Hi, Emoticons prevent Skin Layers 3D from working in 1.12.2.

The mod works fine in first person but in third person the mod just don't work Emoticons work fine.

Such mods can not work with Emoticons, because Emoticons uses its own models. This is impossible to fix. Also, there is an emoticons model with 3D layer (for example default_3D morph) so you don't need that other mod.

How can I use the default 3D layer of emoticon?

By using the default_3d morph or slim_3d

Where can I do that? Is that in the Metamorph mod?

You can do that in Metamorph mod by morphing into it, or you can change the default model in Emoticons settings (Ctrl+0)

Okay thanks you!