Logic Gadgets: Bolt

Icon bolt
Name of gadget Bolt
Section Connectors
Number of Tweak pages 1 (of 3 rotational connector types)
Author LadylexUK, QuietlyWrong
Last updated 07 August 2019 [EA v1.07]


Any time you want an object to be able to rotate relative to another one, consider the humble Bolt connector. Whether you’re putting wheels on your barrow or hinges on a door, the Bolt is ready and waiting.

Like all connectors, you’ll need a parent object and a child object that will turn round relative to the pivot on the parent. The pivot point is the critical part of the connector – all rotation will be centred on this point, and it also specifies the direction in which rotation takes place (rotation is restricted to a single axis, unlike with the Ball Joint connector)

As with all connectors, you use it by first connecting it to the parent object, then to the child. A third, pink gizmo, the “pivot gizmo” will automatically appear between the two and can then be dragged into position – all rotation will be centred at the pivot and you can rotate the pivot gizmo to whatever angle you need.

If you want to limit the range of rotation, as with a door hinge, you can tweak the connector accordingly, at which point additional gizmos will appear, as shown here, to indicate the maximum angle. You can grab and adjust these as required. In appearance, the Bolt is almost indistinguishable from the Motor Bolt – though the latter does show a faint line spinning about the pivot to indicate the speed and direction of its motion.

Bolt Gizmos

The Bolt is meant for objects that will rotate when interacted with – whether by the player, or the bumps and gravitational forces of Dreams physics. If you want a connector that can turn an object or spin it to a specific position according to logic, you should switch to the Motor Bolt.


Example Tutorial (adapted from Media Molecule)

  1. Let’s make that door on a hinge. Go to sculpt mode.
  2. Turn on grid snap.
  3. Select cube and edit shape.
  4. Stretch the cube out to look like a door.
  5. Stamp it down.
  6. Start new sculpture.
  7. Repeat steps 3 to 5 to make some sort of lintel for the door.
  8. Go back to assembly mode.
  9. Line the door up with your lintel.
  10. Get a bolt from the gadgets menu.
  11. Connect the parent gizmo to the lintel (the stationary part).
  12. Connect the child gizmo to the door (the moving part).
  13. Grab the (pink) pivot gizmo and move it to the edge of the door where you imagine it to be hinged.
  14. Rotate the pivot gizmo so that its rotational axis is vertical. The way the connector is displayed should indicate that circular motion within a horizontal plane.
  15. Now grab your door and move it – it should swing round in place like a door!
  16. Try tweaking the Use Limits option and adjust the gizmos on the door until it is limited to a realistic range of motion!


Tweak Menus

Bolt tweaks
  1. Connector Type
  2. Tightness
    2a. Input
    2b. Output
  3. Springiness
    3a. Input
    3b. Output
  4. Collide with Connected
    4a. Input
    4b. Output
  5. Use Limits
    5a. Input
    5b. Output
  6. Angle Limits Range
    6a. Input
    6b. Output
  7. Connector Completion
    7b. Output
  8. Power
  1. Connector Type
    Here you can change the type of rotational connector without having to create a new one; the same connection points between parent and child will be maintained.

  2. Tightness
    This setting determines the ease with which the joint can be moved by external forces (as opposed to, for example, animation keyframes). At 0%, it can be rotated freely; at 100% it will be difficult to budge.
  3. Springiness
    This setting determines the strength with which the joint attempts to return to its original position. At 0% it has no effect, at 100% it will hold the child element in place. Springiness gives the joint a natural bounce.
  4. Collide with Connected
    Toggle this to permit or prevent collisions between the child and parent objects when they come together. When this is switched off, the child and parent will pass through each other regardless of their respective collision settings. When switched on, the objects will behave as normal – colliding if they are configured to do so.
  5. Use Limits
    By default, the bolt allows full 360º rotation. When this toggle is activated, you can limit the range of movement (see next tweak for the angle range) and gizmos appear on the gadget to allow you to line up those limits precisely.
  6. Angle Limits Range
    Only available if Use Limits is activated, this tweak allows you to select the maximum range of movement of the child object around the bolt’s pivot. Use the gizmos on the gadget itself to orient and adjust the angle range.
  7. Connector Completion
    This outputs a value from 0 to 1 as the bolt rotates from its initial position to 180º and then it skips to -1 and climbs back to 0 as rotation continues back to the initial position. With this you can test to see what angle the bolt is currently at, or send a signal each time a full turn is made, for example.
  8. Power
    The power input for the bolt retains the connection but disables the outputs. It also reduces the tightness and springiness to 0% as well as turning off any angle limits.
Connectors – common properties (click arrow to reveal)

All connectors are completely invisible in play mode. Even the appearance of the connector in edit mode will depend on the current “Show/Hide” settings (there is a specific option for connectors) or whether you’re working on it now. Similarly the “connector” itself has no physicality. So if you want a connection to appear in your scene, or for objects to bounce off it (for example) you will have to create a separate decorative element in addition to the gadget itself.

As with most connectors it is important to connect the two sculptures in the right order – connect the (larger yellow) gizmo to the parent first, then (the smaller blue gizmo) to the child. Flip Selected ConnectorsIf you ever need a quick way to switch the parent and child relationship, select the connector and click on the “Flip Selected Connectors” icon in the context menu.

When you complete the connection you’ll find that, even in edit mode, the imp can no longer move the child in an unconstrained way – it is limited by the connection. Instead you have to move the parent itself and the child will follow.

If you want to move the child independently, hover the imp tip over the child object and press the triangle button (“Reposition connectors”) on your controller. In this mode the ends of the connector will start glowing and you’ll be able to reposition the child object freely. Press circle to exit this mode.

Reposition connectors

Never connect two sculptures with multiple connectors. Similarly, never make connections in a loop. Such connections are considered invalid in Dreams and will behave unpredictably, if at all (and may even affect your Scene’s performance). When invalid connections are made, the whole connector will turn blue to highlight it (see in the red ovals added to the image here):

Invalid connectors

Connectors only work with sculptures. To connect paintings you have to cheat a little and include an invisible sculpture in a group with the painting. Then the connector can be attached to the group.


Lex Tips

QW Tips

Unless you’re actually mounting a wheel on an axle, it’s usually helpful to think of bolts as being like hinges. They allow rotation in one plane, so in the example of the door it doesn’t matter how high up or low down on the door frame the pivot gizmo is placed (you could put it 100 metres above the door!), the orientation of the pivot gizmo itself is key.

However don’t get tricked into thinking of them too much as hinges – in Dreams, your doors, gates, treasure chest lids and so on only need one bolt, even if you’d have two or more in real life. Dreams will ignore any additional bolts! Obviously, you can sculpt something that looks like it has twelve hinges if you like but only one connector should be used.

Useful Tutorials


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