Looking for advanced info on Carrara IK - Page 2 - Polyloop

Couerl · 26th October 2007, 07:26

I went ahead and set it up a little better for C6, the new bones make it a little tedious, but they also have some newer and better options too. I set the targets to red and blue for the forks and tomorrow I'll look into setting it up for NLA. If it's okay with you I'll test the area you were having problems with. It's pretty rare that I ever even bother with IK targets and for simpler bipeds or even 6 leggy's I'll usually just set up the rig the way I want it. I could get rid of all the targets and set up the rig with limited ball joins for direct manipulation of the skeleton, but that would take a while. Anyway, if you don't mind I'll try and get it setup nice for C6 and see what happens. Real nice work on this it looks like.

Steven

Couerl · 26th October 2007, 07:33

Oh, a little note on this, when I sent the bones back to their reference position or "zero-pose", I noticed that a few of the IK targets were a little away from where I think they should have been. This may inadvertantly cause the odd behavior in your number 10 chain. It's just a theory at this point though and take it with a grain of salt, but anything off looking on a rig of this complexity could add up I suppose.

And one last question before bed time, was the mesh made in Max or Maya or something? It has an interesting mix of tris and quads and it might help to clean up the arms and make it all quads, but it's not critical or anything, it would just speed up renders a touch I think annd maybe with some smoothing behave a little better too. Just thinking out loud...

DaveH · 26th October 2007, 17:02

If you do a draft render you can see the kind of effect I'm going for fairly quickly. Is C5.1Pro able to let me do that reliably/cleanly, perhaps with more cumbersome tinkering to the rig? Or am I beating my head against a wall?

> Wesgraphics: Just trying to guess what is being discussed here without it ever being said.

This thread veered slightly from the original intent, which was essentially "what resources could a dumb guy (me) buy/Google/whatever that could help explain nuances of IK and Carrara". The project driving me to despair was noted in an early post on this thread:
http://forums.polyloop.net/carrara-e...hat-i-get.html

> Couerl: was the mesh made in Max or Maya or something?

This is a Frankenstein's monster kind of thing. The director bought the model somewhere in an .obj format and intended to use it as reference but execute the real thing using a puppet in a water tank. It was already posed, which was fine for static use. We chose to use the CG model rather than go practical for a number of reasons, but that meant I had to fix the model so it could be animated - undo the pose to something neutral, make all edges soft rather than hard, clean up a lot of the geometry, etc. Some of the oddness you're seeing could be because I (manually) made the tendril sections more detailed (original cross section was 3 or 4 sides) and also subdivided them once.

> Couerl: I noticed that a few of the IK targets were a little away from where I think they should have been.

Yeah, the reference pose on the rig is *close*, but not perfect. I figured that it wouldn't matter because even if the rig was primed in a certain direction it would at least be predictable.

Ha! Wrong again, Dave!

Also, not all tendrils use locators in the same manner. The rig evolved as I was animating it, and rather than go back and redo work with better yet not great rigging I left some tendrils alone.

> Couerl: I'll test the area you were having problems with.

Of course it's OK!

DaveH · 27th October 2007, 17:53

I want to stress that I started this thread asking for help finding/buying reference information so that I could understand what I'm doing and help myself. I did not mean for people to fix my model for me, and I hope no one has gotten that impression.

I truly appreciate that people are taking time to look at this. But I'm uncomfortable with others going to any effort unless something comes of it that I can understand and apply. I don't want people to put themselves out for a project they're not involved with.

C6 has been recommended as worth the upgrade, and I'm certainly not going to challenge that, but I can't justify the expense unless I'm confident about the decision, meaning I know *why* it will help me, and to get there I need to understand why C5.1 Pro won't work for me.

So I'd like reiterate the question I asked on the original thread, which was:

"How do I make it calculate the bend consistently? Better yet, what n00b mistake have I made, and how do I fix it?"

Couerl · 27th October 2007, 18:10

Well, there isn't anything out there to buy or find, at least nothing that is going to solve your problem here..

C6 is worth it for the NLA alone in a case like this because it allows you to layer the animation and blend it. Each arm in effect can be given its own animation group and that helps compartmentalize the whole thing so you can deal with individual aspects of the animation without screwing up the rest of it, plus the expense is minimal if you already have C5, what's 100 bucks these days when it comes to your job? If you're using C5 in a working pipeline there's zero reason not to upgrade..

In order to fix that one arm you really have to identify why it is behaving oddly for you (I haven't done that so don't worry about me going over the top as far as help goes) and I can only imagine it is a bad IK target helper or twisted/messed up bones.. Poser style figures can end up looking like pretzels too or bending in impossible positions if they are not setup exactly right (which nothing ever is to begin with). I might try to re-rig that one arm and see if that will get you by.

DaveH · 27th October 2007, 19:47

> In order to fix that one arm you really have to identify why it is behaving oddly for you

Right. I was hoping books or what not would help me understand better how things interact and then I could figure out what the problem is.

> I can only imagine it is a bad IK target helper or twisted/messed up bones.

That's the kind of thing I'm hoping for, because then maybe it can be fixed.

> I might try to re-rig that one arm and see if that will get you by.

If you do, could you do it in C5.1 so I can see the difference and apply it to the others, or if you do it in C6 can you describe what changes were made?

> if you already have C5, what's 100 bucks these days when it comes to your job?

The license is owned by the production company, and I already did some fancy talking to let me do this using their mothballed Carrara rather than practically. To upgrade I'd need to justify the cost, etc. Indie films are notoriously short on money...

Couerl · 28th October 2007, 02:39

I just let it render today and I think the geometry is just folding over on itself.
You should be able to fix that in C5 without much trouble.
Try making the center rotate with the top and bottom and see if that helps.

DaveH · 28th October 2007, 06:59

> Try making the center rotate with the top and bottom and see if that helps.

Sorry, I don't understand what you are referring to as the center, top, and bottom.

I just tried making the "wrist" of the a10 arm follow the arm portion and it looks OK for now, but I already tried it once. Then the arm popped the other way, so fixed the wrist to follow it. Then it popped back again and I created the thread in desparation because it seemed that whatever I did it was going to fight me.

three3dguy · 29th October 2007, 07:12

Quote:

Originally Posted by Couerl

Oh, a little note on this, when I sent the bones back to their reference position or "zero-pose", I noticed that a few of the IK targets were a little away from where I think they should have been. This may inadvertantly cause the odd behavior in your number 10 chain. It's just a theory at this point though and take it with a grain of salt, but anything off looking on a rig of this complexity could add up I suppose.

And one last question before bed time, was the mesh made in Max or Maya or something? It has an interesting mix of tris and quads and it might help to clean up the arms and make it all quads, but it's not critical or anything, it would just speed up renders a touch I think annd maybe with some smoothing behave a little better too. Just thinking out loud...

I haven't look yet in the manual (might even have problems finding it) but is there some way to use Carrara 6.02 to fix the tris back to all quads?

Couerl · 29th October 2007, 07:39

one by one... It's not so much that they absolutely need fixing though, the problems of snapping and so forth come in to play when geometry crosses over itself and at least in this render, it's twisting the mesh apart..

DaveH · 29th October 2007, 14:47

It sounds like people are looking at different problems. There's some discussion of mesh distortion problems, which I know it does in the body when the clavicle bones rotate.

But I'm less worried about that than I am about controlling the direction that the IK solver chooses for directing the bend in any given chain.

I got approval for upgrade to 6 if I can show how it would help. It doesn't need to be so extreme that 5.1 can't fix it, either - it would be enough to show that 6 will make something easier. But before I do anything I need to understand what's wrong with my IK chains that's preventing me from controlling their bend direction.

Couerl · 29th October 2007, 15:55

Well see that's just it, the bones are attached to the geometry and if the geometry does something "impossible" so will the IK/bones..

I think the funny bend you are seeing is the result of the geometry flipping, and thus the IK/rig flipping too.

DaveH · 29th October 2007, 17:48

Wow. That is so not intuitive, and so not what I've experienced with other systems, even this one (though my experience is limited). I'm used to the vertices being completely at the mercy of bones and weighting. I'd love to sit down with a Carrara developer, programmer to programmer, and find out what's going on.

So what aspect of the mesh on the arms might be buggered in a way that it's interfering with the IK solver?

Couerl · 29th October 2007, 18:02

It may not have anything to do with that arm, it may be a case of geometry flipping on another arm or the trunk, (my suspicion) and thus causing the rig to flip on the number 10 arm. It's also possible to flip the orientation on a rig if you duplicate it with symmetry so that the duplicated chain does the opposite of the original as far as manipulation goes.
If the geometry were completely at the mercy of the rig, (which it is without IK on) then you'd be able to take any old Poser figure and flip the whole thing inside out. The IK is there to keep the rig and geometry intact by simulating joint behavior under normal physical rules, I.E. not being able to bend your elbow backwards beyond a certain point etc.. If you do bend the elbow backwards and "flip it", you may get unpredictable results. Anyway, if you can get C6 I reccomend it, that way you can animate each arm independant of the others and blend it all. I can help you get started with that easily enough if you like.

DaveH · 2nd November 2007, 16:55

> you can animate each arm independant of the others and blend it all

Had to digest all of this and deal with Real Life(TM) issues. I'm back to it.

Would I need to start over with the animation, or could I do something like take what I have and isolate each arm's movement for later tweaking and blending?

Couerl · 2nd November 2007, 17:11

Hmm, well... I didn't really do much to the rig or model or animation at all. The only thing I did was change the display on the last bone of each tree so they didn't look blown up (this is a common thing bringing C5 rigs into C6) and then change the colors of the tarket helpers in the IK so they were easier to spot. If you upgraded then all you'd need to do is save the model once at a "zero pose" and then make whatever different poses you liked and "bake" or really save them into the animation group as poses. once these poses are done you just drag and drop and blend the NLA wherever you like on the timeline. It's pretty easy once you get the steps sorted out and you could just use one animation group for the whole thing if you wanted to making it even easier.

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26th October 2007, 07:33	#22 (permalink)
Couerl Polygurbs Join Date: Jul 2005 Location: Denver Posts: 1,294	Oh, a little note on this, when I sent the bones back to their reference position or "zero-pose", I noticed that a few of the IK targets were a little away from where I think they should have been. This may inadvertantly cause the odd behavior in your number 10 chain. It's just a theory at this point though and take it with a grain of salt, but anything off looking on a rig of this complexity could add up I suppose. And one last question before bed time, was the mesh made in Max or Maya or something? It has an interesting mix of tris and quads and it might help to clean up the arms and make it all quads, but it's not critical or anything, it would just speed up renders a touch I think annd maybe with some smoothing behave a little better too. Just thinking out loud...

26th October 2007, 17:02	#23 (permalink)
DaveH Spline Join Date: Sep 2007 Posts: 44	If you do a draft render you can see the kind of effect I'm going for fairly quickly. Is C5.1Pro able to let me do that reliably/cleanly, perhaps with more cumbersome tinkering to the rig? Or am I beating my head against a wall? > Wesgraphics: Just trying to guess what is being discussed here without it ever being said. This thread veered slightly from the original intent, which was essentially "what resources could a dumb guy (me) buy/Google/whatever that could help explain nuances of IK and Carrara". The project driving me to despair was noted in an early post on this thread: http://forums.polyloop.net/carrara-e...hat-i-get.html > Couerl: was the mesh made in Max or Maya or something? This is a Frankenstein's monster kind of thing. The director bought the model somewhere in an .obj format and intended to use it as reference but execute the real thing using a puppet in a water tank. It was already posed, which was fine for static use. We chose to use the CG model rather than go practical for a number of reasons, but that meant I had to fix the model so it could be animated - undo the pose to something neutral, make all edges soft rather than hard, clean up a lot of the geometry, etc. Some of the oddness you're seeing could be because I (manually) made the tendril sections more detailed (original cross section was 3 or 4 sides) and also subdivided them once. > Couerl: I noticed that a few of the IK targets were a little away from where I think they should have been. Yeah, the reference pose on the rig is close, but not perfect. I figured that it wouldn't matter because even if the rig was primed in a certain direction it would at least be predictable. Ha! Wrong again, Dave! Also, not all tendrils use locators in the same manner. The rig evolved as I was animating it, and rather than go back and redo work with better yet not great rigging I left some tendrils alone. > Couerl: I'll test the area you were having problems with. Of course it's OK!

27th October 2007, 17:53	#24 (permalink)
DaveH Spline Join Date: Sep 2007 Posts: 44	I want to stress that I started this thread asking for help finding/buying reference information so that I could understand what I'm doing and help myself. I did not mean for people to fix my model for me, and I hope no one has gotten that impression. I truly appreciate that people are taking time to look at this. But I'm uncomfortable with others going to any effort unless something comes of it that I can understand and apply. I don't want people to put themselves out for a project they're not involved with. C6 has been recommended as worth the upgrade, and I'm certainly not going to challenge that, but I can't justify the expense unless I'm confident about the decision, meaning I know why it will help me, and to get there I need to understand why C5.1 Pro won't work for me. So I'd like reiterate the question I asked on the original thread, which was: "How do I make it calculate the bend consistently? Better yet, what n00b mistake have I made, and how do I fix it?"

27th October 2007, 18:10	#25 (permalink)
Couerl Polygurbs Join Date: Jul 2005 Location: Denver Posts: 1,294	Well, there isn't anything out there to buy or find, at least nothing that is going to solve your problem here.. C6 is worth it for the NLA alone in a case like this because it allows you to layer the animation and blend it. Each arm in effect can be given its own animation group and that helps compartmentalize the whole thing so you can deal with individual aspects of the animation without screwing up the rest of it, plus the expense is minimal if you already have C5, what's 100 bucks these days when it comes to your job? If you're using C5 in a working pipeline there's zero reason not to upgrade.. In order to fix that one arm you really have to identify why it is behaving oddly for you (I haven't done that so don't worry about me going over the top as far as help goes) and I can only imagine it is a bad IK target helper or twisted/messed up bones.. Poser style figures can end up looking like pretzels too or bending in impossible positions if they are not setup exactly right (which nothing ever is to begin with). I might try to re-rig that one arm and see if that will get you by.

27th October 2007, 19:47	#26 (permalink)
DaveH Spline Join Date: Sep 2007 Posts: 44	> In order to fix that one arm you really have to identify why it is behaving oddly for you Right. I was hoping books or what not would help me understand better how things interact and then I could figure out what the problem is. > I can only imagine it is a bad IK target helper or twisted/messed up bones. That's the kind of thing I'm hoping for, because then maybe it can be fixed. > I might try to re-rig that one arm and see if that will get you by. If you do, could you do it in C5.1 so I can see the difference and apply it to the others, or if you do it in C6 can you describe what changes were made? > if you already have C5, what's 100 bucks these days when it comes to your job? The license is owned by the production company, and I already did some fancy talking to let me do this using their mothballed Carrara rather than practically. To upgrade I'd need to justify the cost, etc. Indie films are notoriously short on money...

28th October 2007, 02:39	#27 (permalink)
Couerl Polygurbs Join Date: Jul 2005 Location: Denver Posts: 1,294	I just let it render today and I think the geometry is just folding over on itself. You should be able to fix that in C5 without much trouble. Try making the center rotate with the top and bottom and see if that helps.

28th October 2007, 06:59	#28 (permalink)
DaveH Spline Join Date: Sep 2007 Posts: 44	> Try making the center rotate with the top and bottom and see if that helps. Sorry, I don't understand what you are referring to as the center, top, and bottom. I just tried making the "wrist" of the a10 arm follow the arm portion and it looks OK for now, but I already tried it once. Then the arm popped the other way, so fixed the wrist to follow it. Then it popped back again and I created the thread in desparation because it seemed that whatever I did it was going to fight me.

29th October 2007, 07:39	#30 (permalink)
Couerl Polygurbs Join Date: Jul 2005 Location: Denver Posts: 1,294	one by one... It's not so much that they absolutely need fixing though, the problems of snapping and so forth come in to play when geometry crosses over itself and at least in this render, it's twisting the mesh apart..

29th October 2007, 14:47	#31 (permalink)
DaveH Spline Join Date: Sep 2007 Posts: 44	It sounds like people are looking at different problems. There's some discussion of mesh distortion problems, which I know it does in the body when the clavicle bones rotate. But I'm less worried about that than I am about controlling the direction that the IK solver chooses for directing the bend in any given chain. I got approval for upgrade to 6 if I can show how it would help. It doesn't need to be so extreme that 5.1 can't fix it, either - it would be enough to show that 6 will make something easier. But before I do anything I need to understand what's wrong with my IK chains that's preventing me from controlling their bend direction.

29th October 2007, 15:55	#32 (permalink)
Couerl Polygurbs Join Date: Jul 2005 Location: Denver Posts: 1,294	Well see that's just it, the bones are attached to the geometry and if the geometry does something "impossible" so will the IK/bones.. I think the funny bend you are seeing is the result of the geometry flipping, and thus the IK/rig flipping too.

29th October 2007, 17:48	#33 (permalink)
DaveH Spline Join Date: Sep 2007 Posts: 44	Wow. That is so not intuitive, and so not what I've experienced with other systems, even this one (though my experience is limited). I'm used to the vertices being completely at the mercy of bones and weighting. I'd love to sit down with a Carrara developer, programmer to programmer, and find out what's going on. So what aspect of the mesh on the arms might be buggered in a way that it's interfering with the IK solver?

29th October 2007, 18:02	#34 (permalink)
Couerl Polygurbs Join Date: Jul 2005 Location: Denver Posts: 1,294	It may not have anything to do with that arm, it may be a case of geometry flipping on another arm or the trunk, (my suspicion) and thus causing the rig to flip on the number 10 arm. It's also possible to flip the orientation on a rig if you duplicate it with symmetry so that the duplicated chain does the opposite of the original as far as manipulation goes. If the geometry were completely at the mercy of the rig, (which it is without IK on) then you'd be able to take any old Poser figure and flip the whole thing inside out. The IK is there to keep the rig and geometry intact by simulating joint behavior under normal physical rules, I.E. not being able to bend your elbow backwards beyond a certain point etc.. If you do bend the elbow backwards and "flip it", you may get unpredictable results. Anyway, if you can get C6 I reccomend it, that way you can animate each arm independant of the others and blend it all. I can help you get started with that easily enough if you like.

2nd November 2007, 16:55	#35 (permalink)
DaveH Spline Join Date: Sep 2007 Posts: 44	> you can animate each arm independant of the others and blend it all Had to digest all of this and deal with Real Life(TM) issues. I'm back to it. Would I need to start over with the animation, or could I do something like take what I have and isolate each arm's movement for later tweaking and blending?

2nd November 2007, 17:11	#36 (permalink)
Couerl Polygurbs Join Date: Jul 2005 Location: Denver Posts: 1,294	Hmm, well... I didn't really do much to the rig or model or animation at all. The only thing I did was change the display on the last bone of each tree so they didn't look blown up (this is a common thing bringing C5 rigs into C6) and then change the colors of the tarket helpers in the IK so they were easier to spot. If you upgraded then all you'd need to do is save the model once at a "zero pose" and then make whatever different poses you liked and "bake" or really save them into the animation group as poses. once these poses are done you just drag and drop and blend the NLA wherever you like on the timeline. It's pretty easy once you get the steps sorted out and you could just use one animation group for the whole thing if you wanted to making it even easier.