CAT Foot Platform Pivot

[stuart.butler]

Hi All,

I'm working on a rig suitable for teaching students to animate walk cycles. In previous years the first time they do this is using Biped and they are shown the ability to modify the pivot position of the foot to allow the weight shift from heel to toe to be constrained by IK.

I've looked for this ability with CAT and came across this article:

http://docs.autodesk.com/3DSMAX/16/ENU/3ds-Max-Help/index.html?url=files/GUID-B39C0590-058C-4E59-B03...

However, my foot platforms do not have a subobject. My foot does but it is the ankle pivot position and has no effect with regards to the need for a planted IK position to move.

Can anyone advise if this feature has been removed or if i need to activate it somehow.

I'm currenlty in Max 2014.

[Steve_Curley]

Help link is wrong - it points to the Basics section > Viewport Controls. Go back to the correct page, at the very top is a "breadcrumb" - a set of links to the page you are on, much like the one at the top of this page pointing to this thread. Grab a screenshot of the top of the page and post it, otherwise we don't know which page you're on. For example:-

[stuart.butler]

Ah, this link should work better:

http://docs.autodesk.com/3DSMAX/16/ENU/3ds-Max-Help/files/GUID-9E3DEE1E-D612-4B0B-BA57-1BFB2A73E6B3....

[Steve_Curley]

Seems the IK Helper is too small - the foot is obscuring it. If you follow the instructions then once you select SubObject (at the top of the Motion Panel) then the Helper is actually selected so move it as directed. You could select both feet (not the platforms, the feet themselves) and press Alt+X to make them see-thru. Then you'll be able to see the IK helpers.

As this is a CAT specific thread I've moved it to the CAT forum.

[stuart.butler]

The problem is that the sub-object doesn't exist when the foot platform is selected, so I can't select the pivot in order to move it.

[Steve_Curley]

According to your screenshot you haven't selected SubObjects - it's at the top, just above where you have "Parameters" selected.

[stuart.butler]

It isn't selectable, its blacked out. With objects which have a sub-object it has grey text and the selectable sub-object is faded in the dropdown.

Here is an example when the foot object is selected as it has an ankle pivot position.

[Steve_Curley]

Ok, create a new CAT Parent, apply a normal human character and follow the procedure on the help page exactly. I did that yesterday and it worked perfectly, allowing me to move the IK helper to the front of the foot then rotate the foot with the pivot now at the front, which is what you're after.
Having done that to prove it works, take a close look at your own rig to see what is different.

[stuart.butler]

I have the same issue with the Base Human.

[Steve_Curley · Accepted solution]

Because you're not following the instructions on the help page.
1) Add or highlight an animation layer and activate Animation mode.
Do that and the SubObject button will become available when you select the foot platform.

[stuart.butler]

Ah there we go, was my own madness, why i wasn't turning the animation mode on i have no idea.

Thanks for your patience and you help.

[Steve_Curley · Accepted solution]

Glad it's all sorted - I was running out of ideas 😉

[ankin.sergey]

Is there a way to move the pivot using the script? I wish to make it a bit easier for the animator by letting him move the pivot to the front/back/side parts of the platform in a single click on corresponding helpers added and linked to the platform:

--selecting my new helper on the heel

currObj = $

--it is already linked to foot platform so selecting the platform
max select parent

--turning on sub-object level

subObjectLevel = 1

--but neither this string:

$.pivot = currObj.pos

--nor the following

$.pos = currObj.pos

--are working

subObjectLevel = 0

It moves the platform like if "Sub-object" selection level would be turned off however it is on (can be checked when commenting of the last string). It looks like there is some additional Point object connected with the platform which can only be controlled via CAT. Please advice

[ankin.sergey]

I spent some time trying to add some script into this but I realized the problem is this is NOT working if you want to move pivot forward and backward during the animation. I am using Max 2015 so I need to ensure there is a reason to switch to a newer version. So could you please repeat following steps and approve all works fine:

1. Turn auto key on

2. Go into sub-object level as descibed in that link and move the pivot to the heel on frame 1

3. Put a key for platform at the same frame

4. Rotate it on frame 5 say 90 degrees (it should be rotated fine across the heel)

5. Move to frame 10

6. Go into sub-object level and move the pivot to the toe

7. Put a key for platform

8. At frame 15 rotate the platform accross the foe

9. Go back and ensure nothing was broken since frame 1

Thank you!