List of Joints
Joint Description
Hinge Objects linked to this joint can spin around its center.
Servo Basically a controlled hinge, suitable to control arms, doors, and similar things.
Motor Another controlled hinge, built to control wheels - only maximum speed is available.
Slider Objects linked to this joint can move linearly between the maximum and minimum.
Piston The controlled version of the Slider joint.
Gyro (or gyroscope) Objects linked to this joint will have the corresponding axis locked.
Fixed This joint was made to fix an object to another. Its Breaking Force variable gives it various other uses.
Corkscrew Objects linked to this joint can spin around its axis and move between maximum and minimum.
Spring Objects linked to this joint can move linearily along its axis. The spring joint will try to bring attached objects back to their original position.
Ball Objects linked to this joint can rotate freely around the joint.
Universal Objects linked to this joint can rotate almost freely around the joint. Unlike the Ball one, the Universal joint won't allow the object to rotate around it's axis.
Gears The Gear joints are "gears" that don't need to mesh to act like gears.
Old joints
Magnet Attract all the objects. No longer works.
Oscillator Objects linked to this joint can move between the max and min. Now in place of those are used scripts.

What are joints for?Edit

SketchyPhysics joints make physics objects in the simulation behave differently; joints create virtual links between objects, making them move around each other, and attaching different objects together.

How to use themEdit

Connecting jointsEdit

To use most joints, you should have at least two objects and a SketchyPhysics floor in your model. Play the simulation, and notice how the objects are not connected in any way; they move freely of each other. Now, reset the simulation and try this: Select a hinge joint from the joints toolbar, and click on one of the objects; the point at which you click defines the origin of the joint. Moving your mouse away from this point will sketch a line which indicates the axis of rotation of the hinge. Clicking a second time will set the hinge's axis. Group the joint with the object you've made it on – now you have a jointed object, ready for connection. Select the Joint Connection Tool (JCT) from the SketchyPhysics toolbar, click once on the joint (make sure only the joint itself is highlighted, zoom in and click on it's outline) and then Ctrl+click or option (Mac) on the other object. Now you have a functioning joint! Play the simulation. Notice that not only are the two objects attached, but the attached object is able to swing around the hinge's axis. Because the physics are based on real-world laws, if either object is held still, the other will still be able to move around the axis of the hinge.

The same principal applies with all of the joints included in SketchyPhysics (With the exception of the Gyro). Create two or more objects, make a joint on one of them, group the joint and the object, connect the joint, and you have a functioning connection. Because jointed objects can be connected to other jointed objects, and you can have as many joints in one group as you wish, there is no limit to the complexity of the mechanisms you can create!

Disconnecting jointsEdit

To disconnect an object from a joint, click the JCT (zoom in and click it's outline) and Shift-click or Shift (Mac) the joint. They are now disconnected.

Note that deleting a joint before disconnecting it might cause the JCT to get confused.

Joint attributesEdit

If you right click a joint you can edit its joint settings. Each type of joint has its own settings. You can access the settings by clicking on the UI button next to the simulation reset button and then clicking on the joint.

If you have trouble clicking the joint, zoom in and click it's outline.

To make sure the attribute data entered stays in the field, always follow the edit by clicking in one of the other fields (data entry slots).

Joints (Advanced)Edit

Once you're happy with the basics outlined above, you can move onto the more advanced aspects, including real-time control of the joints, and even scripts to control them! (See Ruby for more info)

An object that is linked to a joint will be influenced more strongly if the joint is physically attached to it. If a linked object is moved away from a joint during the building phase of the project (before the simulation is played), the joint's control will be reduced. This can be seen by creating a number of objects at different distances from a joint, and then linking them each to the same joint. When the simulation is started, the objects will behave differently. Try it out for yourself!