Why?
Mainly because they take too long to load and display changes. I have a pretty powerful pc and still it is not like I see with other 3d software where you can rotate hdris live, and get a preview instantly. Blender, Cinema, w/e.
I am having some frustrating issues with HDRI skies in Rhino 6 with Vray up to date. I can use the same file in Rhino 5 and my hdri sky will appear in the render, but in Rhino 6 the sky is not applied. I have attempted it in dome light, and also as an environment bitmap. I have attached my settings and an example of how the render is coming out.
I think you need to check all settings in V-ray for Rhino 6 . Then make sure assign the Hdri map in environment bitmap. so if you are using the Hdri map in v-ray dome-light make sure inadvisable option is off that means not need to use the Hdri in environment bitmap and v-ray sun light too that is depend on the type of hdri map .
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