Eyes turn red when posing character

I created a character, used rigify and now, when posing, the eyes turn red. Their texture kinda moves, however they don't when I just move them in Object mode.

The character does an animation, where he sits down (just basic for testing). I will provide the .blend file, knowing that it isn't really cleaned up and that there are some backups in it.

Frame 0 Frame 10 Frame 30 (moved the light a bit so you can see it better)

• I took a look at the file, but I can't see any red eyes. The eyes don't move because you have to manually parent them to the bones. But you want to correct their position first because they are a little off and that makes the eyeball stick out of the head when your character wanders his gaze. – Blunder Mar 27 at 13:43
• Can you add a screenshot of the red eyes? Please remember that BSE is a question and answer page. Your question can help future readers, but only if they can quickly decide if this question is relevant to their problem. Downloading and reviewing a 150 MB file just to decide this is not an option. Also, all relevant information should be included in the question. Cheers. – Blunder Mar 27 at 13:45
• I will do so! The red eyes for me occured from frame 10 on. – Marvlogs Mar 27 at 13:56
• Ah ok, I had not played the animation because the rig animation and the cloth simulation froze my blender – Blunder Mar 27 at 14:25
• Have you found anything so far? I really dont know where the mistake could be as I never found someone with the same problem online... – Marvlogs Mar 27 at 17:59

Procedural eyes + armature = bloody-red mess
The eyes are built procedurally. The shader makes heavy use of the object coordinates and is a bit prone to changes in the object's origin and scale.

You have parented the eyes to the armature. This applies an Armature modifier which deforms the mesh. The eyeballs don't get deformed but moved down when you play the sit-down animation. The origin (orange dot) stays where it is during the animation, just the mesh is moved. This finally messes up the procedural shader of the eyes. The iris disappears and the bloody back of the eye with all the veins begins to cover the entire eyeball.

How to fix Rigify eyes

In a nutshell: remove the Armature modifier from the eyeball objects and parent them to the bones MCH-eye.R and MCH-eye.L of the generated rig (not the metarig).

Make sure the origin of the eyeball is at the center and the bones of the metarig are at the center of the eyeballs else the eyes will stick out of the head when they are rotated. You can use the 3D Curser (Shift+S pie menu) to align them.

If the bones are a bit off re-generate the rig to have all relevant bones in the right place. Remember to make a backup copy of the mesh with the weight paint if you did already some weight paint. Then align the bones with the eyeballs, and re-generate the rig from the metarig.

Parent the eyeballs to the bones MCH-eye.R and MCH-eye.L of the rig. The MCH- bones are on layer 31. In Object mode, select the first eyeball, then select the rig additionally (eyeball is selected red, rig is selected in orange). Switch to Pose mode, select the bone, and parent the eyeball to the bone (Ctrl+P, Parent to ... Bone).

Once you have (re-)generated the rig and parented the armature to the mesh you need to weight paint the eyelids (or transfer the weights from a backup copy if you already did this step). See Why are my model's eyes deforming so badly? for details.

Hope this helps ...

I can see you ;-)

• Great! Thanks a lot! – Marvlogs Mar 27 at 19:54