1. Computer Graphics Imaging Ying Zhu Georgia State University Lecture 26 Hair and fur

2. How to create hair? Create an object. In Object (F7) panel, click on “Particle Buttons” icon – Add a new particle system – Select “Hair” type Can add multiple hair systems for one object

3. Adjust amount of hair Under “particle system” tab, adjust “Amount”

4. Adjust amount of hair with “children” It’s often more efficient to keep a relatively low number in “Amount” and add “Children” – Go to “Children” tab – Select Children from “Faces” – The “Amount” in this tab is the number of child hairs displayed in the 3D view (set lower for efficient editing) – The “Render Amount” is the number of child hairs displayed in the rendered image (set higher for better visual quality)

5. Adjust amount of hair with “children” If you have 1000 parent particles you need 50 to 100 children – Thin hair (blond) need more child particles – Thick hair (black) need less child particles Press “Kink/Branch” to create curly or wavy hairs

6. Adjust the length of the hair Under “Physics” tab, adjust “Initial velocity” to change hair length – Adjust the “Normal” velocity to change hair length (e.g. 0.05 for fur) – Adjust “Random” to vary the hair length (e.g. 0.005) Adjust AccX/AccY/AccZ to change hair direction

7. Segments The “Segments” value in the “Particle System” tab – Each hair strand is simulated as a curve – The “Segments” value is the number of control points on the curve – The more segment you have, the more flexible you can manipulate the hair – Therefore add more segments for longer hair

8. Decide where to grow hair There are three ways to specify the areas on a 3D mesh where you want the hair to grow – Use vertex group – Use UV mapping (finer control but more complex) – Use Particle Edit tool in Particle Mode (easier to use)

9. Use vertex group to control hair growth Select the Emitter, enter Edit mode – Select the faces on the 3D model that you want hair/fur to grow from Under “Link and Materials” tab, create a new Vertex Group – Give it a meaningful name (e.g. skin) – Press “Assign” button to assign the selected faces to the vertex group

10. Use vertex group to control hair growth Go to the “Particle Buttons” panel – In “Extras” tab, under “Vertex group”, click on the button on the right side of the “Neg” button – Select the name of the vertex group you just created – In the “Attribute” drop down menu, choose “Density” – Now hair only grow from the faces that belong to that vertex group

11. Control hair growth with UV mapping This method works better than the vertex group method when you only have a small number of polygons on the 3D mesh model A little complicated though – Check out this tutorial http://en.wikibooks.org/wiki/Blender_3D:_Noob_ to_Pro/Furry http://en.wikibooks.org/wiki/Blender_3D:_Noob_ to_Pro/Furry

12. Control hair growth in Particle Mode This is probably the easiest and the most interactive method

13. Editing hair In “Particle System” tab, press “Set Editable” button In 3D view window, switch to “Particle Mode” Press N to bring out the “Particle Edit Properties” window – Add and Cut – Comb – Puff – Smooth – Adjust Length

14. Editing hair Once you start to edit hair in Particle Mode, you won’t be able to adjust parameters in “Particle Buttons” window – Unless you press “Free Edit” button, but then you’ll lose all the editing done in the Particle Mode. – Therefore set the “Amount” and the hair length to the desired value before pressing “Set Editable”

15. Hair and force field You can also use force fields to change hair style – Create an empty object and create a force field (e.g. sphere, vortex, wind, etc.) – Move the force field closer to the hair

16. Hair and Curve Guide Add a Bezier curve In Object (F7) panel, click on “Physics Buttons” icon Under “Fields”, select “Curve Guide” type Move the curve closer to the hair Enter Edit mode to manipulate the curve, which in turn manipulates the hair

17. Adjust the shape and thickness of hair strand In “Particle buttons” panel, under “Visualization” tab – Press “Strand render” Go to Shading (F5) and “Material buttons” panel – In “Links and Pipeline” tab, under “Render Pipeline”, press “Stands” button – For a detailed explanation see http://wiki.blender.org/index.php/Doc:Manual/M aterials/Properties/Strands http://wiki.blender.org/index.php/Doc:Manual/M aterials/Properties/Strands

18. Adjust the shape and thickness of hair strand For black hair – Start 0.86 – End 0.854 – Shape -0.686 For blond hair – Use Blender Units – Start 0.003 – End 0.002 – Minimum 2 – Shape 0 (or -0.5)

19. Creating materials for hair Create a material for the hair and set the base color The color of the hair is governed by the specular highlights (Spec), so you may want to set the Spec color too Press “Ztransp” to make hair semi-transparent

20. Add more realism Make the hair strand fade towards the tip – Create a texture for the hair material – Go to “Texure buttons” panel, select “Blend” texture type Choose either Lin(ear) or Quad blend – Go back to the “Material buttons” panel – Set “Map Input” to Strand – Set “Map to” to Alpha – “DVar” to 0

21. Blond hair For material settings of Blond hair, check out http://wiki.blender.org/uploads/4/45/Blender 3D_BlondHairStill-2.48a.blend http://wiki.blender.org/uploads/4/45/Blender 3D_BlondHairStill-2.48a.blend