[1.19.3] How would you go about changing the alpha of an armour to make it look translucent?

[DrNickenstein]

I tried just changing the texture's alpha but as expected it did not work at all so I was wondering at this point how something like that would work.

[Luis_ST]

You have to create you own HumanoidArmorLayer which renders your Armor with a alpha value less than 1.0.

You can extends the vanilla HumanoidArmorLayer then use an AT to make the method renderModel method public.
Override the method and call the method renderToBuffer with a custom alpha value (the alpha value is the last parameter).

Add the custom LayerRenderer via EntityRenderersEvent.AddLayers you may need an AT to remove the vanilla HumanoidArmorLayer to avoid conflicts.