Hi there,
Just wondering if anyone has tried to make a soft IK setup like this? I used this ages ago in Soft and loved it. I basically lengthens the bones a little to remove that pop you get when an ik chain stretches right out.
I'm just getting into rigging in Houdini so I don't like my chances but I might have a crack at it…
http://www.andynicholas.com/?p=88 [andynicholas.com]
Thanks,
Pete
Has anyone tried to make a soft ik solution?
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Werner ZiemerinkIt *is* built in.
Really nice to avoid elbow and knee snapping. This together with stretchy bones should be built in by default.
Please submit a RFE
As for stretchy bones, they're built in as well (sort of). It's not a one checkbox solution, but easily done with an expression (or CHOPs). The length of the bones can be modified on the fly.
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Oh? In Softimage I can lengthen a bone to which there's a mesh “skinned” without problems (not that any Softimage rigger worth his salt will use actual bones for skinning), no need for expressions (other than those for the stretch). What should one exactly do in Houdini regarding the capture to a stretchy bone?
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there a few ways to do a stretchy bone
if you drop down either the simplefemale or simplemale assets on the Character Tab you can see how we've do it for these simple example characters…
for the bone length parameter we do this:
{
vector wristPos = vtorigin(“../ctrl_clavicle_left”, “../ctrl_IK_wrist_left”);
float distance = vlength(wristPos);
float stretch = distance/0.405077;
float length = 0.215;
if (stretch >1 && ch(“../enableSnS”)!=0){
length *= stretch;
}
return length;
}
basically…
check to see if stretch is enabled for the character
if it is, multiply the bone length by the stretch amount - which is found by comparing the current distance between the shoulder and the IK goal and the default amount…
you don't have to do anything with the region if you just want stretch - if you want squash you'll need to play with the deform regions (3rd tab on the bone object)
if you drop down either the simplefemale or simplemale assets on the Character Tab you can see how we've do it for these simple example characters…
for the bone length parameter we do this:
{
vector wristPos = vtorigin(“../ctrl_clavicle_left”, “../ctrl_IK_wrist_left”);
float distance = vlength(wristPos);
float stretch = distance/0.405077;
float length = 0.215;
if (stretch >1 && ch(“../enableSnS”)!=0){
length *= stretch;
}
return length;
}
basically…
check to see if stretch is enabled for the character
if it is, multiply the bone length by the stretch amount - which is found by comparing the current distance between the shoulder and the IK goal and the default amount…
you don't have to do anything with the region if you just want stretch - if you want squash you'll need to play with the deform regions (3rd tab on the bone object)
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arctorsadly you do,
…
you don't have to do anything with the region if you just want stretch…
to get correct deformation you have to scale both deformtopcapz and deformbotcapz by the same stretch ratio as you scale the bone length (compared to rest or captposelen )
Tomas Slancik
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Method Studios, NY
FX Supervisor
Method Studios, NY
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tamtearctorsadly you do,
…
you don't have to do anything with the region if you just want stretch…
to get correct deformation you have to scale both deformtopcapz and deformbotcapz by the same stretch ratio as you scale the bone length (compared to rest or captposelen )
sure…
I don't automatically assume that stretch includes volume preservation
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tamteWe get quite good results with just scaling the bone lengths when it comes to stretchy toon rigs.arctorsadly you do,
…
you don't have to do anything with the region if you just want stretch…
to get correct deformation you have to scale both deformtopcapz and deformbotcapz by the same stretch ratio as you scale the bone length (compared to rest or captposelen )
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digitallysane
We get quite good results with just scaling the bone lengths when it comes to stretchy toon rigs.
would like to see that, maybe I'm missing something
here is file with default results I'm getting with changing the lengths of the bone and after compensating deformation caps as mentioned, which I found to be necessary for good results
Tomas Slancik
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Method Studios, NY
FX Supervisor
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