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kangddan

C4D IK/FW SWITCH TUTORIAL

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03:15s There is a bug

The video may be a bit faster, hopefully won't affect

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I'm not sure what this is for.  It seems it does the same thing as if under the IK tag under Advanced > Keep Goal, constrain Goal, Update On Goal, Align goal, and Update IK on FK were turned on and the IK tag was kept in IK mode.  With those on you can pick the IK goal move it around then pick a joints and rotate them just like if it was in FK mode without having to press any button.

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3 hours ago, Fastbee said:

I'm not sure what this is for.  It seems it does the same thing as if under the IK tag under Advanced > Keep Goal, constrain Goal, Update On Goal, Align goal, and Update IK on FK were turned on and the IK tag was kept in IK mode.  With those on you can pick the IK goal move it around then pick a joints and rotate them just like if it was in FK mode without having to press any button.

The Reset IK button in  IK settings does the same thing but only works within the IK settings so you can't reference this button in expreso.  You need to have Keep Goal on in the advanced tab.  Also to get it to work on rigs that have controllers you need to have the IK chain on the controllers.  If that button would be refferenced within Expresso it would make many things easier, but you cant even access it by any means other than from the IK tag, not too helpfull if you tags are within a complex hidden rig.

 

Dan

IK-FK Switch.c4d

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11 hours ago, Rectro said:

Also to get it to work on rigs that have controllers you need to have the IK chain on the controllers.  If that button would be refferenced within Expresso it would make many things easier, but you cant even access it by any means other than from the IK tag, not too helpfull if you tags are within a complex hidden rig.

I was thinking what specific rigging situation would the auto switching on the rig below not do the job.

 

With this rig you click on the box to move the IK and click a bone to move it in FK.  No other buttons or switches needed.

ik fk auto switch.zip

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I remember when it could first do that sort of behavior.  The behavior is kinda good kinda weird. I will maybe try to use it sometime and see what i'm liking or disliking.

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On 9/25/2018 at 7:32 PM, Fastbee said:

I'm not sure what this is for.  It seems it does the same thing as if under the IK tag under Advanced > Keep Goal, constrain Goal, Update On Goal, Align goal, and Update IK on FK were turned on and the IK tag was kept in IK mode.  With those on you can pick the IK goal move it around then pick a joints and rotate them just like if it was in FK mode without having to press any button.

There are a lot of restrictions on doing this. You can make a complete arm to verify that your approach is feasible. Many settings have to go through a lot of work to prove right or wrong.
You can use your way to create animation IK-FK-IK to loop, whether it works.

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9 hours ago, Fastbee said:

I was thinking what specific rigging situation would the auto switching on the rig below not do the job.

 

With this rig you click on the box to move the IK and click a bone to move it in FK.  No other buttons or switches needed.

ik fk auto switch.zip

Once you add the IK chain the rig becomes just that, a IK rig, you cant select the bones unless you move to FK within the IK tag slider.  Now the IK-FK slider can be used within a expresso for creating a driver control using user data, the key point here is the controls are easily accessible to the animator.  The issue here is two things.  At times you may want to use the IK to position the hand, then switch to FK to take over from that IK position.  By default the IK to FK slider does not work like this, its not a switch its a blend which means when you slide to FK you loose the IK position.  The only way is to use the Reset FK button within the IK tag, but this button can only be accesable via the IK tag so cant be rooted to be part of user data.  The second problem is, or at least makes it a bit more complex is you dont ever select bones of a proper rig, you select controlers that rotate the bones.  To do this you give priority to the controllers via constraints and now the IK tags reset FK no longer works as it only works on the bones, not the controllers.  This then leads to putting the IK on the controllers as in my file.

 

Out of this the issue remains, to switch, not blend between IK to FK, and vice versa you need to have these buttons localy accessible to the rigger, and having a rigger look through the nest of controllers to locate the IK tag is not convenient.   Keeping in mind here that the rig isnt for the rigger, its for the animator.

 

Dan

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5 hours ago, Rectro said:

Once you add the IK chain the rig becomes just that, a IK rig, you cant select the bones unless you move to FK within the IK tag slider.  Now the IK-FK slider can be used within a expresso for creating a driver control using user data, the key point here is the controls are easily accessible to the animator.  The issue here is two things.  At times you may want to use the IK to position the hand, then switch to FK to take over from that IK position.  By default the IK to FK slider does not work like this, its not a switch its a blend which means when you slide to FK you loose the IK position.  The only way is to use the Reset FK button within the IK tag, but this button can only be accesable via the IK tag so cant be rooted to be part of user data.  The second problem is, or at least makes it a bit more complex is you dont ever select bones of a proper rig, you select controlers that rotate the bones.  To do this you give priority to the controllers via constraints and now the IK tags reset FK no longer works as it only works on the bones, not the controllers.  This then leads to putting the IK on the controllers as in my file.

 

Out of this the issue remains, to switch, not blend between IK to FK, and vice versa you need to have these buttons localy accessible to the rigger, and having a rigger look through the nest of controllers to locate the IK tag is not convenient.   Keeping in mind here that the rig isnt for the rigger, its for the animator.

 

That's not true. Just because the IK tag is there it doesn't mean you cannot select the bones. In that file just select the bones and rotate them. It works and the IK will follow. At first glance, it actually is basically a live FK/IK rig simultaneously. It just would require you keyframe the values on the joints themselves to prevent popping and other issues.

 

The other thing I'd probably do is turn off align goal. Aligning the goal really does nothing good. It actually causes some pops in my quick testing of the file.

 

The way I would potentially use this setup would be to create a hierarchy of FK controllers, and apply the IK tag to that instead of joints. Then simply constrain joints to those controls. Then as far as switching between IK and FK, it would simply be hiding or unhiding some controls.

 

I'll have to run some tests, but it shows some promise. 

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1 hour ago, BretBays said:

 

That's not true. Just because the IK tag is there it doesn't mean you cannot select the bones. In that file just select the bones and rotate them. It works and the IK will follow. At first glance, it actually is basically a live FK/IK rig simultaneously. It just would require you keyframe the values on the joints themselves to prevent popping and other issues.

 

The other thing I'd probably do is turn off align goal. Aligning the goal really does nothing good. It actually causes some pops in my quick testing of the file.

 

The way I would potentially use this setup would be to create a hierarchy of FK controllers, and apply the IK tag to that instead of joints. Then simply constrain joints to those controls. Then as far as switching between IK and FK, it would simply be hiding or unhiding some controls.

 

I'll have to run some tests, but it shows some promise. 

Thanks Bret, your  right I can move the FK while the tag is still in IK mode, I didnt have Update On Goal turned on in the advanced tab.  Iv set this up how I think your describing it (see file)

 

Thanks Dan

 

 

IK-FK Switch-update on goal.c4d

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I did some more tests which are in the file below.  In my rig the thing to remember when switching from IK to FK is to select the joints by holding down the right mouse button and going over the circles and doing a keyframe for them.  This way the joints get their position from the FK before switching to IK.  This keeps it from jumping.  I've played around with animation before but this is the first time I'm taking it seriously.  Not trying to be harsh just trying to get my head around it all.

 

I am having a problem with the parent constraint in my test as the box is jumping and I don't know why.  If anybody knows how to fix this please let me know.

 

@kangddan  I tried out your rig.  It seems to work pretty well in most situations.  Having the one button press to switch is nice.  When trying to keyframe a test though I ran into a problem.  Please take a look in the file attached.  When switching to FK from IK the arm jumps to being straight.

 

@Rectro  What I get you are saying is you don't want the animator to change the bones directly because they could mess it up?   If this is right please look at my rig in the file below and let me know if it would work.  I turned off the appearance of the bones even thought they still are selecting bones.  This way they only need to click in the viewport to get it all working.

 

ik fk tests.zip

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1 hour ago, Fastbee said:

@Rectro  What I get you are saying is you don't want the animator to change the bones directly because they could mess it up?   If this is right please look at my rig in the file below and let me know if it would work.  I turned off the appearance of the bones even thought they still are selecting bones.  This way they only need to click in the viewport to get it all working.

A animator will not try to select the bones as they can be very difficult to select, and hard to find, although its good practice to colour code the bones from left to right.  A control rig also can be offset to the position of the joint yet retain its pivot location.  Controllers can be different shapes and colours which again makes it easier to select, this also helps avoids  controllers overlapping each other.  Controllers can be hidden as to speed up performance and not clutter the screen.  When switching between ik-fk your want to see only one set of controls, this is done via expresso, and user data.  Controllers can have a function other than selecting joints and being the controller, your need to set up a hierarchy of controllers mixed with IK goals to set up a reverse foot rig.  Controllers can all be kept together while the bones are hidden.  You can have user data on controlers to activate certain features.  

 

Making the bone size larger gives you better visuals as in your file but non of the above control, and for a full character things would get rather messy visually.  Im sure there are more technical reasons why a control rig is needed but Im not a high end rigger yet, iv got a way to go.

 

This is a nice basic guide.

https://www.pluralsight.com/blog/film-games/rigging-guideline-artist-whats-important-good-rig

 

Sorry to OP this thread has gone off topic.

 

Dan

 

 

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