Timeline for My Model's Forearm Twists Too Much
Current License: CC BY-SA 4.0
17 events
| when toggle format | what | by | license | comment | |
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| Aug 28, 2021 at 21:44 | comment | added | Blunder | You could use drivers to automate the bone rotations (youtu.be/_T9RURzspP4). But I have no idea if this is a good idea for a Rigify rig. I know you can customize Rigify but you should know what you're doing else things can break. For the question about "the IK matches the rotation of a held object" I suggest posting another separate question. | |
| Aug 28, 2021 at 18:21 | vote | accept | user1539405 | ||
| Aug 28, 2021 at 15:19 | comment | added | user1539405 | @AlexandreMarcati So, I added an "EDIT5" in the original post with the changes. Compared to the edits you made to the model it still looks worse, so I'm wondering if that's down to additional modifiers for your own convenience? Aside from that it'd be great to know if there's a good way to set up the elbow target IK to work with hand rotation | |
| Aug 28, 2021 at 3:48 | comment | added | user1539405 | @AlexandreMarcati Thanks a lot for the update! I'll have a go at making the changes tomorrow. Is there any way to integrate the range of motion for rotation into the IK of the hand? It'd be nice to have the example animation you have be possible as the IK matches the rotation of a held object, for example. | |
| Aug 27, 2021 at 13:18 | history | edited | Alexandre Marcati | CC BY-SA 4.0 |
added 60 characters in body
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| Aug 27, 2021 at 13:14 | comment | added | Alexandre Marcati | The resting position is one in which the wrist is aligned with the elbow. For exemple, if you stand in a T-Pose and rotate your hand so the palm faces straight up you will notice your elbow is pointing down. You can then twist your wrist so your palm is (almost) facing straight down without rotating the elbow, but if you try to keep rotating in that direction your elbow will also rotate. | |
| Aug 27, 2021 at 13:13 | comment | added | Alexandre Marcati | @user1539405 the T-pose is not the problem, the problem is that in your exemple you twisted the wrist more than 90 to one side. To TOTAL range of motion of wrist rotation should be 180, 90 degrees to each side from the resting position. | |
| Aug 27, 2021 at 13:04 | history | edited | Alexandre Marcati | CC BY-SA 4.0 |
Added some anatomy info
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| Aug 27, 2021 at 12:11 | comment | added | Blunder | The T-pose is fine. The limbs of your model just need more edge loops as suggested by Alexandre. I've added an example animation. It's just the hand IK and upper arm IK that are keyframed. For a better deformation at the elbows and knees, you can give them extra loops as you did for the knees and change the topology a bit. Have a look here youtu.be/jByzklhVwH8 and here youtu.be/UvjRA0gqhWo | |
| Aug 27, 2021 at 11:53 | history | edited | Blunder | CC BY-SA 4.0 |
note about duplicated vertices + screenshots
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| Aug 26, 2021 at 21:27 | comment | added | user1539405 | Also, added an edit4 for a "palm-forward" model. It'd accommodate holding a hammer, but I am assuming it would have other limitations, or every T-Pose would do this? | |
| Aug 26, 2021 at 20:53 | comment | added | user1539405 | As an example, hold your hand up to the right of your head as if you're holding a hammer, about to swing down on a nail. If you then unfold your arm into a T-Pose, your hand is palm-up. So my current model can't hold a hammer without either the forearm twisting from the default kinematics or my upper arm and shoulder twisting from manual edits. I know this is an issue with my model, but I'm not sure how to fix it. | |
| Aug 26, 2021 at 20:51 | comment | added | user1539405 | Added Edit3 of my twisting more of the arm to accommodate for the movement with the twist moving into the upper arm and shoulder. I noticed I could perform this movement with my upper arm near the shoulder hardly moving at all. I attempted to just rotate the first 3 tweak bones in the arm to mimic this. But I just ended with the twist in the upper arm. So I'm still at the point where I can perform a real action that causes a distortion in the model. I don't expect it to be perfect, but it hurts the most basic motions. | |
| Aug 26, 2021 at 19:46 | comment | added | Alexandre Marcati | If you stand in a T pose and try to rotate your hand so your palm faces up, you'll see your whole arm up to your sholder will also rotate, cause you can't make your palm face up by only twsting your wrist. | |
| Aug 26, 2021 at 19:43 | comment | added | Alexandre Marcati | Well that's because you are twisting the wrist 180 degrees to one side, it doesn't look natural because that movement range is not natural in humans. If you make sure your upper arm and elbow are perfectly still and only twist the wrist, you will notice it only has a range of about 90 degrees to each direction. So from the T pose, it should only rotate in one direction until the palm is facing forward and in the other direction until the palm is facing backwards (actually a little less cause the range is smaller in this direction). | |
| Aug 26, 2021 at 18:58 | comment | added | user1539405 | Added an edit2 to the main image showing the result of this. I think you are right, but my hasty test looks like a twizzler and I have no idea how I'd need to edit the model to make it look natural | |
| Aug 26, 2021 at 18:31 | history | answered | Alexandre Marcati | CC BY-SA 4.0 |