[3DSMax] Pole Vector equivalent in Max?

Gungriffon Geona · Aug 2018

I've been working on building an IK setup for a game mesh so I can more easily animate it, but I'm having near constant problems with actually keeping the leg aligned forward in bends.

Image: https://i.gyazo.com/d3dc14f37eb5814874779fb57ac83193.png

In order to keep the joints moving as intended, I have the skeleton like this. However, an issue occurs with the IK in that it wants to bend inward if I pull the leg upward:

Image: https://i.gyazo.com/92ad720aec3a6728f6f71a236dbea052.png

So now I'm sort of stuck wondering how to fix this. attempting to remove a bone from the chain and have the hip joint causes the opposite angle issue- the bone rotates outward constantly. Freezing axis for this causes an issue where swivel is no longer possible. Frankly, i'm confused and don't know what I need to do. Someone mentioned that in Maya things like this can be fixed with a 'Pole Vector', and I was wondering if there's an equivalent in Max? or at the very least, ANY way to get this to stop happening?

poopipe · Aug 2018

In short you're doing it wrong.
The ik solvers in max work in a single plane so in this case youll never get a correct knee bend.
Run the controller from the thigh to the foot and for now, drop the extra knee joint(walk before you run)
If memory serves you can just link a swivel target into the controller from the motion panel.

If you're serious about rigging this it's worth looking for a decent tutorial on building a good rig. Most of the ik/fk blend rig walkthroughs will show you the fundamentals of setting this sort of thing up so it's easy to work with...

Gungriffon Geona · Aug 2018

There isn't an easy way to make this joint work straight down. It's an inherent issue with the design. Moreover, the extra knee joint is not an issue, it was the easiest thing to solve in the whole chain by just limiting angles. I solved that in seconds.

Image: https://i.gyazo.com/c3e63b4c04f57083febf5d870eba4d07.png

the balljoint is where my issues lie. having outside the IK defeats the purpose of having an IK solution driving this at all, because this happens. you would have to manually control the balljoint at all times.

I have been following the 3DSmax Knowledge Center tutorials on creating a skeleton from scratch (because CAT Studio has proven time and a again that it doesn't want to play nice with anything mechanical) but nothing ever assumes how to handle different character setups than 'leg goes straight down'.

poopipe · Aug 2018

The hip/ball joint is basically the same as a clavicle.
Conventionally you would rig it to move automatically as a reaction to what the arm is doing.

Attempting to include it in the same IK chain as the leg shifts the plane that the IK works in away from the plane that the knee joint needs to bend. The knee of the IK chain is then effectively floating halfway between the top of the ball joint and the ankle so the leg isn't guaranteed to bend straight and if you do add a swivel target it will behave oddly.

You can probably force it to work like this but it won't be robust.

Gungriffon Geona · Aug 2018

Alright, I didn't know that. Is there any tutorials that you recommend that talk about how to do that? The Knowledge Center tutorials don't talk about clavicle motion blending at all.

poopipe · Aug 2018

I bought a really good one about 8-9 years ago but that seems to have disappeared.

This seems to cover most of the basics. although they don't cover auto clavicle rotation, it does explain ik/fk blending so you'll get an idea of how to weight multiple constraints against each other - which is what you need to do.

https://area.autodesk.com/tutorials/series/character-rigging-in-3ds-max

This is an auto clavicle setup

https://youtu.be/xf71AlH-9TA

There's other ways to do it but it's a simple and elegant enough solution

musashidan · Aug 2018

poopipe said:

I bought a really good one about 8-9 years ago but that seems to have disappeared.

Was that the Paul Neale(Pen) series from CG Academy? Pretty much the definitive Max rigging go to.

CG Academy went bang as the owner ran with content creators' money, but if you contact Pen directly he might be able to help you out.

poopipe · Aug 2018

It was narrated by a guy from somewhere in eastern europe I can't be any more specific unfortunately and I imagine the business has gone the way of everything else based around max and animation since the balls-up they made of the curve editor after max2009.

Paul Neale is a very good shout - he's clever

Gungriffon Geona · Aug 2018

https://www.youtube.com/watch?v=Pby-a0xHL9s

I managed to solve it. the Orientation constraint worked in place of Look At and did the exact job I needed from it. I've since added a swivel control and fine tuned it since making that video, but I've got it all set up nicely now, even if I don't have the ability to manually change the hip angle to create some jostle movements to make steps look heavy. I can deal without it though, there are other ways to do that.

[3DSMax] Pole Vector equivalent in Max?

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