Tutorial is written with Blender 2.93, appropriate for 2.8-3.x
Google any features by name + version if they are not located in the same area as a screenshot.
Requires the Bodies + Faces and scalps files from Nysha's body templates.

My start-to-finish hair tutorial will soon follow and it greatly streamlines the process to prepare a Blender file with the appropriate windows and sim body references, which you can save and open every time you have a hair (or other CASPart) to edit. Including all the steps to make it accessible for any experience level made it quite lengthy, so I've separated it considering it isn't strictly related to hair. I've also included gifs demonstrating the most useful Blender tools at the end.
I don’t own the exported meshes, so I cannot provide a premade .blend file, but I believe it is valuable for beginners to learn their way around putting this together anyway.

You can consider this Part Zero of Hair Creation Start to Finish (2023).

New to Blender, or returning to 2.8+ from earlier versions?

This is my favourite camera control/hotkey reference video that will help familiarise you with the controls and what to do if you don’t have a mousewheel.

Preparing Blender for CAS Creation

In a new file, click on each item (the Camera, Cube, and Light) in the scene collection and press Delete.

Right click on the border of the viewport and the bottom panel, select Join Areas, and click on the bottom panel. This will close it and maximise the viewport.

Right click the top border of the viewport and select Vertical Split.

Click somewhere in the middle of the viewport. You now have two identical windows. Navigate to the Editor Type button at the top left and select UV Editor. You can shrink this section by grabbing the border.

Under Scene Collection, rename ‘Collection’ by double-clicking it (I name it “Base”) then select it. Import the body, face, and scalp .obj (from the downloads at the top of the post) of the life stage you are creating the CAS item for.

Select all three, right click in the viewport, Join.

Set the shading to Material Preview.

Navigate to Material Properties. Remove all but one material with the minus button. Select the material.
Surface > Base Colour, click the white box and apply any fleshtone. This will help distinguish the body mesh from your creation.

Collapse the collection with the arrow and select Scene Collection. The Base collection can be hidden at any time.

Save. Name the .blend file something identifiable, like afTemplate if you imported the adult female mesh. Whenever you import projects into this file, Save As to keep the clean template.
These bodies are only for reference when fitting meshes and should not be exported with your final project. Clothes that include parts of the body still need a valid EA mesh, as explained in tutorials for that kind of CASPart.

Following along the hair tutorial and/or plan to make morphs?
Right-click the Scene Collection, create New Collection, and import the mesh pieces per morph.

• Body_fat and Face_fat for Fat
• Body_fit for Fit
• Body_thin for Thin
• Body_special for Pregnant.

Children only have a fat morph, Toddlers do not have any.
Hide the inactive collections.


MOST VALUABLE TOOLSET
I can’t teach you to use Blender here, but I will share the tools it is best for you to know about now rather than later. Memorise the locations of these and keep them in your arsenal going forward. Most are available in Edit Mode.

Select Linked. Hover over a mesh piece and press L to select all connected parts. Good meshes will be made of many pieces of geometry that aren’t ‘fused’ together in any way, allowing you to select entire sections with ease. Great for removing unwanted parts. (Shift + L to deselect)


Vertex-Edge-Face Select. 1-2-3 on your keyboard (not numpad) or click the options to toggle between these three icons for highlighting by individual vertex, edge, or entire faces.



Proportional Editing. Switch this on when using the Scale (S) or Grab (G) action to affect how much of the surrounding geometry is ‘pulled’ along with your selection.

When first turned on, enable Scale or Grab and use the scrollwheel to scroll up (before moving your mouse at all) until you see a shrinking circle. This is the strength of the effect, seen as Proportional Size at the top of the viewport.

0.1 is an appropriate starting value for moving small parts. You can scroll down before finalising an edit to increase the effect. Click to confirm.

UV Sync. Enable for selections in Edit Mode to correspond to the ones in the UV editor, and vice versa.



Face Orientation. View the direction of a mesh’s normals. Blue is the visible side, red is the ‘backface’. Seeing meshes with purple and magenta faces? That means duplicates with flipped normals exist in the exact same position (the mesh has undersides). Remains on in other modes.


CONTINUE ON TO PART ONE: Mesh and Texture Starting Point
Credits to Blender, EA for the body meshes and Nysha for exporting them.
Credits to RaonJena for the hair mesh pictured in the examples.