Tutorial: How to bake shadow map for CAS items
NOTE: This tutorial is using a dress and an accessory coat as examples. The method applies to any CAS item that you want to bake its shadow, including necklaces, glasses, hats, rings, bracelets, shoes, clothes of course, etc.
The shadow map draws shadow on the underneath meshes (which could be either a sim body mesh or another CAS item) covered by your item. It adds depth and makes your item a little more realistic.
Instead of hand-painting it, this tutorial will show you how to use the blender baking to create a ‘correct’ shadow map with just a few steps.
Please read my tutorial of How to bake shadow for clothing to make sure you understand the basics of baking. This tutorial will not cover some similar steps again.
This method only works on the mesh where it’s able to tell the sim body from the clothes or accessory you’re making.
It does NOT work if your item is painted on the sim body mesh.
Pt. 1 Your mesh includes part of the sim body mesh, e.g. tops, pants, dresses.
1. Open your mesh with blender, go into Edit Mode and select the faces which belong to the sim body.
2. Press P key to separate the selected faces into a new mesh.
Step 1&2 isn’t a must. But it makes the baked result easier to edit later.
3. Select the sim body mesh you just separated.
4. Open the World panel with a globe icon.
5. Check Ambient Occlusion and Environment Lighting.
6. Increase Environment Lighting to 2.5. This will make the shadow darker and shading of the mesh itself (which we don’t need) lighter.
8. Add a new image in 1024x2048 in the UV/Image Editor and Bake in Ambient Occlusion Mode.
9. You should get something like this.
10. Save the baked image.
Pt. 2 Your mesh does NOT include the sim body mesh, e.g. necklaces, acc clothing.
11. Open your mesh in blender, expand the rig tree and select the sim body mesh where the shadow should appear. Note you need to highlight the Eye, the Arrow and the Camera icon to be able to select and bake an invisible sim body mesh.
12. Bake the selected sim body mesh the same way above. And save the baked image.
13. Open the baked image in Photoshop. Add a new layer under the baked image and fill in with pure white.
14. On the baked image layer, use the Eraser tool or Select tool to get rid of the shadow that is not from the item you’re making, e.g. between the fingers and legs.
15. Reduce the Opacity of the shadow layer. You might need to test in game for a few times to get a best result. Please never use a pure black shadow map.
16. In the Channel panel, add an alpha channel. Fill with pure white on the area where your shadow is. The range doesn’t need to be accurate.
17. Save your shadow map into a .dds file and import into your .package file with sims4studio. Test it in game.
