Each tyFlow is able to export “I_PARTICLEOBJ” and “I_VRAYGEOMETRY” interfaces to 3ds Max. In some cases, enabling these can cause issues between tyFlow and other plugins. In other cases, you might want to limit which particles are sent back to a particle query request. These settings allow you to override these interface exports.
Enable Particle Interface: controls whether the I_PARTICLEOBJ interface will be returned when the tyFlow object is queried for its default interface. Returning this interface allows third-party plugins to query a tyFlow for its particles.
Export groups: controls which particle export groups will be returned when a tyFlow is queried for its particles. Use these groups to limit which particles will be sent to third-party plugins querying a tyFlow for its I_PARTICLEOBJ interface.
For example, if you have a PhoenixFD grid which uses a tyFlow as a PHXSource input object, you might only want to use certain particles in the flow to affect the PhoenixFD simulation. By limiting the particles exported through the I_PARTICLEOBJ interface (by setting the desired export groups), you can limit which particles will be returned to the PhoenixFD object.
When a 3rd party plugin asks tyFlow for the scale of a particle, these options let you choose what property of the particle is returned.
Return scale: the explicit scale value of the particle will be returned.
Return shape diameter: the diameter of the particle’s shape mesh will be returned.
Disabling the VRay interface will prevent tyFlow from being able to render VRay instances.