Reference: JMX Specification

JMX Model Overrides

The jmx root-level tag defines textures and materials that should be used when JMX is loaded. It will not be used if a frex tag is present and a FREX renderer (i.e. Canvas) is active.

"jmx": {
    "textures": { },
    "materials": { }
}

FREX Model Overrides

The frex root-level tag defines textures and materials that should be used when a FREX renderer (i.e. Canvas) is active. When present and active, it overrides the jmx tag.

"frex": {
    "textures": { },
    "materials": { }
}