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.

153 questions with no upvoted or accepted answers
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69 views

sending Data or Values to linked Objects in Blender 2.80 / 2.81

I work a lot with linked data and library objects or linked collections. Is it possible to send values or variables between the different hierachical structures ? So for example: SCENEFILE (var = ...
4
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1answer
107 views

Maintain equal rotation on multiple objects

I am making a model with gears. I want to be able to turn any gear and have the others follow. Using constraints or drives only one gear will rotate (and the other will follow). Is there anything I ...
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241 views

Level of Detail of Particles System?

First, the GIF above is a 60-frame sequence with a 1080x1920 size that uses a freestyle to render the outline. This scene is a lot of polygon counts using the full shot model because the characters ...
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0answers
20 views

When a Driver is being evaluated are the final positions of objects finished evaluating?

When a Driver is being evaluated are the final positions of objects finished evaluating? Does the Dependency Graph take into account references made in a Driver for a topological sort? The Blender ...
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0answers
459 views

Blender to Unity, keep drivers

I'm trying to teach myself blender and unity, and I'm currently building a simple tank. I've made the wheels and threads move correctly with the body of the tank using drivers, but when importing the ...
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2answers
1k views

How to get a Material property driver to update properly (2.78)?

After watching this excellent tutorial (https://vimeo.com/40389198) I thought "what ho, this is just what I was looking for, I can make random variations in mass-produced objects!" So I started trying ...
3
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1answer
538 views

Blender game engine, shape key driver

i want to create a character with differents shape keys for modify things like if the character is big or small, if he smile or not... and i want to modify values or shapes on blender game engine. To ...
3
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1answer
418 views

Linked Objects, Drivers and Animation of custom Properties

I have created an Object with some Shape Keys. To simplify the planned Animation, I have created four custom Properties on that object and connected some drivers, so that the change of one Property ...
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0answers
339 views

Use value of node output for driver

Situation: I have an Object that rotates (keyframed). I use Nodes and Drivers to set the objects color to blue within the first quarter of one whole rotation (90°) and red for the rest (270°). That is ...
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0answers
260 views

How rely the orientation of an object facing the camera to the side it's looked at?

Use case / goal See the images below. The green plane is attached to a target, the grey sphere, and is facing the camera, but its orientation change depending on witch side of the target the camera ...
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0answers
28 views

Define object thickness with curve

I'm modeling a heart-shaped cookie cutter, and I'd like its cross section to be thicker near the top and come close to a point at the bottom. The heart is a Bezier curve with a mirror modifier, ...
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0answers
87 views

How do you make a seamless IK > FK > IK switch using drivers?

Is there a way to have a seamless IK, to FK, to IK, to FK, etc... kind of slider? I have seen it to be done in riggify but it uses a python script that only works with that armature and doesnt look ...
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0answers
37 views

One shared material with different custom property for each object

I'm trying to procedurally generate a scene with several objects (cubes for now!) sharing a single material, but appearing and fading out at different times. So far, I have been able to place the ...
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0answers
191 views

Use self and the slow python expression

In putting together an answer to Changing Multiple Influences Simultaneously I came across the Slow python script warning in the drivers editor Using a set up as outlined here driving a pose bone's ...
2
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0answers
213 views

How to make abs() give correct result for negative numbers?

I am trying to use the simple absolute function abs() in Expression frame for a driver, but it won't work. I've tried to put it in long sentences, or even just typing abs(-1) but the negative still ...
2
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1answer
42 views

Pause in relationships and constraints

I want to talk about relationships between (for example) two bones. There are two bones (A and B), bone B has a Cconstraint, bone A is the target of that Constraint. Let the Constraint be "Child Of". ...
2
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0answers
58 views

How to drive the color in node editor by the color of the light?

I want to control the color in the node editor by light color. After trying it myself, I guess I should probably get the RNA properties and enter it in the driver editor in the correct way. I ...
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0answers
93 views

The second emitter does not emit particles in the correct way

I'm trying to create a traffic simulation using the blender particle systems with different model of cars. The enviroment consists of a two-lane road. I want the cars crossing the two lanes in ...
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0answers
97 views

Can I “mute” all f-curve drivers in a single click?

I often need to review the results of my face-rig's expression animation transitions. However while drivers are connected to the bones the animation data does not change the bone's transform when the ...
2
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1answer
191 views

Help with implementing Shape Key Drivers

I was wondering if anyone could help me out with figuring out how to use Shape Key Drivers for the model that I've been working on for quite a while. Basically, I need my model's head to be able to ...
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0answers
31 views

Is there an equivalent of After Effect's “valueAtTime()” for drivers?

In After Effects you are allowed to use Expressions very similar to blender's drivers. In a very simple fashion you can get a property's value based on a given time like so: ...
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0answers
60 views

Is there a way to put a driver on Emission Count in a Hair Particle system?

I am working on a way to populate random details along a single edge (like windows doors, garage doors, ..etc), in an attempt to create semi procedural buildings. So far I have found that using a hair ...
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0answers
59 views

How to associate Driver with scene active camera?

I've got two cameras in my scene. When they are switching via timeline markers, Driver which is based on distance between some object and camera1 goes crazy, because at this point I am filming with ...
2
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0answers
304 views

Using Python to add driver to cycles material node properly

I've been working with an audio-driven animation and discovered that you cannot apply a driver directly to an input field on a material node. Rather you need to navigate through the Datablock to the ...
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0answers
108 views

Get a Variable from One Driver’s Script and Use It's Value in Another Driver’s Script

I have an issue where I need to be able to access a variable from one script inside of another script. Here is a short version of the code I’m working with: ...
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0answers
1k views

Questions about driver scripted expression

At the moment driver scripted expression is giving me a hard time and hopefully someone can help to figure out how does it work. Here are the questions. How can this expression be written in the ...
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0answers
57 views

How to acess the actual bone rotation?

I want to write a operator that adds a driver to a shapekey. so the shape key can be controlled by a bone. the main idea is that the current position of the bone becomes the value 1 for the shape key,...
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0answers
159 views

Export rigged model (with drivers) to maya

I want to export my rigged model in fbx format but it wont include my drivers and constraints. Is there a format which will "keep" my settings? I want it to be able to be opened in maya or other 3d ...
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0answers
49 views

Use of dynamic paint to influence transform settings

Can Dynamic Paint be used as a factor for a driver? I want to automaticly shake an object when hit by, for example a particle. The easiest way to register an impact accuratly seams to be dynamic paint....
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0answers
315 views

Is it possible to access the angular velocity of an object from a driver?

Is it possible to access the angular velocity of an object from a driver script? I know how to do this in BGE but this is for an animation. Currently I am saving the current rotation for use in the ...
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0answers
372 views

Drivers not working when running blender in the background from command line

I am trying to animate a Blender file from the command line that is using a couple of Python functions for Drivers. However, the command gives the following error, and consequently does not perform ...
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0answers
654 views

Degrees, euler quaternion?

I am sorry, this is probably very simple question related more to maths than blender itself, but I really have no idea what number respresents what angle. I have a feeling that it might be somehow ...
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0answers
326 views

Driving Shape Keys by proximity of an Empty

How can shape keys be driven by an Empty's coordinates relative to the object? I'm guessing this can be done with a Python expression but not sure how to write it. Also, how might we specify the ...
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0answers
40 views

A property that is different during rendering and during preview

I want some properties, like the Factor value in a Mix Shader node, be controlled by whether Blender is currently rendering or not - so that some things would look different in the Preview and in ...
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18 views

Set Keyframes for Drivers

I'm trying to animate some Gears with Drivers. With the Expression '(bpy.context.scene.frame_current)/10' it works very well. The gears are rotating from begin to end of the frame range, but I would ...
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0answers
22 views

Blender 2.8, Getting Script to Update a Driver

I have a for loop (A) that is updating a Custom Property (B) that is a driver for a Cube's X-location (C) which is supposed to update the Cube's location (D) and Export each incremental change to a ....
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18 views

How to rig a BB-8 Model?

I want to make a rig for this BB-8 unit so that when it moves on X or Y axis it can rotate automatically even if it moves on both axis (on diagonal direction) most of tutrorials i saw works in case it ...
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0answers
20 views

Blender 2.80: Getting min() / max() right in an expression for a driver

If the scripted expression of my driver uses "min( var, 1.0 )", and "(x) var" is set and the y-position of an armatures bone is used as data source, everything works as expected: The drivers value ...
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0answers
27 views

Accelerating a looped animation over time

I've got a looping animation set up for a ground plane so it looks like there's motion (kind of like a repeating conveyor belt), but I'd like to make it accelerate linearly over time. Here's a preview ...
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0answers
27 views

Object with driver issue when rotating around Z- and X-axis

My object (a mechanical arm) is Clamped To a curve. I am using a driver to move this mechanical arm around the curve. When rotating this curve around the z-axis or x-axis, the entire arm starts ...
1
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1answer
55 views

Boid Particles - How To Use Fighting/Battle Information In Animation (Fighting Ants)

I am experimenting with boid particles and I have set up an ant fight simulation, where there are two enemy boid systems emitted from different areas (vertex groups) of a plane. "Allow Land" is ...
1
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1answer
32 views

Custom float property used in a driver need manual UI modification to work

I'm currently creating some script to automate a cloth rig setup. In the process I'm adding a custom float property to an empty and use it in a driver. It's a concept I wish to reuse for other ...
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0answers
251 views

Shape key and driver Problems Blender 2.8

I'm rigging a character and I would like to fix spots that weight painting won't fix with shape keys. But assigning bone as a driver doesn't do anything. It's controlled by an IK bone and doesn't seem ...
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0answers
12 views

Retrieving the Material from a NodeTree

For a driver scripted expression I want the name of the material for a node input value. It's an emission node and I want to make the following scripted expression for the emission strength: ...
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0answers
103 views

Blender 2.8 eevee - Is there a limit for image nodes quantity in a material?

I'm making a customizable character with switchable skin via driver. It is organized by 9 types of skin and each type with 3 make-up as you can see in the 1st image. A total of 27 images. So the ...
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0answers
61 views

Better to add extra bones before or after generate rig

Im using rigify addon and plan to add some shape keys and some drivers later on like for facial expressions and talking. Is it a good idea to add those driver bones to the metarig before I click ...
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0answers
42 views

Spline IK gets disabled on random frames (new depsgraph) / bone drivers get updated too late

I’m trying to get my Spline IK working. It’s behaving the way I want to, except for random frames where it looks like the Spline IK doesn’t get applied to the bone chain and the bones go back to their ...
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0answers
78 views

Using drivers to animate the opacity of a strip in VSE

my final goal would be to use Blender VSE for video editing, where I'd overlay a strip over a background video when there is sound in the corresponding audio track, so basically, the volume in an ...
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0answers
90 views

Using a curve's calc_length() method in a driver expression?

Recently I've dipped my toes into Blender's drivers & expression system. I'm trying to scale a road to exactly fit the length of the curve it's following. I came across this post of two years ...
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0answers
108 views

Driver not updating when rendering animation

Have you ever experienced such an issue? Driver not updating when rendering animation, but updating when single images are being rendered one by one? Case description: I created empty, linked to a ...