Making of female with ziva

mikeporetti

Hey guys!

Here is what i have so far. Im using as reference anatomy books as well as the ziva promo videos, freeze framing the videos to get a look at how they did it.

image back.png

image front.png

Im curious how everyone is handling attatchments. I was using all fixed attatchments to connect bones to muscles. However I was getting some trouble areas as shown below:

image fixed.png

However I changed some of the attachments to "sliding" and got way better results. As shown below:
image sliding.png

So my quesiton is: what is considered best practices when it comes to some of these attatchment points?

When would one use fixed vs sliding? Will using sliding attachments in my biceps give me any issues on a more serious animation?

Cheers,

Mike

mikeporetti

Having an issue in the shoulder area, where it becomes a bit of a mess. any tips on how to keep this area clean, not penetrating and deforming nicely?

Heres my setup in tpose:

image shoulder-tpose.png

Here is the result when i raise the arm in front of the char:

image shoulder-crushed.png

view from above:

image view-from-above.png

andy_vs

Hey Mike --

You've been busy!

Would be good to see more of the ziva side of your setup. It would be easier for me to get a feel for your system if I could see:

How big the tets of your tissues are
How many attachments overall you're using
What fibers if any you're using

As for best practice with attachments. A good rule is to use small attachments at the origin / insertion points at the ends of your muscles. By small attachments I mean small groups of vertices. Do a broad strokes setup where you only do origin / insertions.
Play back the scene with some basic animation on the character -- maybe he's going through some basic shoulder poses or something. From there you'll be able to see how your muscles are performing and gauge what you need to do from there.
In general with attachments, you want to be as sparing as possible. Using too many attachments will result in your system being over constrained and won't give you the nice organic results you want.

Use fixed attachments to attach muscles to bones at origin/insertions. Use sliding between muscles or between muscles and bone when you want to preserve the distance between bodies but allow them to slide tangentially.

Looking forward to seeing more!

mikeporetti

Progress update:

A few questions:

Any tips on the latisimus dorsi? It wobbles around alot, should i attatch a large portion of the sheet muscle to the ribcage?

What is prefered method for abs? Ive seen two pretty successful examples here

Chenchen

mikeporetti Hi, the first sim is nCloth. I just wanna use it to test zCloth. 🙂

andy_vs

Hey Mike, nice progress.

Just looking at your skeleton there and noticed the hips and femur bones are bending. I know you're focusing on the upper body -- just wanted to check the bones in the upper body are moving as rigid objects, rather than bending.

Could be wrong but it also looks like your scapulae aren't moving.

As for the lats, try putting a zFiber on there. Paint the end points so that the insertion onto the humerus is black and the vertices that run along the spine are white (or vice versa). At the start of your animation, set two keys on the excitation attribute. 0.0 at the start frame and 5 frames later, key it to 0.3. You should see the lat contract over those frames and you'll have tension in the muscle over the course of your animation.

The reason to key it, rather than just set it, is so that the muscle doesn't jump abruptly on the first frame. This will give the collisions a better chance to resolve.
You can still use zLineOfAction to do additional contraction for different poses.

I'll let Lonnie comment on the abs 😉

mikeporetti

Hey andy thanks for the advice, my reply is late but I went and addressed the issues you mentioned right away.

I have yet to keyframe excitation yet, however i was thinking it would be cool if on the zLineofAction node could take care of preroll somehow.

Also does anyone have any good tips for fixing penetrations as fast as possible? It would be great to have a tool that pushed verts apart in a way that maintains a smoothish shape.

heres an update:

Here is an update.

andy_vs

Hey Mike
Nice results!

First thing I noticed was the sternomastoids on the neck are bending quite a bit. Those lines should be fairly straight through the different poses. Looks like the tet resolution is a little low and/or you might have attached too far down the muscle to the bones. These muscles will also benefit from the constant excitation I mentioned earlier.

For your penetration issue, I haven't tried this exactly, but you could experiment with turning all the muscle geometry objects into tissues, with a fairly high tet resolution. Make the bone geometry into ziva bones. Turn damping on the solver up. Turn collisions on. The solver will try to resolve the collisions on the first frame of the simulation. With a higher damping value they might stay in pretty much the same place. Worth a shot?

Can you explain how you'd want to see the line of action help with run up?

How does it the sim look from the back?

mikeporetti

hey thanks andy, I misinterpreted stretch bias docmentation at the time of that video. Here is a more recent simulation with back and side view. Im still learning how the LOA works so i will hold off on recomending anything.

Still getting some penetrations even on muscles that start without them. Can people share their production settings with me? I am currently using tet size of 1 and 2 solver samples.

Wavelength

mikeporetti oh thats unfortunate. thank you jamesj

mikeporetti

two penetrations I have seen:

bottom of scapula penetrating thru latissimus (when she pulls her arms back)
top of the illiotibial tract ( point between gluteus maximus medius, fasica ) (when she squats down)

mikeporetti

wip. ziva cloth definately solves much better for this stuff. Very impressive. Still lots of issues tho, I think my line of action pos sensitivity is too high.

andy_vs

mikeporetti

Hey mike, nice update.
Those quads look like the should jiggle a bit more. They're pretty meaty, yet don't have a lot secondary. I agree about the pos sensitivity -- looks like the flexing hits quite suddenly. Pretty clean cloth sim though!

mikeporetti

Thanks andy.

Ive attempted a couple of fat simulations. Here is my model

image fat.jpeg

When people create the human form in zbrush they create it as it is, with gravity affecting all the soft tissues. You might say the gravity is "baked in" from a simulation perspective. However if you simply convert a fat layer to a ztissue and attatch it to a bone, gravity begins to take its toll... AGAIN. Its a doubling up of gravity. Is there a solution to this? My current Idea is to resculpt my body and remove all trace of gravity!!

What would be nice is for the simulation to run and store simulation data on the vertices, save that information and then somehow apply that information back on the sculpt (at frame 0) without applying the deformation. another way to think of it would be a kind of "maintain offset" per vertex

andy_vs

mikeporetti

Hey Mike,
One strategy is to negate the effects of gravity in bind pose. What you could try, is taking your current setup and reversing gravity. (so multiply the value on the solver by -1) Then solve a few frames, let the sim settle, stop the solve, and duplicate off the geometry.

Use zBuilder to recreate the setup on the duplicate. That becomes your new asset. (solve gravity as normal on your new asset)

Would be interesting to see how you go with this approach!

Cheers,
Andy

mikeporetti

Hey andy, I tried doing what you suggested, however i couldnt get it to look good. I decided to just keep sculpting a shape and running the sim over and over untill i got something reasonable. Here is what i have so far:

andy_vs

Hey -- awesome stuff!

Wondering what settings you have for your fat solve. I would suggest you run 4 substeps, and turn any damping right down so you can capture the full secondary motion from your animation. (1 substep for instance will have the effect of "damping" your results) The jiggle frequency for fat is pretty high; would be cool to see a little more in your sim.

Some very cool stuff happening here though. Are you planning on running other animations?

mslib

This is looking really good. I just saw the latest video with updated jiggle settings and it is coming together nicely. The only thing that was sticking out to me was the pelvic bone area was shearing.

Even though your fascia is wrinkling/shearing oddly in some areas your outer skin is looking quite stable. Are you running a tissue sim after the the cloth sim?

The subtle form changes in the upper back are quite convincing, and your process for sculpting the breast tissue without gravity turned out well.

mikeporetti

Andy Thanks so much for that info, I had it on 1 substep. Noob mistake. Here is a render after i made the change.

Also I switched the fascia connection from fixed to sliding which is shown in the renders fat sim but incidently i didnt update the fascia for this particular render.

Id love to do more animations but im not an experienced animator and what you see here I had spent more time than i wanted doing, using tutorials. I wanted this sort of runway walk and i couldnt find any mocap

mslib, im not sure what you mean but my steps are:

muscle sim (using zbone and ztissue)
fascia sim(using cloth)
fat sim(using zbone and ztissue)

someone should put NSFW in my thread title, im not sure how to do that...

mikeporetti

do people usually use a skinwrap to drive the render geo from the fat mesh?

andy_vs

Oh wow, way more motion! Nice!
Would be cool to see your new fascia, and also what the sim looks like from the back.

To get back to the skin, one way is to have a separate file that takes:
- An alembic of the fat bake
- An alembic of the skinClustered render geo from original anim (for head, hands and feet)

Then just wrap a copy of the render geo to the fat.
Make a blendshape between that and the skincluster alembic and paint the weights of the blendshape to blend the two meshes together.