I was just messing around in A:M...like you do- when I suddenly had an idea to apply Newton Dynamics to one of my TSM2 rigged models.

What I got was almost-acceptable rag-doll physics! (Nothing good enough to show yet)

Using the arms and legs in FK (forward kinematics) I was able to apply a dynamic constraint to the hands and feet to get each chain reacting freely.

I also needed to 'center' the geometry of the model, and then it's rig using the main BODY bone in 'N'(move) mode.

Now, whats missing is a FK spine and collision-detection for the arms and legs...they are passing thru the floor after contact.

Still some experimenting... has anyone else ever gone down this road in A:M?

THIS: http://www.youtube.com/watch?v=ohNqCb--aSs Is a good example of what rag-doll physics is...

That was very impressive

I remember trying that with characters using cloth

Very cool demo. Show us something in A:M when you've got it figured out.

Here's where I am with THAT... JohnL3D offered some ingenious information which involved turning your character into CLOTH and simulating... very good collision-detection and falling, but the downside being that your RIG is lost (so are your bones) so the character does not fall in a convincingly HUMAN manner, and he is in the Tpose the whole way...

Ideally, you would want your character to be animated...walking-tripping...etc... and hit a pose that would let the simulation take over. MY approach involved using Newton and dynamic constraints...but there were many drawbacks to that as well, chiefly collision-detection.

I haven't had chance to get back to this yet, so I polled the crowd to see if anyone had any brilliant ideas...like John's.

My 'dream' is to be able to set my character atop a precarios setting, like a staircase...and let her rip!

Couldn't you some how use one version on a "proxy" and some how transfer that motion to the character using constraints?

For example... there was a technique with cloth that constrained a bone to a spline so you could have buttons or things like that on the surface of the cloth simulation. Could you use the cloth physics and somehow transfer that motion from spots on a "proxy" cloth model to the appropriate bones in the rig?

-vern

...or cover yourself with mocap dots and throw yourself down the stairs! Easy!

That's thinkin'....!

But, typically bones drive the animation...this would be CP driven?

Yes. from what I remember it uses that "path" constraint thingy for a bone. Instead of traveling along a path it just stays in "one spot". I wish I could remember more. Entity did a demo at a MAAM meeting using this to put a bone controlling a mesh like a button, onto the surface of some cloth. It used the "path" motion from a spline of a cloth simulation. The movement of the path on a mesh is assigned to a bone using a path constraint? I hope I am remembering this correctly. It could be I've completely zoned out on this.

-vern

Here is my attempt to simulate ragdoll in A:M....

newton+dinamic

That's COOL Xtaz!

Did you use the collision-detection on the dynamic? I see there is a little trouble with 'pass-thru's'...Holmes gave us a little trick to try---- when you simulate... SIMULATE IN FRONT VIEW (2).

Isn't that the same as what someone used to show a guy getting shot, falling off a bridge, landing on a car and flopping around? I tried to search the forum, but I couldn't find it..

Yeah, that's a great test!

That test used BVH files exported from another program. It didn't use the AM physics. The BVH was imported to a rigged model. It works but you have to have access to another program. I like the "built in AM" approach myself.

-vern

That looks good Xtaz!

Michel

Oh..



Agreed.

Wow...those are some bouncy bodies...

Nice work - very promising.

I was that guy that did the BVH export approach. I like Xtaz's. I'll have to play more with Dynamics in AM. I like the AM approach as well, since it's all in one program.

Hi Xtaz,

That would give a nice Tut for your website, wouldn`t it?

I think I'm onto something.

Here's what I have so far:

I am using the Thom character for an AM promotional video that features dynamics. At one point he gets clobbered by a bunch of falling stuff that knocks him off a stool. I don't need anything fancy.

I created two spherical newton objects. These are what I'm calling "newton proxies". I have a smaller one for the chest hands and feet and elbows and knees. I use the larger one for the head and hips. Inside a choreography I then set up these proxies as newton fixed joints with "center parent" to each proxy in that location. For instance the hand is jointed with the elbow, the foot with the knee, the knee to the hip proxy etc. Creating a sort of "fake" body rig to control Thom. I then used a translate to for the hand, feet and hip nulls to the proxies that I placed in those locations. The proxies are roughly the shape and position of Thom's parts so there is "some" collision detection but this is mainly for the "motion".

My test is not "ready for prime time" and looks silly but it did what I expected which is a start. I'm having trouble deciding what to do with the head. I can't use a translate to constraint really. I could use an orient constraint. I probably need to have an "alternate" rig pose to change Thom's set up so I can switch it when I have the dynamics hit him. So I could make his head the end of an IK chain. Or I could use a dynamic constraint as you guys did. I also need to figure out how to keep the proxies from "spinning" around like crazy so I could use an orient constraint as well as the translate constraint.

I could see this getting me half way there with the dynamic "rag doll" physics motion and then cleaning it up.

-vern.

Yeah! That's a pretty good approach! You can always go in afterwards and animate the head yourself... it begs for experimentation...we'll have to get the tinkering gnome on it...GOOD THINKIN, VERN!

To quote Bill Murray in Ghostbusters... "I'm gonna have to take-back some of the mean things I said about you..."

Holy cow!

I think I'm on to something now... by accident. I never tried using a path constraint in an action before. There was another thread discussing a cable connected at both ends that has "physics" properties. Like two space ships tethered. So I did a model with a cloth mesh and a cable "tube" and used a path constraint for each bone of the cable to one of the splines of the cloth. Each constraints ease incremented. Worked like a charm:

http://www.hash.com/forums/index.php?s=&am...st&p=288987

So... this leads me to my next idea. Put a "proxy" cloth mesh inside a character model. This cloth mesh would be very low patch count and would be "designed" to match the characters main bones. Each control bone of the character would have a path constraint to the appropriate spline of the cloth and it's ease set. This could be done in a pose (can path constraints be done in a pose? Haven't tried yet but I'm sure it can).

Having it in a pose it could be used to "blend" with any other actions right? You could transition to the "rag doll phyisics" pose.

Will play with this next and let you know how it goes.

-vern

Cloth update:

Preliminary tests (ugly as heck) show this will work very well. However it will require a new rig... or an alternate rig pose. As was mentioned before the head and spine are an issue. They need to be like the arms and legs with an IK set up. I don't know a lot about rigging characters. I'm doing this with the Thom model which most likely has the 2001 rig? What I'm thinking is could this rag doll pose be a percentage pose? Couldn't you then transition from a normal rig set up to this "hit" or falling pose? Could a pose like that "blend" with other rigs already installed? Or would actions be a better way to go?

Another thing that might work which I have not tested. A separate cloth proxy model for Thom with some bones that match those in Thom. Constrain those bones in the cloth proxy to the Thom bones in an action (action object?) then in another action for Thom do the path constraints. So it would go like this: cloth thom action follows thom around. Stop that action switch to the Thom rag doll action. Cloth thom takes over and moves real thom. Switch back. I'm thinking even getting the rag doll stuff to "look okay" then bake those bones and tweak. Would prefer though it could all stay as actions or poses for easy use.

My brain hurts now. Taking a break. Best bet would be to stop trying to do this with a complex rigged figure and use very simple models to test all this out with first. I am very pleased with the early results but it's not near ready to show anything yet.

EDIT: Model penetrations are an issue since the cloth is so thin but I think assigning newton to the figure model might fix that. Even a static object will react to physics. The problem is will this effect the path constraints or visa versa? More testing of course.

-vern