Reverse thickness for artists

Assets/ScriptableRenderPipeline/HDRenderPipeline/Material/Lit/LitDataInternal.hlsl

     surfaceData.thickness *= SAMPLE_UVMAPPING_TEXTURE2D(_ThicknessMap, sampler_ThicknessMap, layerTexCoord.base).r;
 #endif
 
+    surfaceData.thickness = 1 - surfaceData.thickness; // Reverse for artists
+
     surfaceData.specularColor = _SpecularColor.rgb;
 #ifdef _SPECULARCOLORMAP
     surfaceData.specularColor *= SAMPLE_UVMAPPING_TEXTURE2D(_SpecularColorMap, sampler_SpecularColorMap, layerTexCoord.base).rgb;