Hi,
I’m exporting a character into Unreal from Maya which has some corrective blend shapes using fbx.
In Unreal, morph targets blend both vertex positions and poly normals. Due to the fact this is a corrective shape and not a FACS face shape I need to create a custom set of normals.
To explain better (the mesh has been changed to protect the innocent)…
On the left is my corrective shape. In the middle is the character with no corrective shape applied. On the right, translation-based down-axis scale with corrective shape to scale the remaining two axis. Basically I’m testing runtime character scaling in a game environment where joint scaling is not supported.
Now, if you imagine applying the normals from the corrective shape onto the base mesh… that’s what I get in Unreal and obviously it doesn’t look right.
So, what I need to do is create a custom set of normals that blend in as the blend shape weight for that shape increases to 1. So, when exported through fbx my custom normals for that specific shape go through as well.
…and it’s here I’m kinda stuck. I need to (a) generate a second set of normals and (b) blend between these two sets as the blend shape weights change.
(edit)
Just to clarify, I’m talking about poly face normals and not normals/wrinkle maps.
Thank you in advance for your help,
Matt.