Source being in either a A- or T- pose no longer matters depending on what app your actually using to author animations and the Power tool for doing video games animations would be Motion Builder.
For that matter if you look hard enough you can spot what animation packages has been processed by MotionBuilder and if you look at Mixamo characters and animations takes the naming convention is 100% compatible with MotionBuilders naming convention.
With MB whats most important is not the base pose but matched sets of animations using the same naming convention so that a couple of hundred animation clips can be bulked process.
As a tip real old mo-cap (BVH) the base pose the rotation transforms are normally zeroed out so if you make all the joints 0 0 0 it would would all snap back to the default pose.
Three years later and still struggling with this. Is there a better process for this? Looks like UE-19768 was removed so I’m not sure if that’s a good or bad thing.
I’m finding it particularly difficult to get the IK bones to follow their respective joints when re-targeting animations with an A to T pose change on the source skeleton. They seem to always be a little off-center no matter how much I fiddle with the pose.
I figured it out. You can now use the “Edit Pose” button in the IK Retargeter to repose your Target IKRig from T pose to A pose. The closer you can line up the 2 rig poses the better result you get from the retargeter.
