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Noob question: is a bone a single point or the conncetion between two points?


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Sorry if this is a dumb question but I couldn't find an exact answer on google!

Are bones in a rig technically individual points/nodes or are they counted as the connecting lines between two points/nodes? For example, if I've got this biped rig below, would this leg count as having 4 bones (in red, the connecting lines between two points/nodes) or would it count as 5 bones (in blue, each individual point/node in the bone chain)?


I'm working on a character rig but need it to work on iOS devices, and I've read that iOS only supports up to about 32 bones per rig... so I'm trying to count my rig's bones exactly to make sure I'm not over that limit. ?


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Not sure what the "point" terminology means.  A bone is basically a rotation, position, & scaling that is spread over the vertices that list it as an influencer.  A vertex may quality that influence in percentage terms & may have more than one influencer.

In BabylonJS, bone do not even record the blue values, so I guess the answer to your question is the red set.

BTW, in BJS the safest you really need to keep your bones around 23 / 24 as a max for iOS, unless you know Apple is going to support WebGL 2.0 within your time horizon.  32 is the virtual max, but that would leave zero vertex shader uniforms for anything else.  I seriously doubt any other WebGL framework can do much better.

If that is not something you can live with, you might build a native app, or possible PR changes to WebKit, if that is a thing.

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Ah, that's really good to know!

Sorry for the bad description, I don't know the right terminology it but by "point" I mean like how in the picture above the leg has 5 "points" (or joints, I guess) labeled in blue that define its rig (1: hip joint, 2: knee joint, 3: ankle, 4: toe knuckle, and 5: toe tip) but that means it has 4 "connections" labeled in red between those 5 points (1: between the hip and knee [basically the femur], 2: between the knee and ankle [basically the shin], etc.).

So when BJS/WebGL is counting all the bones toward that 23/24 limit, it'd count the numbers in red (the "connections" between the points/joints) and not the numbers in blue (the individual points/joints) on the rig, right?

I'm still new to WebGL but trying my best haha, thanks for clarifying this for me.

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