RBF Nodes

New version

Please read the version 1.0.0 release notes below if you have used RBF Nodes before

 

RBF Nodes is a node-based RBF solver for Blender. It allows to drive multiple properties with multiple driver values.

RBF stands for Radial Basis Function and is used to approximate or interpolate a given set of values at any defined sample point. RBFs have a wide range of applications and can be very helpful when regular ways of driving values fail in 3D animation. It basically allows the user to interpolate multiple values based on a set of sample values, or poses which are defined by the artist in advance. For standard drivers, such multi-value interpolation is not easily, or even impossible to achieve. Like, a driver in Blender can have multiple input values but only one output target. RBFs can solve multiple output values based on multiple input values.

RBF Nodes has its own node tree to make it independent from any modes and panels. Even though RBFs are commonly used for rigging to drive certain deformation effects it would be a waste to limit it to armatures only. Therefore, you can use it with objects, armatures, shaders and geometry nodes, which makes it very versatile.

The above video is a quick rundown of the workflow. For a more in-depth explanation see the tutorial section below.

Important Note:

The add-on is still in it’s testing phase and it’s possible that certain object and property combinations are not yet functional or supported.
If you hit a limitation or issue feel free to contact us. We’ll see what we can do.

compatibility

Blender 3.1.0 and later

version

1.2.0
2024-06-04

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tutorial

Introduction: 0:03 min
Node Tree: 0:58 min
Basic Setup: 1:27 min
Inputs: 2:50 min
Outputs: 3:35 min
Poses: 5:14 min
Activation: 6:35 min
Limitations: 8:22 min

installation

  1. Download the add-on as a ZIP-file.
  2. Open the Blender Preferences window by choosing Edit > Preferences…
  3. Select the Add-ons tab.
  4. Press Install… and select the downloaded ZIP file. After successful installation the add-on should be visible in the list.
  5. Activate the add-on.

usage

The RBF Nodes editor can be found in Editors > RBF Nodes Editor.

A documentation hasn’t been written yet but will be added once the add-on is passed the testing stage.

Until then please refer to the video tutorial above.

limitations

  1. In order to play back or render a scene containing RBF nodes it’s mandatory that the add-on is installed. Since Blender doesn’t offer any outside access to the dependency graph in it’s current state, the evaluation of the RBF nodes needs to get triggered through the add-on. If the add-on is not available the nodes don’t know when to evaluate.
  2. Even though the virtual number of input and output values is unlimited there is an internal limit due to technical limitations of Blender. Currently a pose can store 1024 values which are shared amongst driver and driven values. If this value is not sufficient it can be easily expanded on demand by your local coding mate.

version 1.0.0 important changes

Breaking Changes


Existing RBF setups created with previous versions are not directly compatible with the new release.
However, when opening files containing obsolete setups a message is displayed informing about the incompatibility. Also, no controls are accessible in the side panel of the RBF Nodes editor.

Still, older setups can be converted and updated to work with the current version of RBF Nodes.
This is done by deactivating the RBF setup and activating it again.

Use the following steps to convert an existing RBF setup to match the new version:

  1. Press Reset RBF in the RBF editor’s side panel.
  2. Press Activate RBF in the same panel.

 

Important Changes


Locked Nodes
When activating the RBF setup all input and output nodes are now locked to prevent editing. This is meant as a guide since setting up properties should always be done in advance and before defining poses.

Shape Keys
When poses already exist it’s usually not possible to add input or output properties because all properties need to exist in all poses and have to be different. Also, there needs to be a rest pose.
If a new property is added and a pose is set there is no way to tell what the rest pose values of this property is.
The only exception are shape keys, and this has been added to the current version.
When a new shape key property is added after poses already exist it can be assumed when creating a new pose that the current shape key value should only be used for this pose and be at zero for all other poses.

 

Other Changes

  • Updated node names to differentiate between inputs and outputs.
  • Improved interpolation for quaternion-based rotation.
  • Improved error messages.

 

Fixes

  • RBF calculation is offset by one frame.
  • Quaternion output depends on the Euler axis selection.
  • Shape key drivers remain when resetting the RBF.
  • Shape key data block names other than the default are not respected.