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I'm a beginner and I'm having problems with creases when moving joints. Here are some examples (Blender 2.8)

Screenshot 1 screenshot 1

Screenshot 2 screenshot 2

Screenshot 3 screenshot 3

Screenshot 4 screenshot 4

Screenshot 5 screenshot 5

I tried to change the weights, but it didn’t work. Tell me how to set up the normal operation of the armature.

Blunder
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Zimaell
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    I'm not clicking on strange links. Please just paste images here, no need for 3. party image hosts. (if they are images) – Frederik Steinmetz Dec 10 '22 at 13:03
  • Is this a Rigify metarig? This rig is not for animation. You need to generate the actual animation rig. Another thing, if the arm is raised more than 90°, the shoulder bone must also be raised. – Blunder Dec 10 '22 at 19:55
  • If I understood you correctly, then for a smoother position of the skin, you need to add additional bones, I have seen something similar where the upper part of the arm consisted of two parts, this makes sense, although it complicates the process, but since the result is more important, this option is not bad, just a question - and how then these bones should be called so that the animation works correctly? And also how should kinship be established? I have so far quickly watched the video that you recommended to me (Muscle Flex Rig and Animation - Full Timelapse), it’s just with the addition – Zimaell Dec 10 '22 at 19:46
  • what does "This rig is not for animation" mean? Are there rigs specifically for animation? which ones? how to generate them? – Zimaell Dec 11 '22 at 08:05
  • Rigify's real rig is the animation rig. It's a common misunderstanding to use the metarig for animation. You need to generate it from the metarig. Have a look here: https://blender.stackexchange.com/a/215051/107598 -- here https://blender.stackexchange.com/q/275168/107598 -- and here https://blender.stackexchange.com/q/279008/107598 -- There is also CloudRig which is a feature set (extension) of Rigify. It was used for the Sprite Fright movie. And there is BlenRig. It was used in early movies. Lastest version is BlenRig 6. It has a setup guide. I haven't tried it yet. – Blunder Dec 12 '22 at 04:03

1 Answers1

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You can definitely reduce the creases by tweaking the weights a little bit, but you can't remove them completely with your current armature setup.

Do understand that vertices just follow your bones' transforms. Weights just control how "strong" is the influence. The creases are here simply because the vertices do what you ask them: you rotate an arm bone, so the vertices rotate around the bone.

There are ways to make these weird deformations go away. To make it simple, let's say there's the hard way of simulation, and the simple way of manual correction.

The hard way

The most accurate but hard way is to actually simulate the physics of the skin sliding around with muscles contracting and moving around. That's complex to setup and definitely have quite an impact on performances when animating, but it's ultimately the most accurate.

There are addons that do it well, like X-Muscle, but it's often a few bucks to spend.

X-Muscle System 3.0 - Blender Market

You can do it manually, it's basically a matter of creating your muscle as meshes, bind them to your bones, inflate them as they should with shapekeys, and use a shrinkwrak modifier on the skin mesh with a vertex group to snap the corresponding area of the skin onto the muscle.

The simpler way

It's not "simple" as in "easier for you", that only depends on the level of complexity and realism you want to achieve. But it's definitely easier to set up.

Instead of trying to recreate how the skin actually behaves in real life, you can instead try to "correct the shape". Two main ways to do that: adding bones here and there that you can manually move around to bump up/down areas (or sometimes can automatically replicate some muscle contraction or skin slides like we can see there: BLENDER - Muscle Flex Rig and Animation - Full Timelapse - YouTube), or make what we call "corrective shapekeys" to fix the mesh when the bones are in a particular rotation or position.

Basically, put your bone in a position that creates an issue (I.E. your left arm rotated upwards), create a shapekey that fixes the arm crease, and then make a driver on the shapekey's intensity so that it activates depending on your arm bone's rotation.

More about it: Corrective Shape Keys - Blender 2.8 Tutorial - YouTube

I have limited access to Internet and Blender right now, so I can't really detail more than this. But let me know if you need more, and I will come back later to edit my answer, if nobody already made it up by then.

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