adding a texture map to VRayEnvironmentFog autmomatically switches the sampler over to raymarching mode.
However, if you need an emission color > 1.0 for glowing fog with exposure, it appears that a VRayColor map is the only way to do it. In this case, using the faster exponential sampler is still valid, as the fog isn't really texture mapped. Either a VRayColor map shouldn't trigger the raymarcher, VRayEnvironmentFog should have an RGB level spinner for emission, or picking exponential/raymarching should be user-controlled.
However, if you need an emission color > 1.0 for glowing fog with exposure, it appears that a VRayColor map is the only way to do it. In this case, using the faster exponential sampler is still valid, as the fog isn't really texture mapped. Either a VRayColor map shouldn't trigger the raymarcher, VRayEnvironmentFog should have an RGB level spinner for emission, or picking exponential/raymarching should be user-controlled.
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