gastrocnemius attaching to the front of the femur instead of the back or... looping around it?

yes the gastrocnemius attaches to the lower outer part of the epicondyle and the biceps femoris attaches to the proximal end of the of the tibiotarsus

QUOTE (Disgustedorite @ Oct 21 2022, 02:20 AM)

This was evo's response: QUOTE the gastrocnemius attaches to the femur over the biceps femoris yeah

Hmmm so straight away I see two options:

1. Do the wrap around from the gastrocnemius which would entail moving it to the to the base of the femur and extending it along the hip

2. Extend the bicep femoris to wrap around the tibia but tuck the wrap around underneath the gastrocnemius

Since it can pull both muscles without constricting each other around the knee right now, the same should still hold true along the tibia?

QUOTE (Evolutionincarnate @ Oct 20 2022, 08:36 PM)

QUOTE (Jarlaxle @ Oct 20 2022, 07:56 PM) QUOTE (Disgustedorite @ Oct 21 2022, 01:22 AM) What is going on at the knee? Is it the perspective or is the gastrocnemius wrapping around the bicep femoris? It almost looks like the gastrocnemius attaching to the front of the femur instead of the back or... looping around it? yes the gastrocnemius attaches to the lower outer part of the epicondyle and the biceps femoris attaches to the proximal end of the of the tibiotarsus

!!!
Is this...
The first post of Disgustedorite's illustrious "bone friend"?

QUOTE (Evolutionincarnate @ Oct 21 2022, 02:36 AM)

yes the gastrocnemius attaches to the lower outer part of the epicondyle and the biceps femoris attaches to the proximal end of the of the tibiotarsus

Going by this I guess if the bicep femoris is already attached to the tibiotarsus it makes more sense to extend the bicep femoris and tuck the wrap around under the gastrocnemius

This also means I should replace the mentions of the tibia with tibiotarsus... What about the cannon bone / metatarsal?

Also hi

This post has been edited by Jarlaxle: Oct 20 2022, 07:45 PM

I placed the bicep femoris wrap under gastrocnemius, changed the bone names, fixed the bones that shouldn't have looked like they came from fusing other bones, and the mysterious knee caps that apparently came from nowhere have now left us to retire in nowhere.

This post has been edited by Jarlaxle: Oct 21 2022, 03:17 AM

QUOTE (Jarlaxle @ Oct 21 2022, 05:00 AM)

I placed the bicep femoris wrap under gastrocnemius, changed the bone names, fixed the bones that shouldn't have looked like they came from fusing other bones, and the mysterious knee caps that apparently came from nowhere have now left us to retire in nowhere.

what is the crank here? what solid structure is that representing? since you said earlier that rabbits have that but they definitely dont.

https://iopscience.iop.org/article/10.1088/1748-3190/abf744


Is this helpful?

I haven't looked into what's being discussed here too thoroughly, but it's something to do with comparing limbs to moving contraptions, and skimming this it seems to be a similar topic.

QUOTE (Evolutionincarnate @ Oct 21 2022, 06:45 PM)

QUOTE (Jarlaxle @ Oct 21 2022, 05:00 AM) I placed the bicep femoris wrap under gastrocnemius, changed the bone names, fixed the bones that shouldn't have looked like they came from fusing other bones, and the mysterious knee caps that apparently came from nowhere have now left us to retire in nowhere. what is the crank here? what solid structure is that representing?

The crank is the narrow band of muscle at the end of the muscle wrap acting as an elastic band - perhaps slingshot might be a better comparison - it can only pull or be pulled and restricts the motion at its into circular motion, luckily for the visorbill at no point during the flap or hop cycle does it need to push.

Were you given the explanation prior to the last description update in the OP or was it based on the current description? I'm not expecting that you'd read everything prior to joining - that wouldn't be a fair expectation -but I do need to know if the last clarification regarding the nature of the crank isn't doing its job of conveying the information.

QUOTE (colddigger @ Oct 21 2022, 07:43 PM)

https://iopscience.iop.org/article/10.1088/1748-3190/abf744 Is this helpful? I haven't looked into what's being discussed here too thoroughly, but it's something to do with comparing limbs to moving contraptions, and skimming this it seems to be a similar topic.

Ooh, only skimming it for now in a yet to be fully caffeinated brain state, but from first impression that is both spoilery for existing evil future plans and potentially inspirational for more evil future plans.

The broad overview of 4 link mechanisms is applicable – and they are making the same disclaimers I keep needing to make here regarding flexible links vs rigid links - but the specific examples they go into in-depth are not the same ones I am using for the visorbil.

We absolutely need to tap them in the future of sagan though, saving this for a more thorough reread.

edit:
Updated the anatomy diagram in the description, replaced tibia with tibiotarsus and metatarsal with cannon bone, hopefully we'll stick with these bone labels and make them... cannonical.

This post has been edited by Jarlaxle: Oct 21 2022, 02:59 PM

I'm pretty sure the issue is that the mechanism doesn't actually work in the form presented nor is it even remotely what rabbits do so you don't have that justification.

QUOTE (Disgustedorite @ Oct 21 2022, 11:05 PM)

I'm pretty sure the issue is that the mechanism doesn't actually work in the form presented nor is it even remotely what rabbits do so you don't have that justification.

I am greatful... That our education system includes basic high school level physics, still kind of jelly that american students operate on frogs though.

Anything more specific for me to address?

This post has been edited by Jarlaxle: Oct 21 2022, 03:29 PM

QUOTE (Jarlaxle @ Oct 21 2022, 05:28 PM)

QUOTE (Disgustedorite @ Oct 21 2022, 11:05 PM) I'm pretty sure the issue is that the mechanism doesn't actually work in the form presented nor is it even remotely what rabbits do so you don't have that justification. I am greatful... That our education system includes basic high school level physics, still kind of jelly that american students operate on frogs though. Anything more specific for me to address?

the problem is that rabbits have no linkages like any described in the paper beforehand or anything similar to what you describe
the anatomy you have described doesnt make sense because your having a muscle form a link that needs to be rigid in order to do what you say it does

the biceps femoris in rabbits just pulls the leg back and the lower leg toward the origin at the pelvis

This post has been edited by Evolutionincarnate: Oct 21 2022, 04:18 PM

QUOTE (Evolutionincarnate @ Oct 22 2022, 12:18 AM)

QUOTE (Jarlaxle @ Oct 21 2022, 05:28 PM) QUOTE (Disgustedorite @ Oct 21 2022, 11:05 PM) I'm pretty sure the issue is that the mechanism doesn't actually work in the form presented nor is it even remotely what rabbits do so you don't have that justification. I am greatful... That our education system includes basic high school level physics, still kind of jelly that american students operate on frogs though. Anything more specific for me to address? the problem is that rabbits have no linkages like any described in the paper beforehand or anything similar to what you describe the anatomy you have described doesnt make sense because your having a muscle form a link that needs to be rigid in order to do what you say it does the biceps femoris in rabbits just pulls the leg back and the lower leg toward the origin at the pelvis

...Which restricts the distance at the back of the foot from the pelvis and forces it into circular motion, the only force being applied on it is tensile. It pulls and gets pulled, it doesn't need to be rigid because it doesn't push.

If for some reason you've tried reversing the action and energizing the visorbill by tying the base of the hip attachment of the muscle to a motor thereby making the crank the source of the motion, then the flexibility of the bar and its inability to push would be a problem. Thankfully, nothing the visorbill currently does is so torturous.

QUOTE (Jarlaxle @ Oct 21 2022, 06:37 PM)

QUOTE (Evolutionincarnate @ Oct 22 2022, 12:18 AM) QUOTE (Jarlaxle @ Oct 21 2022, 05:28 PM) QUOTE (Disgustedorite @ Oct 21 2022, 11:05 PM) I'm pretty sure the issue is that the mechanism doesn't actually work in the form presented nor is it even remotely what rabbits do so you don't have that justification. I am greatful... That our education system includes basic high school level physics, still kind of jelly that american students operate on frogs though. Anything more specific for me to address? the problem is that rabbits have no linkages like any described in the paper beforehand or anything similar to what you describe the anatomy you have described doesnt make sense because your having a muscle form a link that needs to be rigid in order to do what you say it does the biceps femoris in rabbits just pulls the leg back and the lower leg toward the origin at the pelvis ...Which restricts the distance at the back of the foot from the pelvis and forces it into circular motion, the only force being applied on it is tensile. It pulls and gets pulled, it doesn't need to be rigid because it doesn't push. If for some reason you've tried reversing the action and energizing the visorbill by tying the base of the hip attachment of the muscle to a motor thereby making the crank the source of the motion, then the flexibility of the bar and its inability to push would be a problem. Thankfully, nothing the visorbill currently does is so torturous.

the biceps femoris doesnt limit range of motion though, it just pulls the leg back and bends the lower leg, there is no circular motion in this
and applying this to flight would require the entire leg to be rotated with the leg facing inward
the mechanism your trying to propose doesnt work the way you have suggested, its facing the wrong direction, and it doesnt provide any advantage over the current method of flight in sausophrey