Blender 2.8 to ThreeJS GLTF Specular

Question

I have a model in Blender 2.8 ( and 2.79 ) with a grass texture on a plane. It's a field. No matter what I set the metalness and roughness to, when viewing it in ThreeJS there's always a whitish sheen on the field when looking at it from certain angles according to the sun position.

I think setting the specular color to black would remove that sheen, but I'm guessing this isn't currently possible to do because ThreeJS StandardMaterial doesn't control specular color..

So, basically, is there anyway to control the specular color on a ThreeJS StandardMaterial?

Answer 1

Use an environment map? Or change the color of your directional light?