1.6.21.4

Fixes

• RenderMan : Added IECORERENDERMAN_LEGACY_TEXTURECOORDINATE_BEHAVIOUR environment variable, as a partial opt-out from the bugfix introduced in 1.6.21.0. Setting the variable to a value of 1 causes USD texCoord3f primitive variables to be exported to RenderMan as point rather than float[3], as they were prior to 1.6.21.0. This is not correct, but allows folks who have been authoring __Pref as texCoord3f to temporarily continue to work as before.