Max8: Wrapping a chain mesh around an object.

Geezus

So I have this mesh:



I want to take this and wrap it around my character's arm. I'm having trouble finding the right modifier for this job. Most of what I've tried alters the mesh of each link in odd ways. So the chain isn't able to keep it's form. Anyone else ever run into this problem, or have a solution/tips for me? Thanks. :]

Rick Stirling

the simplest way - create a bone chain.

Make each bone the size of a link.

Weight each link 100% to the corresponding bone.

Wrap the bones around the model.

You could PROBABLY go as far as linking the bones to a cloth helper, using it to get the nice wrap.

Geezus

Yeah, that was my next step. Right now I'm toying around with using a Spline IK Solver. It's producing semi-ok results. If it doesn't work out as well as I'd like, I'll jump to the bone chain. Unfortunately I'm not sure how to use the cloth helper.
I guess I was looking for an easy way out of this, heh.

SouL

Depends on how sophisticated you want it to be. I did something similar at work and I manually moved each link. With it's pivot set to the center bottom (same position as if you were to move a real chain link in life).
Didn't bother weighting it if I could achieve the pivot point with a faster way. Each link was its own object and I grouped the entire chain together.

Don't get too caught up in trying to make the orientation of each link perfect. I didn't... and it works fine. There's a point where that stuff really doesn't matter.

low odor

path deform seems to work fine...just have to fiddle with it for a bit to get and acceptable result

MoP

Yeah, I was gonna suggest Path Deform. Although it might bend each link a little... unless maybe you did a clever thing with the spline and just added a few control points where there was bad deformation. Should be waaaaaay faster than bones and more accurate too.

Geezus

I tried the Path Deform, and I wasn't getting solid results with it. I ended up using a Spline IK Solver to pose it the best way possible, then killing that and tweaking each link manually.

Ultimately, part of the chain wraps around his forearm and hand, and turns into a spiked weapon of sorts. So, I'll need to revisit this in a few weeks to get this to animate properly. I'll probably have to end up setting up an IK chain for this. But, for posing purposes right now the SplineIK Solver did it's job. I appreciate the help. :]

Rob Galanakis

You could try turning each link into a rigid body, and arranging it via physics? Inside the Havok simulator, you can manipulate things around. I'm not very experience with 3ds physics so I'm not sure, but its definitely possible.

Mark Dygert

I think the splineIK solver was a good way to go. I'm not sure the design is the smartest, that could be a nightmare to animate the chain transitioning at the wrist... But sometimes we don't get to change the design and it sounds like you're stuck. This is one reason I like concept artists who know technical limitations.

Dreamer: I want 5 million hoses going from the back of the head to each finger and toe!
Modeler: I think we can get that done if the hoses run along the body.
Dreamer: HAHAHA good one, No. They are free floating and have a mind of their own acting like a shield sometimes. Oh and here is a giant vat of goo strapped to his back but it doesn't have a lid so it slops goo all over the place. The goo is acidic so it eats thru the hoses, but they grow back. Now get crackin' I have to put another coat of wax on my porsche before my lunch date with that porn star I'm dating.
Modeler: 1) She's a hooker, the same one you got me for my bachelor party. 2)Good luck with that... I'm going to find a place where the people don't eat rice cakes sprinkled with heavy metals.

umm-yeah where was I?


Apart from that you could have tried to use the spaghetti feature of the Advanced Painter Script to paint a spline that conforms perfectly to the surface of the arm, then use the path deform on it. I've done that to get roots and ropes to drape/grow on top of objects, works great. It saves you from having to try and line up a spine perfectly. Since it makes a spline you can always tweak it after you paint it to clean it up or smooth it out.

Reactor is a nightmare to use, I use it quite a bit actually and keep hoping it will get an overhaul. In this case you would pull your testicle hair out trying to get it to work. It would never wrap around the arm for you. It might drape over it like a limp noodle ok, but never wind around without crapping itself 20 times over.

Geezus

OoOOoo...that's sexy. I think I'll give that a try when I get back home. As far animating it transitioning at the wrist, I was thinking I'd keep the parts wrapped around the forearm/hand static, and only animate from where he has a grip on the chain to the end of it. Hopefully only a few testicle hairs will be lost. :]

Delaney King

You can also unfold a copy of your mesh, build the chain flat on that surface- skinwrap it onto the surface, then morph the model back into its original shape. This is better for doing all those complex straps and buckles, but works equally well with a chain.

MoP

Hmm, smart idea Dave, nice tip!

Sage

Another thing you can try is to use a bend or path deform WSM one since it gives better results. With the bend you can try and give it partial bends then tile the chain link to avoid deformation, instead of just making one piece wrap the entire 360.

Alex

hawken

in cinema 4d you would make one link, a spline, then clone the link as many times as you need along the spline with a 90 degree rotation per step. there must be something like this in max. Placing each link by hand is just mental.



(took about 1 minute)

MoP

Yeah, you could just make a spline then use the Spacing tool to achieve a similar effect in Max, to what Hawken shows.
Not sure if you can rotate every other mesh to 90 degrees (although you might be able to, I haven't checked), but it would be easy to just make 2 links at 90 degrees to each other and use Spacing on them individually with the same settings.

Archanex

I'd probably go with a path deform just for the ease of it, but if you did want to do it with cloth you could

SuperOstrich

You could use the spacing tool like MoP suggests, then after you've got all the links created, select every 2nd link (maybe in the Select by Name tool) and rotate them on a local axis/pivot point center 90 degrees. It would take care of the rotation all at once.

MoP

SuperOstrich - that's why I suggested making two and rotating the 2nd one 90 degrees... then you can use the Spacing tool with the same settings on both, and avoid having to manually select every other link afterwards and rotate them

hawken

[ QUOTE ]
You could use the spacing tool like MoP suggests, then after you've got all the links created, select every 2nd link (maybe in the Select by Name tool) and rotate them on a local axis/pivot point center 90 degrees. It would take care of the rotation all at once.

[/ QUOTE ]

that wouldn't really work, as the links should follow the direction of the path, as in the image above.

MoP

Hawken, the Spacing tool has an option to set an object's orientation to follow the spline direction... I wouldn't have suggested it if it didn't.

fritz

i smell kratos.

fritz

hey dave...is there any way you or someone could elaborate a little bit about the unfolding of a model?

Joseph Silverman

Sorry to bump this thread, but I wanted to second fritz's request -- I'm not sure quite what Dave means, but it sounds really useful. Anyone mind elaborating?

FatAssasin

You can "unfold" a mesh using a cloth simulator. I don't know if that's what he had in mind, but it's one way I can think of. Break the edges where you want the seams, then drop it on a plane using the cloth sim.

mookster

Im sure this is what Dave meant:



Hopefully Im not confusing anyone further
I didnt get good results until I made the chain closer to the surface, and set the falloff of the skin wrap to .001