Use rendering settings to set the shadow, exposure and resolution for your published scene.
Rendering Settings.
Rendering settings define the exposure and resolution of shadows in your scene. To adjust your render setting click on the Render Settings button at the bottom of the left side menu.
Set shadow resolution and softness
Use the slider to set the resolution of shadows
Use the tabs to choose the type of shadow filter and, then set the level of softness. Choose “Real” for shadows that automatically mimic real-world shadow softness.