The issue with that is it would make implementing animation harder- atleast I would think
So you dont consider the contact surface with that medium?
Why not just curve bones then? In my mind this would need alot of joints to make a proper curved bone. Wouldnt a bone tool do that too?
This model seems like that model itself just with minor diffs.
What do you mean with forces applied to the bones?? It could mean many things.
I haven’t some up with an equation to determine the surface area of the entire creature.
because a lot of what I’m doing here is supposed to fit into graphics and animation. The segments have a certain width & height which can be used to construct a mesh. Then, the bones can be animated using a sine wave based on where they lie on the anguiliform to thuniform spectrum. Curved bones would certainly be possible, it’s just not really a priority in my mind.
Yeah. it is. The only reason I call it a ‘fish accordion’ model is because it’s a fun name for it.
When I say forces applied to bones, I’m talking about the muscles that span from one rib to the next. The force applied to each rib would be proportional to the width of the rib, the stiffness of the joint, and the flexibility of the rib itself. It would be possible to add all the forces applying to that rib, but it doesn’t have a good simulation complexity to simulation accuracy ratio.
It would make animating fish much easier. In simple fish, their movements tend to fit into a spectrum between anguiliform, and thunniform, which can be easily animated with sine waves.
here’s an example:
https://oceantracks.org/sites/oceansofdata.org/files/Thunniform.png
There are some more difficult animations, though. In Stultus Douspedes, It’s not entirely clear whether it would swim like an octopus / jelly fish, a frog, or a regular fish.
Going back to this, I was actually imagining a metaball-esque system for constructing the mesh. Each segment would have a height and width, which would ‘wrap around’ the bone, and act as a layer of soft tissue. Then, you use the metaball algorithm to connect the sperate spheres together to form a mesh which would be the model of the creature.
Curved bones can also be used to construct a mesh tho.(width+section surface+radius)
And in my opinion we shouldnt limit ourselves to known swimming methods in animals. We should let the randomness and players try new ways.
Uhm why couldnt this model be applied to normal bone-joint-muscle model??
I know. They’re just difficult. like I said,
That was my description of the bone-joint-muscle model. Like I already said,
It is essentially just the bone-muscle-joint model.
with this only bare in mind we would eventually move onto a polygonal skeleton based system known as Convolution Surfaces. Reason being, metaballs are fantastic for multicell, horrible for larger animals who aren’t blobby and round. Basically, just keep things ordered and structured enough to where we can abstract things in terms of points and lines (with each point having a weight, or radius if that helps you picture it) and we’ll be good.
1 Like
Kind of offtopic…
I’m not going to add any tutorials to any prototypes. Tutorials are the thing you should do last to polish things up when game mechanics aren’t very much a work in progress.
I’ve never heard of a convolution surface. do you have a good resource to learn about them?
The first post in this thread has an overview:
thanks!
I only have the papers I used to help me program them. There is a thread about them on this forum (there’s even a PyGame demo) but to truly understand you have to read the papers. This is the clearest most basic one: Convolution Surfaces based on Polygonal Curve Skeletons (inria.fr)
You said theyre not a priority not how difficult they are… anyway, i dont think we should let difficulty set us back even so for a more general model.
Youve confused me here, so in your model the force applied on the bone isnt considered?
If so why would we have even consider it in the first place for the model.
In a bone-joint-muscle model, the forces to each bone are added together, and then used to calculate the rotational force that the joint can exert. My model skips adding multiple forces, and just assumes the total inline forces adds to zero. The force each muscle applies is considered, but the forces that would contribute to stress on the bone are ignored.
edit:
you’re free to do that. I probably wont be able to implement the model by myself, but you can add stuff if you want to.
??? Huh? the muscles moves the bone and exerts a force not the joint?
Why would you add multiple bone forces on a single joint for multiple directions? You consider the muscles relevant to that direction you want to move.
Why would you consider this?
Yes, because in animals, joints cannot exert force. A muscle contracts to create the force that turns the joint.
Because joints are turned by an unequal force along the direction of the joint. When a joint turns, it’s because muscles are contracting one one side, and not the other.
because I add the force the individual muscles can exert to get the total force the muscles can exert.
1 Like
Thats what i said…though… haha. You said that the joint exerts force xD
You mean by a force, not an “unequal force”
Sorry i meant why would you even consider forces stress on the bone.
This can be calculated in-editor, to determine minimum bone strength.
Okay the diagram clears things up a bit, but it shows that you consider the forces between 2 joints and all the joints in between are ignored mathematically and just animated. Did i understand right?
So it only works for fishes not all locomotion types.
In the first part of the picture i dont understand what you mean by forces cancel out.Becaues they dont, they add more movement range to those joints.
I’m saying that in terms of forces, the center bone doesn’t contribute to the force, so you can just ignore it, and assume the force is directly transferred from the first to last bone.
Ok i understand now, but as i said i think this only works for simple predefined actions and movements. (fishes). The interaction with terain/other objects, will change things…