USE A BAKE
A bake (multiplier in Sims 3) uses your UV map information to approximate real-world shadows onto your mesh, giving your object depth and realism. In Sims 3, the multiplier was applied globally to the mesh much like the Normal Map and RGB Specular are in Sims 4. In Sims 4, you will need to incorporate the information into your Texture files. There are different ways to do this, and using a Bake from Blender is one of those ways.
What this tutorial will show you:
How to open your bake in Photoshop CC.
How to use a bake image as a texture base in Photoshop CC.
What you will need:
Photoshop CC or other version of Photoshop
NVIDIA Texture Tools Plugin for Photoshop
A bake image created from your mesh (See my Create A Bake In Blender Tutorial for more information)
Sims4Studio or TSRW to clone a Sims 4 game object to import your mesh and/or apply your texture
**This tutorial will not cover how to clone an object using Sims4Studio or TSRW. Please visit the appropriate tool's website for more information on how to do this.
**This tutorial will not cover how to use other photo imaging software to create textures, although many of the principles are probably similar in other programs.
From the menu at the top of the screen, choose “File – Open” and navigate to your saved bake image and open it in Photoshop.
(A) In the layers menu at the bottom right of the screen, add a new layer to
your project by clicking on the small icon that looks like a sheet of paper
with the corner turned up.
(B) Your project will now have a new layer. This is the layer you will add
your texture to.
You will copy paste, fill your pattern, or add your colors into this layer. For this project, I am going to use a seamless wood pattern exported from Sims 3 and make it a fill pattern in Photoshop, filling the entire layer.
(I will cover how to export seamless patterns from Sims 3 and make a fill pattern in Photoshop in future tutorials).
(A) Once you have your desired texture loaded into your new layer, look
in the Layers menu on the bottom right of the screen and change the
blending method from “Normal” to “Overlay.”
(B) Your bake will now show through the layer, adding shadows
to the texture.
Choose “File – Save As,” name your texture, and save it as D3D/DDS, making sure to choose DXT1 - no alpha. You can also save it as .png if you don't have the Nvidia plugin.
Import your texture into your Sims 4 object creation program, and see how it looks on your mesh!