The Drivers Editor allows users to drive one property with another.See Drivers and F-Curves.
Main Region¶
The main view allows you to view and edit Driver F-curves.An F-curve has several key parts:
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The curve defines the relationship between two properties:The current (driven) property (Y axis) and the driver (X axis).
See F-Curves.
Each point on the driver curve has a handle that helps determine the relationship between the two values.They can be selected and modified to change the shape of the curve.
See Handle Types for more information.
See also
See F-Curves for more info.
Navigation¶
As with most editors, you can:
- Pan MMB
- Pan the view vertically (values) or horizontally (time) with click and drag MMB.
- Zoom Wheel
- Zoom in and out with the mouse wheel.
- Scale View Ctrl-MMB
- Scale the view vertically or horizontally.
- View All (Frame) Home
- Fit the curve in the available space.
In addition, you can also use the scrollbars to pan and zoom the view.
Header¶
View Controls¶
Normalize curves so the maximum and minimum points equal 1.0 and -1.0 respectively.
- Auto
- Automatically recalculate curve normalization on every curve edit.Disabling this setting may be useful to prevent curves from jumping after tweaking.
Object data-blocks appear in alphabetical order, so that it is easier to find where they occur(as well as helping to keep the animation of related objects together).
This option may affect the playback speed for heavy scenes.
Curve Controls¶
Pivot point for rotation.
- Bounding Box Center
- Center of the selected curve handles.
- 2D Cursor
- Center of the 2D Cursor. Playhead + Cursor.
- Individual Centers
- Rotate the selected curve handles.
Auto snap the curve handles when editing.
- No Auto-Snap
- Frame Step
- Second Step
- Nearest Frame
- Nearest Second
- Nearest Marker
There is one moment in node tree, created to separate the sides of the planet model by “day” and “night” – when the position of light source changes its new coordinates every time needs to re-specify manually in Value nodes. It is very inconvenient while setting the scene. To eliminate this fault Blender “drivers” system can be used.
Lets make a simple scene showing the separation of the planet sides. Create a planet (sphere). The light source (plane) locate at 5,0,0. Create a material with “day” and “night” separation, append it to planet.
Simplify nodes tree packing what we do not need during setup into the groups.
- Select the desired nodes
- ctrl+G
![Drivers Drivers](/uploads/1/2/5/8/125840819/760903685.png)
There are only Value nodes with the coordinates of the light source outside groups. We will setup drivers to them.
Drivers – a Blender mechanism that uses properties, numbers, transformations, and scripts, to control the values of properties. In simple – drivers proceed dependences some object properties from properties of other objects. In this case we need to associate values from Value nodes in planet material with lighting plane coordinates.
To install driver to the X lighting source coordinate Value node:
- Click the right mouse button on the numerical value of Value node for X coordinate
- Select Add Driver
The value will painted in purple.
- Open the Graph Editor
- In its menu set Mode to Drivers
If node with driver is selected, the Graph Editor displays the name and path of the controlled value, curve and Drivers tab in the N-bar.
Pay attention to Drivers tab. First we need to configure driver type, regulated with Type parameter. Driver type is a formula that calculates driver output value. There are several variants:
- Maximum Value
- Minimum Value
- Scripted Expression – output value calculates by the expression on the scripting language
- Sum Values
- Average Values
These formulas, except Scripted Expression, are needed in order to handle multiple input values by driver. For example, if single object’s position depends on the positions of several other objects. Through a driver that handles multiple input location values, one result can be calculated. A Scripted Expression type you can set to get the output values from scripting language Pithon – this type is used, if other types are not enough.
In our case, we have one input value – X coordinate of the light source. Therefore, we can choose any type of driver, except Scripted Expression. For example – Sum Values. The sum of single number always equal to the same number.
- In Graph Editor
- In N-panel
- Drivers tab
- set Type to Sum Values
- Drivers tab
- In N-panel
Next, pay attention to created by default variable named “var”. This variable is the actual input value, which handles by driver. It also has a type:
- Distance – the distance between two objects
- Rotation Difference – the difference between the rotation angles of two objects
- Transform Channel – location data of the object
- Single Property – value of any object parameter, defined by the scripting language
All types, except Single Property, are used to obtain values that required more often. Like driver type, Single Property can be used to get any value of the object using the Pithon language. In our case we need to get the X coordinate of the light source. Therefore, we select the Transform Channel type.
In the Object/Bone field specify the object – the source of the input value. In our case – a light plane. It is necessary to specify the desired type of coordinate:
- In Graph Editor
- In N-panel
- Drivers tab
- “var” variable
- Set Type to Transform Channel
- In the Object/Bone field specify the light plane
- Set Type to X Location
- click the Update Dependencies – upgrade the relationship, ie, apply the specified values
- “var” variable
- Drivers tab
- In N-panel
Driver that connects the X coordinate of the light source and the Value node for this coordinate in the planet node tree is created and configured. Now if we try to move the light plane by its X coordinate from different sides of the planet, we can see that “day” and “night” textures changes their places.
In the same way we need to create and configure the two other drivers for the two remaining coordinates.
- Click the right mouse button on the numerical value of Value node for Y coordinate
- Add Driver
- Select node
- In Graph Editor
- In Drivers tab
- set Type to Sum Values
- For “var” variable
- set Type to Transform Channel
- In the Object/Bone field specify the light plane
- set Type to Y Location
- Press the Update Dependencies
- In Drivers tab
- In Graph Editor
- Click the right mouse button on the numerical value of Value node for Z coordinate
- Add Driver
- Select node
- In Graph Editor
- In Drivers tab
- set Type to Sum Values
- For “var” variable
- set Type to Transform Channel
- In the Object/Bone field specify the light plane
- set Type to Z Location
- Press the Update Dependencies
- In Drivers tab
- In Graph Editor
All three drivers for three coordinates of the light source are configured. Now we can move the light plane to any place – “day” and “night” textures of the planet always will be mapped correctly.