Using Sliders in Lightwave
Sliders are a great tool in Lightwave for simple rigging tasks. They can be used for many applications, though for me, it usually involves simple rigs for vehicles. By using them in conjunction with Cyclist to control physical components of the car including steering, doors, wings, and also simple suspension moves, it enables you to quickly pose a car for a rendered still (or animation). They are fully key-framed, making them very powerful.
This mini-tutorial shows you the basics of how to set-up sliders for a vehicle, in this case the Bugatti Veyron.
First quick task is to add a null for each element that we intend to animate and rig with sliders. Typically you would have steering and doors at the very least. The Veyron has some extras for it’s articulated wings. I am also going to add some nulls to control suspension in terms of the tail squat and nose diving, along with basic body roll. As I say, for full blown animation, you’d have proper automatic rigs, but for rendered stills these work great. All of these nulls can be left at world zero, as they are controlled via sliders once we are done, and are fine to be kept out of the way. Don’t worry if you miss one, you can add them at any time.
The steering wheel generally required special consideration. It doesn’t sit flat on any one axis usually (unless you orientate it as such in modeller), so we need to add a null rotated to effectively sit flat on top of the steering column, and then parent the steering wheel to it. this will allow the steering wheel to rotate correctly.
As mantioned in the introduction, we use Cyclist with Sliders. This means that for the main rear wing lift, we first keyframe the animation from the down position at frame 0, to lifted at frame 60 (you can use whatever end frame number you want).
We now have the motion of the rear wing lift animated. Cyclist works by effectively playing back animation based on input from a control null. Open the Motion Modifier settings for the component, and apply Cyclist.
In the Cyclist settings we specify which of our nulls will provide the input, as well as the start and end frame numbers for the animation range we want to use. You also specify the range of the control input, so 0 – 90° for example makes fine control easier than 0 – 30°. You will find the animation no longer works in layout when you scrub the time-line.
Once again, we add Cyclist, using frame 0 through to 30, and control range 0 through to 90° of Heading on the Door Left control null we added earlier. Door movement is no tied to the Door Left control null and it’s heading rotation.
Steering wheel is next. The wheel is parented to it’s null, and I animated this null to be banked at -170° at frame 0, 0° at frame 30, and 170° at frame 60. This gives the full left to right steering wheel rotation lock to lock. It is then linked to the steering control null with Cyclist using a control range of -90° to 90°. Frame range is the 60 frames that our lock to lock animation uses.
Next we have the nulls that control the car nose diving and tail squatting. The nose diving null is located centrally between the rear wheels, and parented to it is the tail squat null. This null is located centrally between the front wheels. Started with the nose dive null at the rear, add a slight pitch of around -1° or -2°.
Once again we link this to it’s control null with Cyclist, matching the frame range to that in the previous step, and specifying the range of movement for the control null (you’ll notice it’s normally based around a 90° range).
Finally we have a null for body roll, which your nose dive null should be parented too (look at the scene editor in the example). As long as you make sure you have Parent in Place enabled in Layout, you can shuffle things around in your scene hierarchy without too much bother. As you see, I have animated body roll bank from -2° through to 2° and key-framed 0° midway.
Cyclist is added in just the same way to the body roll null. We now have the ability to dip the front and rear of the car (indeed we can lower the car by adjusting both simultaneously). In addition we can roll the car body slightly either direction.
Add the Sliders
Selecting your master car null (to which ALL vehicle related items are parented), open the properties palette, and choose Sliders from the Custom Object drop down menu. Then double click Sliders in the Custom Object List. You’ll be presented with the Sliders configuration, with a list of all scene items in the left side. Each item can be expended to show available channels such as X, Y, Z, H, P, and B etc..
Find each of your control nulls, expand the channel for each and double click the channel you used for the Cyclist Control. Make sure the start and finish angle matches your Cyclist setting, and give it a custom label if you wish. Each slider will be assigned a different colour automatically, and you can override this if you want. You’ll see your floating list of Sliders grow as you add each one.
Using the Sliders
Using sliders is a breeze. When you want to make an adjustment, either hit your sliders hotkey, or go to the modify menu and select Sliders. You’ll notice that the Slider changes from a dotted line to a solid line. This shows you they are active. Then simply slide them and see your car components move.
A key-frame will be automatically created on any slider you move. If you hit the E envelope button, you’ll bring up a graph editor where you can adjust key-frames for any slider, and all the usual graph editor functions.
The four way arrow icon will let you drag the slider around the viewport (only when sliders are active), and the left/right arrow button allows you to stretch the width of the sliders on screen which can aid fine tuning (again only when sliders are active). You also have a single down arrow head which collapses and expands the sliders to de-clutter the screen.