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PhysX Glue Test: Rigid/Simplified Binding Rollouts

Path: Particle View > Click or add a PhysX Glue test.

When using the PhysX Glue test with Type set to Rigid or Simplified, you can specify the placement of binding anchors as well as the breakability of bindings with the corresponding rollout: Rigid Binding or Simplified Binding. The settings are mostly the same for both types, but the availability of separate rollouts for the two means you can set different anchor placements and switch between them depending on the binding type.

Interface

Binding Anchor Placement - Choose how the software determines placement of the binding anchors:

  • Centers Average - Places the main anchor of a binding at the center point of particles' pivots, and orients the main anchor axis along the vector between particles.

  • Closest Points Average - Determines the closest points of each pair of particles' collision shapes, and then places the main anchor halfway between these. The main anchor axis is perpendicular to the shape surfaces at the closest points. In this case, when the main anchor axis is not oriented along the vector between particles, the binding becomes more brittle along the contact surfaces and less gluey. So if you have a brick wall to destroy, for example, use this setting.

  • Mass Proportional - Places the main anchor point of a binding in reverse cubic ratio to the particle masses. This is done to approximate the following situation: Imagine spherical particles with different sizes and the same density. Suppose you create bindings for particles that touch each other. In such a situation, it's better to create the main anchor point (as a possible breaking point) at the point of the contact. The contact point in this case can be calculated as a weighted average of particle positions, where the weight coefficients are cubic root of particle masses. Use the Mass Proportional option when you have different-sized, somewhat spherical particles to bind.

Solver Factor - Available only for rigid bindings. Use this setting to adjust the rigidity or flexibility of rigid bindings. The value range is 0 to 2, the default is 1. Increasing this value makes bindings more rigid (less flexible) with a potential side effect of unstable solutions. For best results, keep the value well under 2, or you'll risk an unstable solution. Reasonable values are around 1.1, or 1.2, or 1.4.