What will prevent a particle system from supporting Procedural Mode?

The choice that prevents a particle system from supporting Procedural Mode is linked to the Simulation Space property being set to World. In Unity, the Procedural Mode allows for the manipulation of particle movements and behaviors through scripting rather than relying solely on physics simulations. When the Simulation Space is set to World, particles are effectively fixed in world space and do not take into account the transformations of the parent GameObject, which is fundamental for the dynamic manipulation available in Procedural Mode.

In Procedural Mode, the particle system needs to be able to respond to transformations and interactions in a local space, allowing for a higher degree of control. This means that, ideally, the Simulation Space should be set to Local to enable the intended dynamic behaviors. By locking particles to world space, it restricts their ability to react dynamically within the procedural framework, making it impossible to achieve the flexibility that Procedural Mode aims to provide.

Additionally, while factors like using a legacy particle emitter or increasing the particle count could pose challenges or limit performance, they do not inherently restrict the core functionality of Procedural Mode in the same manner as the Simulation Space setting does.