View Full Version : "Skelegons" my nemisis

08-17-2006, 06:08 PM
Hey everyone I've finished my first model, its of a walking robot that has human movements. Now I've heard that using skelegons would allow me to make pivot points and joints that would allow me to manipulate the model without having to select every darn polygon then rotate everything individualy.

My question is how do I use Skelegons, I've serched the help stuff within lightwave and I still don't know the head from the arse with this stuff, any help, suggestions of what to use and how or links to tutorials would be much appriciated.

Please be nice :newhere:

08-17-2006, 06:12 PM
Layout > Setup > Convert Skelegons to Bones



We're always nice. You're a fellow traveller, we've got nothing to take out on you chap.

08-17-2006, 06:30 PM
Thats good to know I'm gonna be asking alot of questions i can assure you that, but see I don't know how to use the skelegon creation tool, I'm stuck because I have no idea of where to place (I'm assumimg at joints) the skelegons and how to assign them to a set of polygons (an arm, leg etc).

08-17-2006, 07:02 PM
We loves questions, 'cause that makes us break down what we think we already know into explainable bits, which generally boosts our own understandings.

08-17-2006, 07:28 PM
There's some bones and rigging tutorials for free from 3dgarage.com
There from Dan Ablans Inside LW 8 Book. (Always an excellent source of reading material - look out for Inside LW 9 - same author)

Here's one from Newtek on the subject in question.

And here's loads more free tutorials from Newtek

And Here's their free video tutorials

Should say animating in LW is a huge subject, your best bet is to go though the tutorials mentioned above (there's thousands more on the net), and see if you can find a method that works for you. Because you're animating a robot I should also mention that you can use pivot points and IK without actually using bones at all. If you have LW 8, go through the demonstration scenes in the 'scenes' directory, there's one of an industrial robot animated using this very method.

Have Fun :)

08-18-2006, 02:08 PM
Thanks so much, looks like I got alot of reading ahead of me, i'll post something of my model when it's alittle more up to standards and skinned.:thumbsup:

08-18-2006, 08:21 PM
I found the robot you were talking about and I see where the pivot points are and they would probably work better for me as alot of the joints in my model are pivot joints. How do work with those and what is an IK????

08-19-2006, 05:26 AM
Converting Skelegons in Layout isn't much use unless you have drawn them first in modeler, on a layer beneath the mesh you want to deform.

That's easy. Draw a box, extend it so there are ten sections on the x axis and one on the z and y.
A tube, whatever... then draw three skelegons on the next layer so they correspond then cut and paste them back into the object layer.

I haven't seen your model but to use skelegons that way, they apply to the one layer and the one mesh since you aren't making an IK chain out of each layer.

-You make your skelegon drawing on the layer beneath the mesh, then copy it to that layer then send it to layout, then you convert skelegons to bones.

Once done, you will see that it's hard to know beforehand where to place them.

I reckon it's easier to load your object into Layout first, go to the scene editor and you will see a display type button to the left of the object's name... select "front faced wireframe" as the display mode.

Then go to the same object's properties panel "p" and cut the subpatch display level back to 1 and the subdivision order to last. The object will then reveal it's status in animation.

Then you add bones using the = key and arrange them with the "tip mover" etc and then use "add child bone" to the selected parent to lengthen the chain.

When you have done a few and want to check how the deformation is going , hit "r" to set the rest position for each bone as you cycle through them using the up arrow key. As in activate them, or relate them to the mesh.

Rotate a few and you will get a better idea of how positioning bones deforms what kind of mesh than you will mucking around trying to get skelegons right straight up.

Even if you don't know how to set up the IK from there this way will give you a better idea of what you are dealing with than skelegons in modeler will.


08-19-2006, 05:56 AM
Bladewing51 -

I found the robot you were talking about and I see where the pivot points are and they would probably work better for me as alot of the joints in my model are pivot joints. How do work with those and what is an IK????

OK, a pivot point is simply an objects point of rotation. When you build your model, the pivot point by default is at the centre of the darker grid lines in each view port, or x=0, y=0, z=0.

IK is short for inverse kinematics, it's essentialy a way of letting lightwave calculate how objects in a heirarchy can move. There's also FK, or forward kinematics. Explanations on how each of these work is wild and varied and can be equal to explaining the 'offside rule' in football (soccer) to someone who's never watched the game :). Google 'IK Chain' for an in depth explanation. Sorry I can't be more in depth here but there's a bacon sandwich beside me with my name it.

Without further ado, here's a tutorial from the archives on how to build a robot arm using pivot points - exactly what your looking for I think :)


08-19-2006, 03:10 PM
That Tut helped so much, that was what I was looking for I finally got motion :D, Now anyone got any good suggestions about shocks, as in a car shock absorber, anyone ever made one in LW and actually made it work (In and out Motion whilest ancored to 2 points) I'm gonna do a google search and mess around in LW for awhile see if I can find anything but if anyone has a suggestion please feel free to post.

08-19-2006, 09:18 PM
yeah, you use 4 nulls.

The bottom tube has the 1st null as it's parent, then 2nd null as it's child.
The upper tube has the same setup and then you make the 3rd null, or the parent of the upper tube a goal object for null 2, and null 4 the goal object of null 1.

Pitch is set to inverse kinematics in the motion options panel and the nulls with goals are full time IK. There is a tute out there but I can't remember where.




You are better off using an endomorph because then you can have four shock absorbers, one for each wheel without giving yourself a pain in the neck.


08-20-2006, 06:45 AM
What meshpig said :)

Here's a tutorial by Kurtis, It's in zip format and I haven't been through it, but it should certainly do the job.

Setting Up a Hydraulic Cylinder by Kurtis Harris.

08-20-2006, 10:18 AM
Cool, wow you can do almost anything with this program, its amazing, that tutorial was great, you should try it I learned alot about nulls but ya'll probably already know that stuff.
Thanks again

08-21-2006, 07:06 AM
Well good news I did that tutorial and ended up taking what I had learned their and applied it to my model BUT theres a problem I've done everything the same as before except now when I get the object to target the Null I have created the object points in the opposite direction as you see from my screenie.

The Null is the light blue cross at the knee cap and the orange dotted line seems to be the target link the Lower cylinder (Object) to the Null. How do I allign the cylinder with the Null so that cylinder faces the Nulls position.

08-21-2006, 07:46 AM
If your pistons are seperate models, go back into modeler and rotate 90 degrees around the pivot. Without knowing how you've modeled the pistons I can't tell you which axis to rotate (or which direction), so, time for experimentation :)

08-21-2006, 03:01 PM
Lol I never thought to go back to modeler I was searching layout like crazy thinking I could rotate the nulls to get it to work. Anyways I now have a fully working leg with working shocks BUT when my Shocks almost reach full extension the models try to flip themselves on the pivot point almost doing a 180 on the heading. Any Idea what this could be its very annoying??

08-21-2006, 07:42 PM
Reduce the size of your shocks, don't let them push or pull in unreasonable amounts, If the calcultions get flipped, you're in trouble. :)

08-23-2006, 03:00 PM
Hey I'm probably gonna move this to a new thread seeings how this is not about skelegons any longer, see you on that thread.