Full body FPS player rig. Control over arms issues.

MikeCL

Hi all!

So I'm working on a project (FPS) that requires a full-body player.

I'm trying to get more dynamic control over the arms for the player. I'm trying out a solution for the arms using the LookAtModifier3D node. Generally, it works, but I don't seem to have any control over how I want the bones to rotate. Looking at the video example that shows my issue, it adds rotation to the Y axis, which I don't want.

Is there a way to restrict/lock the axis rotation of bones when using the LookAtModifier3D node?

Or is there a better approach to get more control over the skeleton?

xyz

MikeCL What happens if you disable use_secondary_rotation on the modifier node?

kuligs2

MikeCL how would you control the joints in game? Is this some VR full body tracking type thing where you want to bind the tracking to the bones in game or somehow dynamically animate weapon translation while people aim? Maybe just use transforms? Add bone attachment node for weapon and transform the rotation? LookAt3D is kinda new, before it, you could rotate things with transforms.. have more control, but then another headache to wrap your mind around oiler angles.. i cant help you with that 😃

Tomcat

MikeCL So I'm working on a project (FPS) that requires a full-body player.

A new project is great! 🎉

But why does an FPS need a full body?

MikeCL

xyz Made another video, showing the default state (without the look at) and also including switching the secondary rotation off.

kuligs2 No VR. Just FPS with full body. So the idea is to have more precise control for the arms while still blending in nicely with the animations for the body. This way, the positioning of the weapon can be tweaked with different states directly in the engine instead of having to do that in the animation. On top of this, it enables more things to be done dynamically in general.

kuligs2 Maybe just use transforms? Add bone attachment node for weapon and transform the rotation?

Not sure how that would work for the hand bones? I can offset the weapon with no issue. But the hand holding the weapon needs to be aligned with it 😛

Update:
Just another video to show where the look at marker is. So it's pointing at the correct direction. Just the Y axis rotation I'm trying to fix.

Looking more closely when switching off secondary rotation. It seems to be rotating only at the X axis.
I've also tried switching the Forward and Primary rotation axis around.

xyz

MikeCL You can try with SkeletonIK3D instead. There you have direct control over target basis.

MikeCL

xyz Ah yes.. I use that for the upper body control. I'm a bit reluctant to use it, though, as it has been marked as deprecated. I did a quick test with it with the hand as root and the palm bone as tip.. Unfortunately, the palm bone gets wacky for some reason.

xyz There you have direct control over target basis.

Hmm. how do I control the basis? I tried but I can't seem to be able to? I did a quick test adding a lookat node to control the Y Angle. Worked somewhat, but doesn't feel robust.
Update: Silly me. It just adapts to the target node. 🤦‍♂️

Before setting up the LookAt nodes for the hand and elbow (the elbow works fine), I used IK for the entire arm. It was just way too unreliable and could generate crazy results in some angles. But maybe I should give it another go. Not sure why it's deprecated, though, very odd decision. Perhaps someone here knows the reason?

Tomcat It's a fun project. I hope I can reveal soon! It's a multiplayer game. So full body for several reasons. 1 is so the player can see its own body when looking down etc. Also I can reuse a lot of animations. And on top of that, customization, full body avatars etc.

Tomcat

MikeCL 1 is so the player can see its own body when looking down etc.

You don't need a full body for this either. But if it's multiplayer, then you might want to consider replacing the body for first-person and third-person views (this is done much more often in games than you might think). And yeah, I also wanted to suggest paying attention to IK.

xyz

MikeCL Not sure why it's deprecated, though, very odd decision. Perhaps someone here knows the reason?

I think it's just a disclaimer for possible breaks of future compatibility, as they're probably planning to make some more generalized system. It's not that it doesn't work properly. I've used the node and it functions just fine. It's just a simple FABRIK implementation. Not much can go wrong there.

Here you can use it with a single joint chain and it should let you explicitly control the orientation when pointing.

Tomcat

MikeCL Not sure why it's deprecated, though, very odd decision. Perhaps someone here knows the reason?

They didn't like something there and want to redo it. There was a thread about it, but I can't find it now.

…

Here, I found it:

https://godotforums.org/d/42618-resources-on-inverse-kinematics-in-godot-45-skeletonik3d-deprecated

MikeCL

So I found my solution.

I did go back to using IK for the arms. But I gave up on Godot's own IK system. Did some digging, and it seems there's a regression in the IK implementation transitioning from 3.x to 4.x. And since it's deprecated, they are moving on to other solutions that will eventually replace it.

https://github.com/godotengine/godot/issues/69752

I went with this addon for my IK needs, and it seems to work great so far.
https://github.com/monxa/GodotIK

No strange jitter or janky behavior.