Threadify Detangle 1.0

Bola Studio

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An HDA to prevent curves from intersecting each other in Houdini.

This node is part of the Threadify pipeline to help with fabric and thread shots.

BENEFITS

Ensures smooth, non-intersecting curves.
Offers a quicker and simpler alternative to the Detangle SOP.
Facilitates the creation of jitter-free, lightweight wire simulations.
Provides a method for temporarily simplifying the mesh and effortlessly reverting to the original resolution later.

HOW IT WORKS

In many cases, simply connect the node, and it will remove intersections and align curves while preserving the rest of the structure.

STEP BY STEP CUSTOMIZATION

1. SIMPLIFY

This setting has the most impact on the results.

You always want your points properly spaced before detangling and simulations. It means that points' pscales (represented by the blue spheres) should not intersect with neighbouring points in the same line.

Decrease the Simplify slider value to create lower-resolution versions of the same curve and create more space between points.

Turn Simplify off if your input curves already have low point resolution and enough space between points.

This value is a scale of the original number of segments.

Lower resolutions tend to give smoother results but tend to deviate more from the original shape.

2. SMOOTH

The second most used parameter is the smooth. It helps prevent the points from jittering too much as they are pushed away.

The bigger the value, the less jittery or noisy. The smooth value is multiplied by the iteration count.

3. ITERATIONS

In every iteration, we execute a detangle and a smooth operation.

So the more iterations the better the results, but the longer it takes to process.

4. SEPARATION

This value increases the collision radius around each curve.

0 - curves can touch.

1 - 1 extra unit around each curve. So curves are at least 2 units apart.

OUTPUTS

You'll get your detangled curves with their original resolution in the first output and simplified meshes in the second and third outputs.

You're served with 1 detangled and 1 not-detangled version of the simplified meshes, both useful for simulations.

The not-detangled version works best as a guide, since the detangled version jitters.

RESTORING RESOLUTION

With the Simplify option enabled, the simplified meshes will have a num_segments primitive attribute that a resample node can read and automatically give back its original resolution.