View Full Version : skelegons/bones/goal target issue

10-28-2004, 04:42 PM
Hi e-body,

I am continuously reminded by LW that I am still at the very begining of
knowing LW.
and as so here I am back with another issue if there is anybody who could assit me with that one.

It is about skelegons, bones and Goal Targeting. Here it is:

1. I have created a 3 sections box.
2. Then I have created 3 skelegons in the middle of the box, on the same Layer.
3. I have saved the object then I have loaded it to Layout.

So far so god, but after converting the skelegons to bones it was mess:

1. Goal targeting does not work on bones created in Modeler.
2. When I kreated Drew bones/children in Layout they did not work either.
3. When I finaly Added bones/childrens it worked instead I have lost control over the box.

No matter if the bones was active inverse kinetics was set "ON" it just refused to work.

I did read the manual but I could not find anything about assigning objects to
bones targeted at Goal and with inverse kinetics active.

I am just loosing patiance since I can not find any way out.
Somebody please help me.

czesiu :confused:

10-29-2004, 03:34 AM
Send me the mesh :)

10-29-2004, 04:29 AM
Hi Dodgy,

Here is a mesh and the image with it.

When bones created in Modeler it is impossible to to parent the Bones 1 to IK Chain point.
It makes neither different if the bones 3 is Goal targeted to The Goal point it does not work anyway.

Does it work for you?

czesiu :confused:

10-29-2004, 07:10 AM
Okay, some quick notes.

You CAN'T Parent bones to any object other than the object they are built for. If you want the bones separate, but able to affect your mesh, make them in a different layer and use the 'Use Bones from' Field in the bones properties of the mesh object.

You CAN use IK on bones created in Modeler. You just don't know how to set it up correctly.

For each bone in the IK chain, you must set each channel controller to IK. You do that in the Motion options for each bone. (you can also do this in the spreadsheet)

LW allows you to do per channel IK, in that an object can have IK on JUST H or JUST P or JUST B, OR any combination of those.

Then you must select (for the end of the chain) the Goal object (again, this is done in the Motion options panel), and set the 'Full time IK' toggle on if you so wish.

10-29-2004, 12:35 PM
Thanks a lot for that Dodgy.
Please et me digest it a bit and I will see what I will get out of it, okey.

czesiu :)

10-29-2004, 02:43 PM

I am back and I will thank you a lot for the tip.
In some way I have managed to get it work.
This was the good news.

The bad one is that:

I don't get it why the object bends only in one direction.
Please check the Zip file. There you can see that untill frame 40 object bends
correctly but after the frame 40 to the other side of the axis it bends wrong way.

Note! That all Keys has the the same positions but on the opisite sides of the

Do you know whay is going on and how to make object bend right or as I want.

czesiu :)

10-29-2004, 10:29 PM
You need to prebend your bone chain to let LWs IK solver know which way its supposed to bend. Once you do that and only set IK on the necessary channels it should behave better.

10-30-2004, 02:34 AM
Hi SplineGod,

Thanks, I do not know if I get you right but what I did was
that I have limited the angle on the channel to 0 degrees in Max bar Pitch controller.

This makes that the bones are forced to bend inother direction.

I am not 100% satisfied of that solution since it means that every time
I need some aother movement I have to change the Min and Max value
in all bones that are affected by movement, but it is some solution.

Thanks again.

czesiu :)

10-30-2004, 11:56 AM
Are you trying to create an arm or just a tentacle? LWs native IK doesnt handle long IK chains as well as it should. Adding IK Booster improves that aspect.

10-30-2004, 06:20 PM
Well, actualy some in between.

It is an arrow that is ment to fly and bend in flight.
Check the Zip.


10-30-2004, 07:55 PM
I think I would probably just select all the bones and rotate them addively rather then bother with IK. You could setup the bones in the arrow to start in the middle and do it using 2 chains. One chain goes towards the tip and the other towards the end. If all the bones are selected at the same time they will rotate additively.
You can also use the built in spline deformer or any of the free ones like Shift Spline Transform or FIs bezier bend. Even LWs bend deformer could probably handle this easily enough. :)

10-31-2004, 01:35 AM

It seem that some simple, thought, tasks can be very tricky when it takes 3D modeling/animating.
I have never thought that this will be the case when I started it.

I have tried slightly different way than that you described.
I started a bones chain in the end of the arrow and the front of the chain was the tip of the arrow, just in the arrow direction.

What I have got was motion path for each one bone and arrow it self, which ended in big number of keys and splines.

I will try your way of tackling tha problem.

After all, all ways are good for me to try, since even if no all of the ways solve the problem I am always learning someting new of it.

Will let you know when I solve the problem and how, If I solve it?

czesiu :)

10-31-2004, 08:48 AM
Ill be interested in what you come up with. Ive had to do similar things myself and its not really very hard at all. Another thought is to use DStorms Trailer plugin. It will bend the arrow to conform to its own motion path. and its free. :)

10-31-2004, 10:32 PM
Ill be interested in what you come up with. Ive had to do similar things myself and its not really very hard at all. Another thought is to use DStorms Trailer plugin. It will bend the arrow to conform to its own motion path. and its free. :)

Can you be kind and write where to get the DStorm Trailer?
I have been searching on the net and could not find it.

czesiu :)

10-31-2004, 10:40 PM
Go to the plugins section on flay.com and type in trailer. :)

10-31-2004, 10:42 PM
Go to the plugins section on flay.com and type in trailer. :)

czesiu :)

11-01-2004, 01:30 AM
No problem! Let me know if that works for you. :)