Moving Separate Parts of Human Model: Page 2

Moving Separate Parts of Human Model

TwistedTwigleg

Okay, I think I got an example working! It is a bit rough, but it uses a Quat set with individual values (four sliders in this case) and the lower arm correctly follows the upper arm's rotation.

I've attached the project to this comment :smile:

mec

@TwistedTwigleg I don't know how to appreciate you, a simple thank you won't cut it but huge thanks for everything. I will test it with my own model and sensor data and I will come back with results. Kind Regards Mason

mec

Hey @TwistedTwigleg Recently I implemented IMU data on Skeleton Project which you kindly built, In this gif I attached two IMU sensors to my arm and forearm and its done. I'm gonna attach the results down here: Appreciated yet I have some question about the project You added two spatial nodes Bone_UpperArm and Bone_LowerArm and attached a script for both of it. I want to know the reason Regards Mason

TwistedTwigleg

Awesome, I’m glad it’s working!

yet I have some question about the project You added two spatial nodes Bone_UpperArm and Bone_LowerArm and attached a script for both of it. I want to know the reason

Sure. The script on each of the Bone_ nodes is a script that simply takes the GlobalTransform of the Spatial and applies it to the bone. I wrote the script so it could work with any bone, and simply by changing the exported variables you could change which bone the node effects.

The reason I did it this way is that I find it’s more flexible. The same script can be used for as many bones as you want to influence, you just need to make a Spatial node per bone and assign the exported variables. The other reason for doing it this way is that it keeps the code that changes the GlobalTransform separate from the code that applies it to the bones, which also makes the code a little cleaner in my opinion.

That’s the reason why though! It is totally possible to control both bones through a single script, it’s just not the route I took for the example project.

mec

Hi again @TwistedTwigleg , I hope your well, Would you please say some more information about BoneAttachment node that your using in projects. What should I do for moving whole left and right arm in the same time?

Regards Mason

TwistedTwigleg

@mec said: Hi again @TwistedTwigleg , I hope your well, Would you please say some more information about BoneAttachment node that your using in projects.

Sure!

I am using a custom Bone3D like node for my projects, specifically for my IK plugin Twisted IK 2. The bone setting part of the node is pretty simple, it attaches a signal to the idle_frame or physics_frame signal in the SceneTree, and then uses that to apply and then get the global pose transform.

There is a bit more to it for IK related stuff, like getting the bone length and correctly rotating the bone directions so forward for the bone is -Z even if the base model uses a different bone forward axis, but that’s really mostly just extras. The important parts is converting the transforms from a GlobalTransform to a GlobalPose (which I think my example had code to do?) and setting up the scene correctly so child bones nodes are correctly modified by their parent bones nodes.

What should I do for moving whole left and right arm in the same time?

The easiest solution is to recreate the bone hierarchy exactly as it is in the 3D file. For example, if you want to move the whole left arm, then you’ll want something like this as your Bone3D-like nodes:

= Shoulder_Left == Forearm_Left === Lowerarm_Left ==== Hand_Left ===== Etc = Shoulder_Right == Forearm_Right ==== Lowerarm_Right ===== Hand_Right ====== Etc

Then you want to follow and apply the bones in the correct order. If you have it like the example scene tree setup above, then it’s normal process order should be fine, as it will do the children and then the parents as expected without any issue. The reason it has to be like this is because the global_pose_override only affects the bone it’s applied to, so child bones use the non override pose and then become detached and look visually strange.

In Godot 4.0 this won’t be totally necessary, as you can override the local pose using set_local_pose_override, but this function isn’t in Godot 3.X and so recreating the bone hierarchy in the scene is sadly the only way to replicate the functionality where you can modify bones and have all the children bones correctly update.

Hopefully that helps and makes sense! If anything isn’t clear, do not hesitate to ask and I’ll do my best to answer when I have the time :smile:

mec

Hi again @TwistedTwigleg First of all, appreciation for previous project that's really handy for me. I need to combine the previous project (bone transform) with IK. I tested the IK node in GODOT and that was not really idle for me. So I just remembered a Orthopedic doctor and decided to ask him? What's your thoughts?

Kind Regards,

Mason

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