Hey guys. I’m sure someone with experience can look at this and in two seconds tell me what I’m doing wrong, I’ve managed to get just about every other part of the body deforming naturally looking but I’ve tried noodling this a bunch of different ways, and I just can not figure out how to get the thigh to crease the way it’s supposed to when the leg lifts. No matter what I try the only result I can get is it clipping up into the body. I’m sure it’s either my topo or my weight painting. Would appreciate greatly anyone who can point out what I’m doing wrong.
Hi and welcome, Can you share a link to your file?
You can use the blur brush to smooth the weights between the two bones.
https://www.youtube.com/watch?v=5SLlp3AwShM
Hey! Thanks for responding! The blend file can be found here:
I’ve tried to make sure I included the loops everyone recommends, but in particular this area where the thigh meets the pelvis, I’m really struggling to figure out how to get the skin to pinch in rather than just clip. I’ve been trying to keep it low poly since I’m most interested in game assets, but I feel like I probably need more geometry in the area, I’m just not quite sure where.
dudeTest.blend (3.8 MB)
This any closer to what you’re looking for?
All I did here was adjust the weights. Changing the loops around/adding more would probably also help.
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yeah! Thanks for taking the time! This is much closer to what I was expecting, and yeah it looks like I need to mess with my loops some. I’m noticing you blended some of the weight of the top of the leg into into the pelvis. I’m thinking I don’t quite have a great grasp on exactly where each bones influence should be. Most of the resources I’ve found for weight painting don’t seem to get too specific about that; more focused on the use of the tools, and I’ve just been relying on my own intuition about human anatomy for putting it into practice. Any chance you know any good tutorials on that? Seems there’s plenty on topology, but weight painting info is comparatively sparse.
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Yeah! Thanks! much closer to what I was expecting. So, I wouldn’t have thought to let the pelvis influence go so low, it seems I’m not really understanding exactly what bones should be influencing what just using my intuition about human anatomy. I have found much in way of really specific info on this topic in the way I have with topology, any chance you know any good learning resources for the weight painting aspect?
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IIRC, there’s also a bit of pelvis in the thigh. Mostly I went back and forth between the two until the clipping was reduced.
Not in particular. Sorry. For the most part, my “technique”, such as it is, doesn’t differ too much from yours.
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Yes the balance between the pelvis and the thigh bone weights is a trail and error, i probably have gone slightly further down then needed.
The only way in my opinion you will learn to find the right balance is by keep practising it, and correcting your mistakes, each joint has it’s problem and of course your model needs to be made to allow for the bending and stretching.
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Hi and welcome to the forum.
Well, Rigging, and notably Organic Rigging, can get extremely complicated so often, for plenty of different reasons.
One reason which must be known, is that the Skinning methods/algorithms which are conventional in CG softwares (and that Blender also uses), are deeply inadequate, when it comes to spontaneously mimicking good form, for all sorts of organic shapes-in-motion. Basically, ‘Stone Age’ (ok, maybe, ‘Neolithic Age’) maths for Rigging.
Because of such reality, the majority of riggers, if they want to achieve real, fine results, they are obliged to engage in all sorts of Corrective methods, in order to provide at least decent Deforms on the Rigged Model, but especially on the Joint Regions which suffer more from Artifacts due to excessive Rotation of the Deforming Mesh on the Joints. In Blender, Skinning Deforms are related to Armature Deform; and Weight Paint is just a generic Vertex Data, that will be calculated according to the Skinning method taking place. While some Joint Regions tend to be easier to Rig than others, the Pelvis-Femur or Hip-Thigh Joint, that you are attempting to Rig with realism, is probably one of the hardest challenges in Organic Rigging. And it can also be a giga-rabbithole. There is also the problem of the “Deltas”: the software is just not smart enough to identify ‘Diagonal Axes’ on its own: it needs to be ‘tutored’! with special Rigging techniques, only then [and after a lot of more headaches! including improved Weight Paint output], the Corrective methods can be ultimately rendered more effective in a more complete Rigged Model.
Of course, a lot depend, as folks here already indicated properly, on how far do you want to go with the quality of the Deforms, and to which extend (e.g., Angle) the Leg needs to Rotate in relation to the Lower Torso, and which Orientations and Directions or Leg Rotation to favor more or less. In that sense, it is not incorrect to say that, plenty of Rigged Models out there, could just be solved with just some better Weight Paint, since not a lot of extreme Leg motions might be required. But, for the REAL Deforms (not even mentioning Contortionism), there are currently no shortcuts that I know. It’s gets Organic Rigging really hard; because of how the Rigging systems were conceived to start with.
So, the ‘traditional’ way (because straight to the point and versatile regarding most Exportation projects) to solve those Skinning Artifacts, I believe is the Corrective Shape Keys method. It’s far from ideal, but it can get some crucial job done, whereas Weight Painting alone is most likely insufficient in the case of a Complex Joint such as the Hip-Thigh one. But even Corrective Shape Keys will require Deltas; it would be like, ‘Correction of the Correction’. 
This is how archaic Organic Rigging is; and this is not only a thing in Blender btw, although it is almost certain, that out there there exist software more dedicated to Organic Rigging.
Maybe, you should start out with Corrective Shape Keys method (then with additional Deltas), and see what you can achieve, and see from there, if you can at least Rig the Hip-Thigh with some organic precision. Because Corrective Armature Deform (doing with Corrective/Helper Bones), tends to be way more complicated without good orientation (and excellent time resource).
I’ll suggest you some content here if you are curious enough, because this is a very important topic. The Mesh Topology of the Crotch, Pubis and Upper Thigh you’ve made, in my opinion, sounds a fine starting point, but I haven’t made later tests to confirm that approach entirely.
In my Guide in this link:
look for “Pelvis” and also “Delta”; you’ll find additional information along with these same links:
There are also a few other tutorials which are good mentioning:
Of all that I’ve presented, none of them solutions are ideal if you ask my opinion; there are always fierce drawbacks; whether some extreme (or not so extreme) Rotation Poses for the Legs will be missing, or there would be lacking Deltas, or the Setup is really hard to reproduce. This next is just an example Worflow of how long it can take, experimentally, to achieve something more adequate, even with some experience:
In the near future, I’m looking forward to a new Setup, which can combine all that I’ve been learning, which might become a new tutorial on the subject for Blender.
Hope that helps!
WOOOOAAAH! Thanks homie!!! I will definitely be digging into all this!
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