MakeHuman NextGen Basemesh Talk

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MakeHuman NextGen Basemesh Talk

Postby bogdan666 » Sun Apr 21, 2019 5:41 pm

As I've been working with MH, Blender and UE4 for some time now, I've recognized more and more, where the flaws of the current default mesh are.
I've to admit that the bodyshapes of MH-Characters have the best realism/naturalness of all character creation tools available. We should keep that!

But the current base mesh topology/resolution (default rig with adult female genitalia topology, preseve volume/Dual Quaternion Skinning) has some weak points, if you want to make different poses/animations (yoga,stretching arms) for game development.
For example bending knees to extreme positions or raising arms doesn't look as good as it could be.

I've seen some tricks mentioned in the forum that work inside of blender like having multiple armatures for one character and some other blender tricks/modifiers (smoothen,subsurf), but it's for rendering static scenes and blender only.
Especially the knee and shoulder area don't deform well.

And while doing base mesh optimizations, we should also take Dual Quaternion Skinning into consideration, because it's more advanced than Linear Blend Skinning.
Dual Quaternion Skinning can be used with Unreal Engine: https://www.daz3d.com/forums/discussion ... -inside/p4 ,
as far as I know even with Unity 3d: https://forum.unity.com/threads/dual-qu ... ty.501245/
and it's the standard skinning method in CryEngine. And it works with blender as well: "preserve volume". DAZ utilises it too.

It seems as if the characters need a higher resolution, mainly in the knee, butt and shoulder/armpit/breast/clavicle area.
Simply applying targets won't help here unlike with other body parts, where the resolution is sufficient for adjustments by using target sliders.
Even making a shape key has it's limits with the low mesh resolution. And normally shape keys should be used only as a last resort for small corrections, where the rig has its limitations, because they are problematic, esp. with multilayered clothing.
At least the knees and legs can be reweighted to look more or less smooth.

Applying the subsurf modifier in blender is overkill, because the mesh resolution will be unnecessarily high in most mesh parts and for
most (even higher end) computers it would be overkill having a tricount of >135.000 (without clothes) per character in an open world scene with many other characters.
And it would be still not optimized.

Knee area problems could be theoretically overcome by adding additional edge loops (or a more intelligent knee topology), but for the shoulder it's more difficult.
In my opinion most weak points can be solved by increasing the mesh resolution in the critical areas+more intelligent topology+better bone weighting.

A good mesh for comparison of topologies is the DAZ Genesis 8 Mesh, which is optimized for Dual Quaternion Skinning.
Personally I don't like the daz body meshes, because they are too stylized/doll like and don't look like real human bodies, but we can nevertheless
study the rig, topology and weighting approach.

If you want to compare it with makehuman in blender, then simply load a gen 8 default character in daz studio, export it as .dae and import into blender. (it will come without shape keys, but that's ok for comparison purposes)


Now the question is:
Would it be possible to make an additional experimental base mesh, which doesn't even need to fit the current clothing assets if that would be currently too problematic?
I've heard that new topologies can be made, but only without additional vertrices or by subdividing the whole mesh (overkill)?
What do you think about it? How could we refine the current base mesh in order to look more clean and up to date?


Image 1: As you see the daz knee is superior to the mh knee, but reweighting can "heal" the mh knee to a certain degree (and even the leg looks now ok)
Image 2: MH Character has a horrible bulge when raising arms, that could be overcome by a shape key, but the mesh is still not optimized and lacks resolution (looks bad, esp. in game engines (shadow artifacts etc.))
Image 3: Comparison of MH and DAZ Mesh. See the knee differences and look at the clavicle,shoulder,arm and armpit!

Goal: A Default Mesh with optimizations in knee/shoulder area (mesh resolution, mesh topology, weights...) similar to DAZ but with keeping the current MakeHuman Default Body Shape!
Attachments
daz vs mh mesh.png
arms.png
knees.png
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Re: MakeHuman NextGen Basemesh Talk

Postby blindsaypatten » Mon Apr 22, 2019 3:37 pm

The bulge in the torso is caused by the weight painting for the upper arm segments, the area under the arm is painted for these segments, which, in my opinion it shouldn't be as their movement doesn't affect that area in reality. There is also a "reverse-bulge"/dent in the torso when the arm is lowered below the default position, for the same reason. It's been a long time but I'm pretty sure I made some posts here about this specific issue in the past.
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Re: MakeHuman NextGen Basemesh Talk

Postby bogdan666 » Mon Apr 22, 2019 4:43 pm

I've seen your other post, where you tried to change the weight of armpit and knee joint. It looks quite impressive, but sadly it's blender only, because you've used some modifiers, which will not work outside of blender.
And I'm not sure, if we can solve the armpit/shoulder issues with the current topology at all. No matter how you change the weights of the arm/shoulder bones, the bulge will not go away significantly.
Maybe the default rig worsens the bulge as well or is the main culprit and the topology not so bad, because even applying the Catmull-Clark Subsurf and thus increasing the Vertcount to almost 72k didn't reduce the bulge.
Fact is, that we have to bring MH to the next level, so more people get interested in it, as it's currently the only open source alternative for character creation.
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Re: MakeHuman NextGen Basemesh Talk

Postby blindsaypatten » Wed Apr 24, 2019 3:51 am

While the Corrective Smooth modifier certainly improves the result, the weight painting alone gets rid of the bulge, and nothing will get rid of the bulge if you don't fix the painting. As long as the armpit/lat area is weighted for the upper arm 2 bone that area can't help but be distorted as the bone follows it's arc. Just look at the painting for that bone with the arm raised and you can see the direct relationship between the painting and the bulge.

Edit: Also, if the Corrective Smooth modifier does what you want, but you don't want to use it because it isn't available outside of Blender, you should be able to apply the modifier and use the resulting mesh to generate a shapekey which will have the same effect.

PaintBulge.jpg
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Re: MakeHuman NextGen Basemesh Talk

Postby blindsaypatten » Wed Apr 24, 2019 2:28 pm

As for shoulder topology, the MH mesh is optimized for the default pose in the sense that it has a nice evenly spaced mesh when in that pose. It largely maintains the even spacing in the t-pose, due to the underarm painting, but at the cost of creating the unnatural bulge. When the arm and the torso painting don't overlap (arm on right in the image) you end up with a stretched area (middle image, right side) and the main effect of the corrective smooth is to even out the spacing (bottom image).

Also note that as well as the bulge below the shoulder, there is also a big "dent" in the top of the shoulder, also caused by the painting, primarily the painting for upper arm 01 in this case.

One of the things that stands out for me is the alignment of the mesh with the real "crease line" between the legs and torso in the DAZ mesh, in contrast the MH mesh doesn't align at all, and therefore doesn't bend as nicely.
TPosePaints.jpg
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Re: MakeHuman NextGen Basemesh Talk

Postby bogdan666 » Fri Apr 26, 2019 5:23 pm

Thx for the explanations. Now I understand what's causing the bulge.
As for using the corrective smooth modifier as shape key in blender: it doesn't seem to work, if I hit "apply as shape key" and simply "applying" is not allowed with manually created shape keys.
Is there a workaround for this blender glitch (is this a glitch?)?
Another question: Whats the best arm pose for getting the best shape key possible in order to cover the full range of motion with one shape key or should I do multiple shape key for every arm?
Concerning the crease line at least it seams to be possible to achieve some decently looking transition between leg and torso by weight painting only, but daz is still better optimized and has a slightly higher resolution (looks cleaner). (will do some more weighting experiments).
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Re: MakeHuman NextGen Basemesh Talk

Postby polylearn » Sun Apr 28, 2019 7:50 pm

Hello, a newish user of MH and Blender here. Very impressed by how powerful this software is, but I also quickly recognized some shortcomings of the default MH models which might be best resolved by adding resolution to a few key areas of the base mesh.

For me the problem isn't so much any extra bulges but instead when I turn my yogini's arm behind her back, a narrow band of skin above the tricep gets twisted too tight. I do this mostly by local Y-axis rotation of upperarm02. Using upperarm01 and the shoulder bones alleviates the skin twisting but deforms the shoulder much worse.
https://gfycat.com/ElasticSpiffyCoati

Also, the shoulder-upper chest area moves in a slightly weird way, which is most noticable with the bikini strap on her right shoulder. The sides were posed individually so the animation is not fully symmetrical.
https://gfycat.com/CompassionateIllfatedArrowworm

Obviously these are made by manual posing without any Blender tricks. I only added some constraints to the arm bones to help keep rotations within natural limits. Rotation mode of all bones was changed to XYZ Euler. I don't know if that makes much difference but I had trouble with her arms glitching through the body when posing with WXYZ.

I suppose these issues could be worked around by modification of vertex weight groups as explained in the above posts, but really it would be good to have something done about the base models to make deformations more natural when just starting out.
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Re: MakeHuman NextGen Basemesh Talk

Postby bogdan666 » Sun May 05, 2019 12:30 pm

Sorry, didn't see your post until today.
Did you get rid of the armpit bulge only by weight painting with "preserve volume" checked or without "preserve volume", because it looks quite good.
I've not been able to remove the bulge only by weight painting.
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Re: MakeHuman NextGen Basemesh Talk

Postby polylearn » Mon May 06, 2019 9:15 pm

No, I did not do any weight painting at all and did not use "preserve volume" because I didn't even know about that option - I'm really just beginning to learn the basics of Blender :D

I found out why you get the huge armpit bulge though. I think you are turning the shoulder bones straight up by the local Z-axis only, with the elbow pointing straight back in the default pose. The MakeHuman rig actually follows natural anatomy quite well in this case. Try raising your arm straight up while keeping the elbow pointed straight back - I bet you cannot, this would break a bone. You have to rotate the elbow to the side maybe 60 degrees when you raise your arm. I did this with my animation, rotating the shoulder bones by the local Y-axis which contributes to the raising of the arms.

However, one thing I am now noticing is that the MH models do not have movement of shoulder blades. Apparently the clavicle bones don't have any weight paint for the scapula area on the back. This has a big impact on how natural it looks when moving the shoulders, there should be some movement along the upper and middle back and also further below the armpit, almost down to the waist.
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Re: MakeHuman NextGen Basemesh Talk

Postby bogdan666 » Thu May 09, 2019 5:50 pm

Without "preserve volume" checked most arm/shoulder poses look pretty good, but the knee joints and the hip/butt looks worse.
With preserving volume its the opposite: butt, knee and hip deform relatively well, but the arms/shoulder poses look worse.
But I still prefer the preserve volume option, because it's simpler to solve the shoulder/arm problem than the other body parts.
The solution would be as you say playing wit the the bone rotation, applying different weight painting, shape keys and last but not least a better proxy mesh (or higher resolution mesh-->"subsurf modifier").
Would you say, that the reference poses in blender (MHX2 Runtime panel--->poses (only visible in pose mode)), esp. the "benchmark", "fight02" and the "gym" poses are anatomically correct regarding the bone rotations?
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