Easy-to-follow video tutorials help you learn software, creative, and business skills.Become a member
With the simple bone structure like this or with a complex one, sometimes you want to move it around with a little bit more ease. Now this works pretty well just to select one of these bones and press the Y command to rotate it and give this character a little life, but every once in a while you might want a little more control, like you possibly might want to grab the tip of it here and kind of move it around a bit. It might be little easier. So let me show you how to do that with Inverse Kinematics. I am going to select the bottle here and I am just going to move it over. I am going to go to Items and say Add Null and we'll call this Base, something like that, and with that Base object, I am going to go to Setup and Add > Bone.
Easy enough, just like we did earlier for the little bottle. Then I am going to press my Equal key on the keyboard and add a few child bones, just like that. Then I am going to take that last bone and I am going to press the P key and I want to change the Rest Length for this one. The reason being is that all rotations and positions and movements all happen from the base of the bone. So if I want to grab the tip here, well that one bone will be kind of sticking out. I want to be grabbing it from the bottom here, making this one our top bone. So I am going to bring the Rest Length down like that and basically there's not much distinction now between the base or the tip, which is kind of the whole point.
Also with a smaller Rest Length, it's going to have a lot less influence, if any, on an object. Back in Items, I am going to add another Null object and call this Goal and then I am going to move that item all the way to the tip, like that, and that's going to be our control point. Now, if you wanted to give this a little more life as far as visibility, press the P key for that object and you can go to Add Custom Object and you can choose Item Shape and if you double-click this, you'll get a nice little panel that comes up. This panel is visible when you actually created your null object and if you forgot to do it, this is how you get back to it. And with this you can change the shape to maybe something like a pyramid, a diamond, a sphere and so on, and you can change the shape of it and the size.
That helps you really identify where those control handles are when you're setting them up. What I am going to do now is tell these bones that that is the goal. Basically I am going to have this hierarchy and this is what is really important when setting up Inverse Kinematics. Let's open up the classic Scene Editor and notice that I've got the base bone all the way through. I am taking yhis last bone. Here are all the others. This last bone, I am going to goal it. I am going to tell the Inverse Kinematics engine, point to that goal and that then is going to control all the other bones. The way to do that, if you press M for Motion Options for that selected bone, that will be the last one, up under IK and Modifiers there is a section for Goal Object. Well, the goal is that null object we named Goal and you can see a line draw all the way through there.
If I select that object now and I move it, you can see there is a dotted line. So I know something is working, but the bones haven't been told to be set for Inverse Kinematics yet. So what I am doing is I am holding the Shift key and I am selecting all those bones at once and then still under Motion Options for Bones, under Controllers and Limits, there is a Rotation tab. Under Heading Controller change that to Inverse Kinematics. For Pitch same thing and for Bank same thing. And then when I select this and press the T key for move, my bones move.
Now I can grab this whole chain and move it around, just simply by moving this one little control. If your bones are not moving and you've set this up property, make sure that under the Setup tab, under the General category, under More, make sure Enable Inverse Kinematics is on, okay? I've been victim to thinking something is not working because that was off. And what happens now if you think of what I showed you earlier, how the bones deform an object, well, now you have a control handle to move that deformation around. So let's go one step further and take our bottle here and do the same thing.
I want to control it from the very tip. So I am going to select that top bone and I am going to add a child bone. You can even call this a TipBone if you want. I'll press P to get to the Object Properties for that bone and I am going to move that down, just bring that Rest Length all the way down. Close the panel, go to Items, you can add a null object, and we'll call this Goal. And here under Edit, if you open that up, I can change my Shape to maybe a Ball and I can make it a good size if I want.
Draw a line to my Goal if I want, put a label, Goal, and so on. You can select a color and unselect a color, just the nice options for your display. Now my goal is by default right here at the (0,0) axis and my bottle is all the way over here. That's okay because I can just move this and then right-click and move it up. And let's always check it from the Top View just so we know that it's right on the top there. I'll press 2 on my keyboard. I'll press 3 to go to a Side view and then 4 to go back to Perspective. From here I want to take that top bone and set the Goal to that null object.
That's sometimes hard to do because it's such a tiny bone. So what I like to do is select one of the bones I can see and then just press my up or down arrow to cycle through it. Then press the M key on your keyboard to get the Motion Options. Go back to IK and Modifiers and the Goal Object is now the Goal. Don't be confused with our first goal that we did over on the other side there. That's Goal (1). We wanted the Goal (2), which is right there. Then I am going to hold the Shift key and select all these other bones, go to Controllers and Limits, and for the Rotation put on Inverse Kinematics.
When I select that goal in Layout and press the T key for move, not only am I deforming my object, but I'm controlling all of the bones with one movement. So Inverse Kinematics is not that difficult to set up once you have your bones and your deformation in place. That being said, you don't have to use bones to use Inverse Kinematics. If you have a series of objects like a simple lamp or a robotic arm, those objects in the hierarchy can also work with IK.
You can put a base object and parent to that as the middle object like an arm, parent to that is a hand, and then from there you can set up an IK goal with a null object just like this and have a very nice workable controllable object. Inverse Kinematics are good for very simple objects like robotic arms in a factory or very complex objects like full rigged character with arms and legs and a head and eyeballs and everything else. You can take it from a very simple object to a very complex object all with the same tools in LightWave 3D.
Get unlimited access to all courses for just $25/month.Become a member
107 Video lessons · 32801 Viewers
94 Video lessons · 22723 Viewers
78 Video lessons · 8959 Viewers
83 Video lessons · 8277 Viewers
Access exercise files from a button right under the course name.
Search within course videos and transcripts, and jump right to the results.
Remove icons showing you already watched videos if you want to start over.
Make the video wide, narrow, full-screen, or pop the player out of the page into its own window.
Click on text in the transcript to jump to that spot in the video. As the video plays, the relevant spot in the transcript will be highlighted.
Your file was successfully uploaded.