Motion Capture (bvh) tuts and info?

[rusty]

Hello,

 

Years ago I played with using bvh MoCap files with AM and various rigs. I also purchased the entire Truebones collection and started indexing the files.

 

I'm looking into bvh MoCap w/AM again and wondered if there were any tuts or other information on the subject.

 

I remember stumbling onto a way to scale each part of a bvh mocap rig to the model rig and also got whole mocap thing working pretty well (though I didn't document any of this...DUMB!). So I want to research it all and try it again. If I get it all working again and find that none of the current AM/BVH MoCap tuts cover any of my own methods/discoveries I'll add a tut to demonstrate these.

 

So, if you are aware of any tuts/info on this, can you let me know?

 

Thanks!

Rusty

 

 

[Fuchur]

on my website there is a simple video tutorial on the subject. i am not aware about more tutorials in that direction.

 

see u

*fuchur*

[Rodney]

In addition to Fuchur's tutorial...

 

Somewhere out there, Will Sutton has a video tutorial on connecting a rig to BVH.

[rusty]

I have two tutorials on A:M/BVH mocap...one is Fuchur's and one is a text file, source/author unknown. I'll google William's tut.

 

Thanks for the info!

 

Rusty

[John Bigboote]

BVH in animation Master is rather simple:

 

-get yourself some BVH files to work with.

-Make a new action for your rigged character. I like to make sure my characters arms and legs are in full FK.

-Make sure you are in Animate mode for the loading of the BVH.(red 'A' in top toolbar.)

-Right Click on the action and select New/Motion Capture/ Biovision BVH

-Select a BVH file from your HD. You will see it loading. You will then see a 'bones' character in your action, and you can scrub to view the action-make sure it is a workable file.

-Scale the BVH to relative size of your character, you can rotate the BVH to face the same direction as well.

-Starting at the feet working upwards- apply 'Orient Like' and 'Translate To' constraints to each foot, the hips and chest, then the hands. 'Aim At' constraints can also be used, like for the upper legs- aim at knees... You will need to set the offsets for the bones as well... usually zero-out the values in the constraints offset X,Y,Zs. Do not worry about individual fingers, face, or toes info unless it is in the file and you want to.

Once done... hit play and watch your character move with motion-captured nuances! Most BVH capture files have trouble with 'flipping hands' or 'feet thru floor' or 'jump frames'... you can correct these as you see them in the action by keyframing correction or deleting bad keyframes from the BVH. Many BVH files are captured during a 'session' and share similar orientation attributes, you can easily import a new BVH from a like session without the need for re-constraining everything.

 

HERE is something I worked on for Mr.Bones recently- showcasing his actions on my character with A:M's dynamic hair. BVH's are fun and can be mixed with custom animation. Hope this helps!

 

[Fuchur]

I really like the hair you've got there... the movement of it looks very naturally.

 

See you

*Fuchur*

 

PS: Not that I wouldn't like any other movement in the scene...

[John Bigboote]

Thanks Gerald- been working on it... it is okay- could be better. At least it is not 'jumpy-aroundy' and I am getting pretty good collision-detection out of it nowadays... it does stretch a bit tho under extreme dynamics.

[fae_alba]

wait...there was hair???

[rusty]

Thanks for the instructions for mocap which I'll go through! Maybe 6 years ago I had all this aced...my only problem now is remembering the constraints needed with the old Anzovin TSM2 rig.

 

Cheers,

Rusty

[John Bigboote]

That model (animation above link) is rigged via the TSM2 rig... ONLY constraints used in the action are:

 

-Orient Like

-Translate To

-Aim At

 

I've been thinking about a possible feature request, a NEW constraint that essentially would be an 'orient like' and 'constrain to' combined... specifically for BVH's.

[John Bigboote]

Here is a screenshot with all of the constraints I used on my Outsquirts character... 19 in all(sometimes I'll use a 'Translate to' on the head as well- in this case it was causing some sudden subtle yet jerky motion which would cause the dynamic hair to 'fluff-out'...) In the image I show how I animate the offsets of the constraints. EDIT: I see in this instance I did NOT use any 'aim-at' constraints other than the eyeball bones to their aimer null.

[rusty]

How awesome is this!!!!!!!!!!!!! Thanks John!!!!!!!!

[rusty]

John,

 

Did you adjust any of the TSM IK/FK poses?

 

Thanks!

Rusty

[John Bigboote]

Hey Rusty- THANKS!

Typically- when I am 'straight ahead' animating, I will put the TSM's arms into an IK setup, so I just need to grab the hand and the arm will follow and I can adjust the angle of the elbow afterwards if it looks weird... when I use BVH's however- I prefer to leave the arms in full FK... for some reason (as you can see in the video) I struggle with upper arms and shoulders the most... I don't know if it is me, the rig, the BVH(some are better than others) or just the whole process in general.

 

Using FK lets you put TT and OL constraints on each limb of the arm... which can be 4 in all... shoulder, upper arm, lower arm, hand. When you think about it, the human shoulder is quite a work of engineering(nice work, God!) it is a rolling, swiveling, ball joint underneath folds of musculature able to angle and bend quite pliably. The hips, in contrast, are also ball-in-socket joints but are locked-in-place and have a lesser range of motion.

[Roger]

Anyone out there using Truebones on a regular basis? Just wonder how viable this is for roughing in animation, or finished product.

[John Bigboote]

BVH is what it is... when it first became a viable animation form- and we could do it in A:M- I thought it was a real 'game changer'... meaning it would be the future of animation and would become more and more commonplace. It has not really done that... there is still 2 distinguishable animation methods, traditional animation where a person draws or generates motion into a drawing or 3D rigged character- and motion capture where a person's actions are captured and transferred onto a CGI character. It is great to know how to implement motion-capture into your character, but I think it is a greater skill to be able to straight-out animate your character as needed... adding emphasis, weight, squash-stretch, and character to the actions. Truebones is a great collection of motions, well prepared and sorted... but in real-life you will have a script or a need for a particular action, and finding JUST what you need in a robust library of motions can be akin to winning the lottery while finding a needle in a haystack.

 

BVH is great for gamers... they need particular actions that are simple... "walk, run, stand still, shoot weapon, die(zzzzz)". Storytellers will need something more particular.... 'water flowers on ground level- stand up and stretch achy back, take 3 steps to left around floor object, put water can on top shelf, sit down in chair and cross legs while grabbing glass off table...'

[Roger]

Yeah, I kind of assumed this would not lend itself well to telling a story but might work for storyboarding or doing something on a tight deadline.

[zandoriastudios]

here is the link to my mocap tutorial:

https://zandoria.wordpress.com/tutorials/am-mocap-tutorial/

[rusty]

John sums it up. It's just another tool. I bought all of the truebone's Mocap files a number of years ago. When I have a scene I search for what I'll need and try it out. I spent many years learning how to do character animation and I'm fairly good at it but sometimes you can natural motion our of mocap files that would be better then anything I could pull off. Tweaking is the name of the game in animation anyway...you always have to tweak the body motion and cloth you can only rough in--when the motion is done there's always CPs to adjust.

 

Rusty.

[John Bigboote]

Another MoCap promo by Mr. Bones (Joe McPeek)

https://youtu.be/BdR5byYz3xw

 

I notice in his that the hands don't really bend too much... which is interesting because I was having trouble with his mocaps with the hands changing orientation(flipping) and thought it was me... another thing to remember with A:M's 'Orient Like' constraint is that you can set a percentage value from 0-100%... same with Translate To...

[rusty]

Awesome advise! I have to re-read what you said about IK/FK...look at the related TMS poses...figure out how to set them...it's been years.

 

Babysitting our new grandson plus redoing the first draft of book of my long overdue sci-fi book #2 has priority right now.

 

Right off the bat I see you are applying constraints on bones that are by default not visible. Maybe the IK/FK poses will make them visible or maybe I'll have to do it manually.

 

Thanks!

Rusty

[John Bigboote]

Yes, either dig thru the model and make them visible(and later, invisible again...) or just know their name(s) and select them from the target list when applying the constraint.

[rusty]

John,

 

Now I'm confused. Can you please check and tell me if you leave all the sliders in the default (zero percentage as shown) position?

 

Thanks!

Rusty

 

[John Bigboote]

Well, this is 'personal-preference' territory... I will leave all settings at default, altho I like to put the 3rd one '1 right/left arm regular FK' at 100%... mileage may vary.

[rusty]

Thanks!

[rusty]

John,

 

Yet another question...in the image of the constrains you use for mocap, some bones are not expanded to show what the constraint(s) are used and what the target is. For instance the first bone, 1 left hand attacher and further down, 1 left lower arm, 1 right foot ik tagger and so on. Were these for something else or, are they needed in the mocap setup? If the latter, is there anyway you can get me info on these?

 

Thanks so much for your help!

Rusty

 

[John Bigboote]

I beleive I had expanded every bone that had a constraint... so if bones in that image have an arrow, there is no constraint there. The bones just appear in the list when I open it... I did not do anything to them at all.

[rusty]

Arrow? They are proceeded by a '+' which means it can be expanded which means it contains something. No worries. I can work my way through it.

 

Thanks!

Rusty