Adding an outline effect to a character in Blender using the Solidify modifier can give a nice stylized appearance, but as you've noted, it can sometimes lead to undesired results, especially around features like the eyes and mouth, or when applied to hair. Here’s how you can refine your approach:
### Adding an Outline While Avoiding Certain Areas
1. **Add a Solidify Modifier**:
- Select your character model.
- Go to the Modifier Properties and add a **Solidify** modifier.
- Adjust the thickness to create the desired outline look.
2. **Use Vertex Groups**:
- To avoid an outline around the eyes and mouth, you can assign those vertices to a vertex group.
- Switch to **Edit Mode**, select the vertices around the eyes and mouth, and create a vertex group (in the Object Data Properties under Vertex Groups).
- In the Solidify modifier, use the **Vertex Group** option to restrict the outline to the rest of the body.
3. **Use Material Settings**:
- Instead of using modifiers, you could create a separate material for those features (eyes, mouth) and set them as non-shown in the viewport. This method involves creating a new material slot for those areas and adjusting their settings to match the character style without the outline.
4. **Adjusting the Solidify Modifier**:
- If you want more control over the outline visibility, consider tweaking the settings such as the *Offset* and *Clamp* options to refine the appearance further.
### Alternative Methods for Hair Outlines
For the hair, a Solidify modifier might not yield the best results due to its geometry. Here are better alternatives:
1. **Freestyle Render**:
- Enable Freestyle in your render settings. Freestyle allows for more control over line styles, making it ideal for creating outlines.
- In Freestyle settings, you can create or customize line styles for different parts of your model, including hair, enabling you to create cleaner lines at the ends.
2. **Add a Shrinkwrap Modifier**:
- Create a duplicate of the hair mesh, then apply a **Solidify** modifier to the duplicate and give it a thicker profile.
- Use a **Shrinkwrap modifier** to make it conform closely to the hair shape. This way, the thickness may help in keeping a consistent outline while providing a cleaner edge.
3. **Curves for Hair**:
- Instead of using polygonal hair, consider modeling the hair with curves. This way, you can use a curve modifier that can produce cleaner outlines.
- Convert curves to meshes and use the Solidify modifier or Freestyle for outlines.
4. **Use Textures**:
- If the hair areas are problematic when it comes to geometry, consider creating a texture outline effect that can be overlaid on your model. You can use UV unwrapping to paint a texture that represents the outlines of your hair parts.
By following these methods, you’ll be able to achieve a stylized appearance without the undesired effects around critical features and hair. Experiment with the different approaches to see which best fits your character's style!