Why has IK rotation constraint "envelope" stopped displaying? Uptil yesterday,for the same Ik rig,  IK rotation constraint &quot;envelopes&quot;(red line) were being displayed.
However today,with multidimensional constraints they no longer show.
Is there an option to toggle them ON?
In the N panel &gt; Display, you need to activate the Relationship Lines option. In 2.8 it's in the Viewport Overlays panel: