olliebrown / blender-origami-fold Goto Github PK

Add on for Blender 2.90+ that automates creation of armatures for animating folding paper.

License: MIT License

Python 100.00%

blender-origami-fold's Introduction

Origami Fold Blender Add-on

This is a simple add-on for Blender 2.90+ that adds some commands to the mesh 'edge' sub-menu for creating armatures that simulate paper folding around an edge.

Presently you can create armatures that:

Fold the "left" side of the edge
Fold the "right" side of the edge
Fold both sides simultaneously (like 'mountain' or 'valley' folds)
- Just a pre-linked left & right fold

Other features available:

Link any new fold to the one previously created so they fold at the same time
Create new folds as parents of previously created folds
- Left parents to left, right parents to right

Possible future features:

Bevel edge to give fold some thickness
More than 1 axis of symmetry (e.g. more than left vs right)
Think about IK for squash and inside-reverse folds
Support for other advanced 3d fold types

Installation

Click 'code -> download zip' above to download the add-on zip
Extract the one folder inside, rename it to 'OrigamiFold', then re-zip it
- Note: I will eventually post releases that avoid this step
In Blender, open the preferences pane
Click 'Add-ons' at the left then 'Install..' near the top
Select the Origamifold.zip file you created
Locate 'Mesh: Origami fold' in the list and enable it

How it Works

The concept behind this add-on was largely inspired by the following Youtube Video:

How to make animation of paper plane in Blender

I automate placement of bones and avoid multiple armatures by:

Using vector math to compute orientations that are perpendicular to the edge
Painting weights automatically using an internal plane equation with the edge and the paper's surface normal
- Some vertex weighting is not needed due to parented bones
If a bone moves an edge containing another bone, it becomes that bone's parent
- This avoids needing multiple armatures

Basic Workflow (for very simple models like paper planes)

Here's a basic workflow to create an animation similar to the one above:

Prepare your paper:

Create a plane/quad aligned with XY-plane of the proper dimensions.
Cut edges into the plane with the knife or subdivision tool to match the crease pattern of your target model.
Ensure there is only one vertex at each edge endpoint (merge duplicates)

Create your folds:

Select all edges segments (along a single fold)
In the 'edge' menu (View3D, edit mode) select Origami Fold
Add the fold type desired

Tips:

Think about dependencies as you create your folds
- If two folds are a mirror image, consider using the 'linked' feature
- If fold will move the bone of one coming later, make the LATER one first and then use the 'parent' feature
The order you create folds matters when using the 'linked' and 'parent' features

Examples

(coming soon)

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blender-origami-fold's Issues

Paper Thickness

Explore paper thickness options. The 'solidify' modifier seems like low-hanging fruit but it does not always play well with extreme folds, bevel modifiers, and other oddities that might be commonly needed.

Can't find the menu to use it

After installing the addon I prepared my paper, added an armature and parented the paper to it. When in edit mode, I don't find any menu regarding the addon though...

Support Fold radius (note, not paper thickness)

Real folds have a radius to them and the folded portion ends up sitting on top of the paper it meets up to (not in line with it). We need to explore adding some radius to the fold via the 'bevel' modifier and careful bone placement and vertex weights.

The original video that inspired this plugin (see readme for link) does this but it requires a lot of hand tweaking and seems to yield only moderately satisfying results without a lot of intervention. Want to explore how fool-proof we can make this and how it might also interact with a 'solidify' modifier to give the paper some thickness.

Intelligently support 'Undo'

Undoing the creation of folds creates an inconsistent state for the plugin. Need to explore Blender's options for rigorously defining how to 'undo' a python operator and implement this properly.

This is related to issue #1 and might be mitigated by changes there.

Dual-Fold without Parenting throws python error

The 'asParent' parameter is required but missing. Easy fix.

Expose Parameters for Fold Operator

Research how to have the little parameter box pop up after an operator that exposes ways to customize the operator itself. This would allow the user to adjust things like:

Fold direction (see issue #2)
Parenting and Linking
Bevel thickness and offset as part of fold radius (see issue #6)

This would also make the operators more consistent with Blender's built-in operators.

Probably need to consider the undo issues (#4) as well, as I suspect change the parameters after the operator is run would in fact cause a quick undo and redo to fire. Need to research how that works as well.

Internal Fold Count and Bone List can get out of sync

The list of folds and their associated bone names stored in the python script can get stale. It will hold onto the names of bones even if they have been deleted. It also seems to occasionally 'count' the folds incorrectly.

Need to take a different approach. Consider:

Name armature from the paper object name instead of just 'Fold'
Don't keep a list of bone names, instead search for them every time they are needed
- Alternatively, always audit the list to ensure the bones exist still before using
Determine which bones to parent based on if they currently have a parent or not (don't just use list)

Support more lines of symmetry

Right now, only one line of symmetry is supported for linking folds (the Y-axis, left/right symmetry). We should expand this to not be relative to arbitrary things (like 'left' and 'right') and include more possibilities (4 lines, maybe 8 if possible).

Things to consider:

4 possibilities is straightforward: +X, -X, +Y, -Y
More than 4, what should we name the lines:
- Angle degrees (where is 0, CW or CCW)
- Clock-face numbers (no perfect 45 without using minutes or fractions)
Could this just be reasonably automated so they don't need names, detect what way the edge tangent is pointing?
- How do we know when it is backward and needs to be flipped (a common issue)?
  - Pick the side with the fewest vertices (e.g minimize the surface area of the folding part)
  - Utilize winding of neighboring faces to make it unambiguous
- Having the user tell us via names avoids that ambiguity but burdens the user