|Name of gadget||Motor Bolt|
|Number of Tweak pages||1 (of 3 rotational connector types)|
|Last updated||07 August 2019 [EA v1.07]|
The Motor Bolt is a powered connector that can spin one object relative to another. It is virtually identical to the Bolt connector, but with the addition of a turning force (and associated tweaks) that allow you to spin the moving part (the “child”) under its own power. Naturally this makes it a great contender for clockwork cogs and car wheels and electric fans, but the centre of rotation need not be anywhere near the object it is rotating – it could equally be used to make a moon orbit a planet (assuming a circular orbit) or a camera around an interesting focus.
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, which will cause the motor to oscillate backwards and forwards between two limits (somewhat like a pendulum, albeit at constant speed) 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 Motor Bolt is almost indistinguishable from the Bolt – with just an extra faint line spinning about the pivot to indicate the speed and direction of its intended motion.
As well as its motor settings, it has a ‘connector position’ input that can be used to specify the angle to which you want the bolt to turn – so instead of revolving in a circle, it can be used to point something at a specific angle.
Example Tutorial (adapted from Media Molecule)
- Let’s make a windmill. Go to sculpt mode.
- Create a large block to represent the main building of the windmill.
- Start new sculpt and create another block to represent the windmill’s sails – how detailed you make this is up to you – for this example, a narrow plank would suffice.
- Return to assembly mode.
- Align the sail in a suitable place against the windmill’s body if necessary.
- Get a motor bolt from the gadgets menu.
- Connect the parent gizmo to the body of the windmill.
- Connect the child gizmo to the sail.
- A pink pivot gizmo appears between the two. Drag this into place in line with your sculpts and rotate it so its axis passes perpendicularly through the centre of your sail.
- Hopefully, the connector should indicate the bolt turning in a circular path in the same vertical plane as your sail. Start time and see the sail turn about the pivot axis you’ve set up!
- If you need to adjust the position of the pivot, just rewind time, grab it and make the changes you need.
- 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.
This setting determines the ease with which the bolt resists deflection by external forces. At 0%, it can be easily pushed around (though how much will depend on Strength ). At 100% it will mostly ignore external forces.
- 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.
- Cycles Per Minute
How fast do you want the motor to turn? Set the value here in terms of revolutions per minute. The default of 60 is equivalent to one complete revolution per second, 1 Hz.
This setting is used to set the strength of the motor, its ability to push against any other interference with rotation. At 0% it is incapable of turning at all and low values can behave quite erratically (it struggles to turn itself)! At 100% it will probably force any movable obstruction out of its way as it turns.
- Reverse Direction
Viewed downwards from the parent to the pivot gizmo, the motor bolt turns in a clockwise direction. Use this toggle to reverse direction. (You can achieve the same effect by setting a “negative” cycles per minute .)
- Use Limits
By default, the motor 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. When the angle is limited, the motor bolt’s action changes so it swings back and forth between its limits instead of spinning in just one direction.
- 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. Note that this tweak only changes the angle range. You may need to orient this with the gizmos on the gadget itself.
- Connector Position
This tweak can accept a numeric value to tell the motor bolt to rotate to a specific angle. Think of the number as the fraction of a turn. A value of 0 sets the bolt at its initial position; a value of 0.25 will be a quarter revolution, 90º. Thus the mapping of input to angle increases until at an input of 1, the bolt will have come back to its starting position again. If this input signal is unchanging, the motor bolt will effectively stop moving, though this of course may depend on external forces, the bolt’s tightness and strength.
- 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.
The power input for the motor bolt retains the connection but disables the outputs. It also reduces the strength and tightness to 0% as well as turning off any angle limits. Naturally, it stops spinning under its own power, though it can still be turned by external forces.
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. If 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.
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):
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.