Many dforce hair can only be seen when rendering into a picture, but not when previewing and rendering, such as "big boss hair and beard" and his chest hair, which I can't display in the preview. How can I solve this problem? thank you!Please forgive my poor English
Select the hair in the scene tab.
Go to Parameters > All
Look for the setting "Viewport Line Tessellation sides" and click the + until the hair becomes visible.