Hi guys,
So I’ve started looking at the crab rig, just replicating the loco at the moment from the recent showcase.
I’ve tried for the life of me to replicate it, but having issues. (I’ve tried several times)
I’m following all steps to pin the chars body and legs, setting the T Stiffness to 12 and R Stiffness to 1 (like in the tut/ Ive also tried with the R stiffness at 0)
Im getting different results my end, the claws really don’t want to change their shape, so they aren’t being pulled to the pin as well as they do in your tut… even ranking up the T stiffness to the 100s still doesn’t work?
Next issue is when I assign a plan, the walk itself doesn’t look the same, again down to the limbs not following the pins that well when set to T12 R1.
Any help would be appreciated… I’ve tried several times using both v5 and v6 crabs on two machines, so I’m sure im missing something… most likely something very obvious lol?
Hey @taylorkevin, welcome to the forums 
One of the things we changed in the crab from the version in the livestream was the feet; they were almost entirely extended in the original rig, which was why Jason went ahead and moved the pins towards the center before assigning a plan, to give them some slack. That should no longer be necessary, and I think in your case the feet positions aren’t leaving enough room for the legs to comfortably walk.
But that doesn’t explain why they aren’t following the pins though. 
What if you assign just a single pin onto the tip of one claw, and lift it up? Are you able to have it follow the pin closely? What about both claws? And work your way from there, until you start noticing that they don’t follow anymore.
Hi Marcus, thanks for getting back to me.
Sooo, I’ve just tested again and I think I’ve found the solution… If i crank up the Tstiffness to much
higher numbers 1000’s, then it eventually pulls the claws much better (which makes sense, I just thought 12 was a stable amount) So I applied the same values to the feet too, though they dont need it quite as high as the claws, but they follow much more closely… does this seem like the best solution?
Thanks again
Oh, actually, you are right. This is correct, but it is also not what I expected.
The reason it needs such high values is because these tip markers are incredibly tiny. They weigh next to nothing, and the crab is being held up by it entirely.
It is not ideal, and now I also realise why this crab character needs higher solver substeps than normal, which comes at a performance cost. Ideally, we would attach pins to the last joint of the foot and move the pivot to the tip, the pins cannot have their pivots moved. Yet. And so that’s why we made this tip-marker, to give the tip a pinnable pivot.
It should work fine though and you can continue animating like this.
As an alternative, and I will investigate whether we can make this the new default, you can:
- Select each tip
- Set
Density = Off
- Set a
Mass = 0.01
And now they will have a comparable weight to the other parts of the leg, which will make stiffness values behave more predictably. That is, a value of 12 is high.
Ok I’m getting somewhere… I think.
Changing the density OFF, mass to 0.01, the pins are alot more reactive for me on 12 globally 
But, the claws are still requiring alot to pull them to the pin as shown below, approx 500 T stiffness.
What I’m seeing is the upper part of the claw seems very stiff, which is actually pulling the whole body over to the pin. crabRig_v006_publish:control46, I’ve tried lowering the stiffness on that group and on the marker, but it doesnt help… So maybe it isnt that, but visually it is 
Other things Ive checked:
- Scene:cm
- Xref and directly in the rig file
- Tested on two different machines
Things against me:
It’s a Friday afternoon 