Questions tagged [drivers]

Questions related to drivers. Drivers are used to control one property with another. Drivers can also use python expressions to give even more possibilities, e.g. *#frame/2* will give the current frame divided by two.

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25
votes
1answer
5k views

Possible to control a Driver from a Group Node input slider?

Sometimes I create Material Groups to be used as appendable reusable assets. Unfortunately sometimes parameters I want to control using a Group Node's slider are not available for routing to a Group ...
16
votes
2answers
3k views

how to copy drivers to multiple Objects?

I want to copy one driver to all selected objects at once, but the "copy to selected" function copies solely the current value of driver, and not the driver itself. Is there a possibility to copy ...
14
votes
3answers
11k views

How can I make a plane always look at camera? [duplicate]

How can I make a plane always look at camera? Like in old videogames, like Doom or Wolfenstein, this kind of software used static images that always looked at the camera, is this possible to make on ...
12
votes
2answers
388 views

How can I rig a cylinder so that when it's rotated its end cap will not penetrate the floor?

I have a default Blender cylinder positioned upright atop a ground plane: How can I rig the cylinder so that can be animated to wiggle/jitter (perhaps procedurally with noise f-curve modifiers on two ...
12
votes
3answers
3k views

How would I change a Cycles material's color using the scale of the object instance it's applied to?

Basically I have a field of spheres that are a bunch of different sizes that use the same material and I want them to be a different color based on their size. I'm using a volumetric shader, so each ...
12
votes
1answer
845 views

Have a video sequence be driven by an audio track

Let me start by stating that I have just recently picked up Blender to use as a Video Editor. Given that my knowledge is limited on this software, I have came across an issue which I can not ...
10
votes
3answers
757 views

Is it possible to add a driver to a vertex position?

I want to add a driver to a vertex' z position. Is this possible? If it is, how? When I try to add a driver, all I get is the option to edit source and edit translation.
9
votes
1answer
9k views

Python auto-execution disabled error [duplicate]

I'm getting this error often, and I'm fairly new to blender and I'm not sure if this is the same thing as the Auto-run disabled issue, but I can't finish my project with this error in the way. It ...
9
votes
1answer
348 views

Essentially, what are drivers?

Okay, so I'm a relatively new user of Blender. I've delved into most of Blender already, including the Graph Editor and F-curves, but not the Dope Sheet or Drivers. I'm planning to get into what the ...
8
votes
2answers
5k views

How do I stick an object to another objects vertex?

I just created a plane and added a wave modifier to it, to simply make it look like something fluid. Now, I have an Object that I want to place on the surface of this fluid plane. But how do I do that?...
8
votes
1answer
563 views

Detect light amount on surface?

Is there a way to detect amount of light affecting some surface and use this value in a driver?
8
votes
1answer
1k views

Why can't I “Copy a Data Path”?

I'm sorry this question won't be very clear but i really can't understand why i can't "Copy Data Path". I can't even select him although i corretly paste data before. What could be wrong??
7
votes
1answer
2k views

Why are my drivers not updating instantly?

So I have a bone driving the 'scale' property of another bone, along with the value of a shape key. If move the driver bone, it works fine, but right click to cancel, the scale of the driven bone ...
7
votes
1answer
365 views

Can drivers span more than one line?

Is it possible to write Multi-line drivers? As I understand it, drivers just assign the given statement to a variable, so you couldn't have _expressions (which don't evaluate to anything) in there. Is ...
7
votes
3answers
1k views

How to drive text based off of a value

How can I drive the content of a text object by a value box such as the samples slider? I want to be able to change the value here: And have the value show up automatically on this text object, ...
7
votes
1answer
558 views

Is Dynamic shutter speed in Sampled Motion Blur possible?

I have a single object spinning (at varying speeds controlled by F-curves) along two axes. The effect I'm going for turns out best if I can vary the Shutter in Sampled Motion Blur for every frame, ...
7
votes
1answer
2k views

Using a scripted expression driver to combine two angles

I am trying to use a driver with a scripted expression to place an object's rotation in between the rotation of two other angle-measuring objects. So there are objects I've labeled ...
7
votes
1answer
465 views

Drive Objects Rotation depending on state of other objects sin and cos value

I started to get into Drives. I want one cube(green) to rotate 90° whenever the other cube(red) is doing it's last 90° turn on the way to the full 360°. Now i've come up with following Logic depending ...
7
votes
1answer
2k views

How can I get a random number that is constant per object in a driver?

I would like a driver that gives different result when duplicating the object but stays constant on frame update, transformations, etc... noise.random gets updated on frame change. I thought about ...
6
votes
2answers
5k views

Adding Other types of Custom Properties

I'm starting to use the amazing, yet simple to use Blender Drivers: I'm looking for a way to add other Types of Custom Properties than the default floats. For instance: Color, Vector, String, ...
6
votes
2answers
1k views

I want to mix Cycles shaders based on self shadow

I have a sphere (world) that I want to reveal the night lights on. I can use a normal node and manually rotate the DOT product, then I use this as a factor mix between Day time shader and Night time ...
6
votes
1answer
3k views

Is it possible to put an if statement into the scripted expression of a driver?

If the y location of a certain object is greater than 0, I want to add a fixed amount to another object's driven channel. How do I achieve that?
6
votes
1answer
2k views

Get π in python scripted expression for a driver?

Get π in python scripted expression for a driver?
6
votes
1answer
773 views

Establish a variable inside a driver expression

I'm quite new to python and drivers. I'm writing a rather complicated scripted expression inside the driver-area and I need to repeatedly use a long number sequence. Would it be possible to first ...
6
votes
2answers
2k views

How to apply a driver to rotate an object around a custom orientation?

I'd like the drive shaft to rotate at four times the rate of my wheels. I have an animation that spins the wheels, using parent empties; and I have custom orientations on the pieces of my drive shaft, ...
6
votes
3answers
2k views

How can a blender driver python script access scene properties like FPS?

I would like to be able to access properties of the current scene such as render.fps, frame_start, and frame_end from within a python driver script. I have some data that is defined in terms of ...
6
votes
2answers
742 views

Check if a property is animated or has a driver

Using python, how can I check to see if some property (like context.object.location) has any keyframes, or has a driver attached?
6
votes
1answer
1k views

Relative reference to object property in material driver?

Is it possible to get a value such as the dimensions (object.dimensions) of an object in the material node editor, without referencing a specific object? In other ...
5
votes
4answers
650 views

Drive shape key based on relative camera orientation?

Let's say (for the sake of simplicity) that this cube with two blue sides is my character... and the shape key in question raises a few vertices on top. Whenever the camera views either Blue side, I'...
5
votes
1answer
3k views

Bake driver to keyframes

Can you bake the animation created from a driver to keyframes?
5
votes
1answer
462 views

How to access data related to individual particles?

I would like to create simple drivers to manipulate individual data points for things like Particles and Array Modifiers. Just as an example, when I create a particle system, if I create a driver for ...
5
votes
1answer
2k views

Is there a caveat to using drivers on node properties?

So, it seems to be a trivial matter to use a different seed on each frame (it looks nicer in animations). I.e. type "#frame" into the seed value and viola! You now have a driver. In fact, if I turn on ...
5
votes
1answer
1k views

Python script to print tooltip value when mouse is over a property

I want to get the tooltip value of a property when the mouse is over it (after pressing a shortcut), like the X location of an object or another value that can be animated in the scene. In specific, ...
5
votes
1answer
2k views

Other possible expressions like #frame

I have learned a few minutes ago that you can type # into a numbutton to create a driver. So far the only value I know is frame. While this works nicely, it's still a bit limiting. What are the other ...
5
votes
1answer
806 views

making a ball roll with drivers

I want to "rig" a ball, so that it looks like it's rolling on the ground as I move it around. So far I've parented the ball to an empty and set up drivers for the X and Y rotation, so that the ball ...
5
votes
1answer
787 views

Is it possible to use timeline markers for driver expression?

I want to use timeline markers for driver expression, is it possible? And is it need to be added to bpy.app.driver_namespace for quick driver add like #frame? If ...
5
votes
0answers
32 views

Calculating position difference in a driver

Suppose I have an object, that I move from A to B (by pressing the G button) on the XY plane. I want to automatically orient it, so it always faces the direction of the movement. Furthermore, I want ...
4
votes
2answers
11k views

What does 'Autorun disabled' statement mean?

Could someone explain me what does this statement mean and what option should I click when it pops up?
4
votes
1answer
512 views

Rotate a Cube on a Plane Using Drivers

This is a simplified example which I wish to apply to a more complicated animation situation. I have a cube, that is 1x1x1 in size, origin at the centre and is located at (0,0,0). It sits atop a ...
4
votes
1answer
3k views

How to put together a driver with python

I'm trying to write a script to create the beginnings of a music visualizer but I'm having a hard time creating drivers to do it. My basic game plan is this: Calculate frequencies and step sizes For ...
4
votes
4answers
2k views

How do I create a driver with a random value and apply that driver to multiple objects?

I have a few rocks in my scene. Lets say the scene is in space and I want to add some random rotation to the rocks. Since there are a few of them, I don#t want to go to every rocks properties and ...
4
votes
2answers
847 views

Driver on material not updating

Sorry for the noise... My previous question was answered, and I've fixed what I was doing wrong; but only so far as to allow me to phrase a new question, as my original problem still exists. :/ I am ...
4
votes
1answer
656 views

How do I set up a driver to drive a node value with a node group input? [duplicate]

I'm having trouble figuring out how to link one value to another via a driver. Here's what I'm trying to do: I'm making my own node group and I want to bypass having to tab into the group to change ...
4
votes
1answer
2k views

Can we execute custom Python functions from driver expressions?

I have a simple function that I'd like to call from a driver Python expression. I've run the script to define the function, but it doesn't seem to be accessible from the driver expression. ...
4
votes
1answer
1k views

How can I set a Shape Key value to be a driver's variable?

I want a Shape Key's value to be driven by another shape key. But I don't know how to add a shape key value as a variable into a driver. I've selected single property and tried with Object or Mesh ...
4
votes
1answer
1k views

Driver is not working as expected

I have put a driver in the z rotation of an empty and made the variable a single property, where the path is the count in the array modifier. My expression is ...
4
votes
1answer
800 views

add driver for a shapekey via python?

how can i add a driver for a shapekey via python? shape_keys.animation_data.driver_button_add(True) or ...
4
votes
1answer
1k views

How to correctly drive a normal node with lamp rotation?

I'm trying to use drivers to allow a lamp rotation to dictate the direction of my normal node. The problem seems to be that the sun can rotate from 0-360 degrees, but the driver has a limit of 0-90 ...
4
votes
1answer
2k views

How to add a driver via python?

I want to add a driver to the Z location of an object via python. After reading the docs and this question, I would guess something like this: ...
4
votes
1answer
250 views

Driver based on Render Layer

I want to drive a property in a Cycles material based on the current Render Layer or Scene being rendered. Is there any such property? If not, is this something that could be made as an addon, or is ...

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