For context: I downloaded a lowpoly character from sketchfab and created a control rig for it with IK legs & arms and subsequently animated an idle animation for it. I didn’t want to spend more time animating so I figured I’d retarget animations from UE’s Manny skeletal to my own custom character mesh.
For this I created an IK Rig for UE’s mannequin and my own character mesh, with both of their chain mappings being: head, spine, arm_l, arm_r, leg_l, leg_r. I then export the animations I want using an IK Retargeter.
I end up with my own animation LPC_Idle and the now retargetted animations RTG_MM_Walk_Fwd, RTG_MM_Run_Fwd, etc.
Moving onto gameplay, I set up a Blend Space for use with my animation blueprint. I set speed=0 to LPC_Idle, (the RTG_MM_Idle animation was janky so I used my own instead), and then speed=240 to RTG_MM_Walk_Fwd and speed=480 to RTG_MM_Run_Fwd.
Main Problem: The transition from idle to walk is an instant snap. My ‘Smoothing Time’ is set to 0.5s in the Blend Space. I even set it to 3.0s just to make sure, and it still snaps. Walk → Run has no snapping issues. I then remove LPC_Idle and instead use RTG_MM_Idle (the retargetted idle anim), and that has no problems. Which concludes the cause of the problem is using my own animations made with my control rig in conjunction with the retargetted animations. I don’t really have any idea as to solve it though.