1. Introduction to 3D Art and Animation
Lesson G (week 7): Intro to Maya UV Unwrapping for Precision Texturing

2. UV UNWRAPPING 1: Preparation
STAGE 1: PREPARATION
a) Start in Object Mode.
b) Checker Map: In the Hypershade create a new Blinn Material. In the Color Channel click the checkered square to add a File node. Click the Manila envelope icon and add the provided CheckerLetter texture (see website). In the place2DTexture node increase tiling (10x10 is often a good starting place). MiddleMouseDrag your Blinn from the Materials library to your model in the Viewport. Hit [6] to view the texture in Viewport.
c) Reference Mapping: Select the model and apply UV > Automatic Mapping. Hit UV > UV Editor to view the 2D UVW space. In the upper-right corner, switch to your CheckerLetter map. RightClickHold to choose UVs. Select around all UVs, Scale [R] down and Move [W] to a light checker square outside of the 0-to-1 UV space. This is the Reference Map.
The entire model should have the lighter checker color. You are ready to start unwrapping!

3. UV UNWRAPPING 2: Unwrap Each Part
STAGE 2: UNWRAPPING (page 1/2)
a) SELECT MAP-ABLE AREA (for cylindrical, planar, or spherical map): In Face mode, select all the polygons of your character’s arm.
b) APPLY UV > CYLINDRICAL MAP. Note a gizmo appears: a half-cylinder. The center of the empty side is the seam. Mapping gizmos have their own transform controls; if you hit w/e/r the map will jut get baked and need to be re-applied. Instead, find and LeftClick the red T icon in one corner of the gizmo. Click on the blue rotation circle to activate the gimbal ball, and rotate on the axies to make the cylindrical map surround the arm, like a piece of paper curled around the cylinder of the arm.
The Cylindrical map “flattens” the cylinder of the arm into a rectangle “Shell” in the UV > UV Editor. We want the seam to go where it is least visible, which on an arm is the bottom. Rotate the cylindrical map gizmo so that the seam faces down.
c) MOVE UVs: In the UV > UV Editor, select Uvs, leftDoubleClick and one UV to select the entire Shell, and move them out of 0-to-1 square.

4. UV UNWRAPPING 2: Unwrap Each Part
STAGE 2: UNWRAPPING (page 2/2)
Repeat with new polygon areas of the body until all parts are unwrapped. Confirm in the UV Editor that all parts of your initial Reference Map are gone!
NOTE: Most body parts use Cylindrical maps (arm, leg, shoulder, undercarriage, top-of-foot). Some are Planar maps (bottom-of-foot, top and bottom of hands). The head and torso both use Centered Cylindrical maps; we need to Move (red T) the mapping gizmo in the front view so that the center is past the center of the half-model (to the center of the entire head or torso, if the model was mirrored), for a more even distribution of checker-distortion on the surface.
The purpose of the checkers on the texture is to see which parts are mapped evenly (will display as squares) and which are distorted (will display as squashed or stretched rectangles). Ideally, all parts so the body will show squares except for the joints, which we intentionally squash by stretching the UVs there, to allow more painted detail for deformation. The purpose of the letters is to show if any UV shell is flipped/backwards.

5. UV UNWRAPPING 3: Clean-Up
STAGE 3: CLEAN UP (1/5)
SUMMARY: Once all parts of the model have been unwrapped into UV Shells, we organize them neatly in the UV Editor 0-to-1 square so they can be exported and painted, according to the following 4 critical considerations (ordered by importance):
a) Reduce Seams: Use the Edge mode Cut/Sew > Cut to separate areas that should not be a single Shell, like Cloth from flesh. Use Cut/Sew > Move and Sew weld together related parts like cloth on lower & upper arms. Use both to move stray polygon from one side of a shell to another, to get cleaner edges/seams.
b) Group by Color: Texture painting is easier if grouped by cloth, flesh, etc. LefDoubleClick a single UV to select the entire Shell and Move [W] to arrange Shells in the 0-to-1 map.
c) Prioritize: The most noticeable or detailed parts get more space. A human face usually needs 1/5 the total 0-to-1 square, even though it is 1/20 the total surface area of a human. Feet bottoms can usually get less space, as they are less visible.
d) Optimize in the 0-to-1 square: Scale up parts & re-arrange for less wasted space (but leave at least 5-10 pixels gutter for Normal Mapping, and make sure no Shell overlaps the outer edge). Mirrored parts can be stacked for less texturing work (symmetrical faces, right & left arms, etc), but note that some advanced techniques, Like Normal Mapping and LightMapping, need all Shells to have their own space.

6. UV UNWRAPPING 3: Clean-Up
STAGE 3: CLEAN UP (2/5)
a) Reduce Seams: Use the Edge mode Cut/Sew > Split to separate areas that should not be a single Shell, like Cloth from flesh. Use Cut/Sew > Move and Sew to weld together related parts like cloth on lower & upper arms. Use both to move stray polygon from one side of a shell to another, to get cleaner edges/seams.
Once the seams on a UV shell are clean, you can try selecting around the UVs and applying Tools > Smooth > Unfold (often only needs to be dialed part way) to let Maya even-out the distribution of UVs. This is particularly nice for the hands, to let the sides of the fingers open up a bit, but can be helpful in all parts of the model if used in moderation. Go back in afterwards and make sure no UVs overlap.

7. UV UNWRAPPING 3: Clean-Up
STAGE 3: CLEAN UP (3/5)
b) Group by Color: Texture painting is easier if grouped by cloth, flesh, etc. LefDoubleClick a single UV to select the entire Shell and Move [W] to arrange Shells in the 0-to-1 map.

8. UV UNWRAPPING 3: Clean-Up
STAGE 3: CLEAN UP (4/5)
c) Prioritize: The most noticeable or detailed parts get more space. A human face usually needs 1/5 the total 0-to-1 square, even though it is 1/20 the total surface area of a human. Feet bottoms can usually get less space, as they are less visible.

9. UV UNWRAPPING 3: Clean-Up
STAGE 3: CLEAN UP (5/5)
d) Optimize in the 0-to-1 square: Scale up parts & re-arrange for less wasted space (but leave at least 5-10 pixels gutter for Normal Mapping, and make sure no Shell overlaps the outer edge). Mirrored parts can be stacked for less texturing work (symmetrical faces, right & left arms, etc), but note that some advanced techniques, Like Normal Mapping and LightMapping, need all Shells to have their own space.

10. UV UNWRAPPING 4: Export UVs
STAGE 4: EXPORT UVW COORDINATES
In UV > UV Editor, Object Mode, Choose Image > UV Snapshot and choose these settings:
Hit [Browse] and choose location and name.
Set Image Format from Maya IFF to JPEG
Set size (512x512, 1024x1024, usually 2048x2048). Hit [Apply and Close], and open in Photoshop.

11. UV UNWRAPPING 5: Paint PSD
STAGE 5: PAINT IN PHOTOSHOP
Create a Photoshop file the same size as your UVW template.
Add at least four layers:
TOP LAYER: UVs: Copy and paste the UVW template to the top layer: set to Multiply, 30-50% opacity, and locked.
SECOND LAYER: Palette: Find color references and color pick to make a Palette (at least two shades per color).
BOTTOM LAYER: BaseColors: Create a layer for Colors on the bottom. Fill with a medium-dark color from your palette (NOT white). Use the marquee tool to block in all the major colors. PRO TIP: Once you have major colors applied, hide the UV layer, save as a JPEG and apply to the model to view the colors in scene and make adjustments before adding details.
MIDDLE LAYERS: Create layers in between for painting details, dirt, and Ambient Occlusion (shadows cast by the model onto itself). Consider painting with a solid brush, 40% opacity, and use your palette to quickly pick colors.
Paint Color, Specular, Bump, and Opacity maps as needed. Save out as separate PNG files.

12. UV UNWRAPPING 6: Maya Material
STEP 6: CREATE MAYA MATERIAL
In Maya, open the Hypershade, create a Blinn Shader, in the Edit Parameters panel find color, click the checker square, add a File node, click the Manila envelope and add your color PNG.
MiddleMouse drag the material from your top library onto your mesh in the Viewport, hit [6] to view.

13. Maya Texturing: Saving & Moving Files
IMPORTANT: Please note that texture images are not stored in Maya. The Hypershade only stores POINTERS to the files on the hard drive. Therefore, it is critical that you bring the images you use in your scenes with you when you come to class.
The most effective way to manage texture image files in Maya is to create a folder on your computer in which to keep your Maya file with a sub-folder for your texture images. You must then go to the Maya File menu, hit Set Project, and navigate to this main Project Folder. Maya will create a Workplace file that will help it to always know where the texture files are located, making it easy to reconnect those textures when at a new computer.
[YourName] (your project folder)
|____> YourName_hw3_room.mb (your Maya file)
|____> [images] (your texture folder)
|_____> LinolumFloor.png
|_____> WoodTable.png
|_____> PlasterWall.png
To post this folder structure to Piazza, please put it all in a.ZIP, so that only your screenshots and/or Playblast each week is outside of the zip for easy viewing.

14. Delete History and Saving
As with all Maya modeling, please DELETE YOUR HISTORY every hour or two, and certainly before you save and close for the day to upload your work.
To guard against crashes and loss of work, please Save and Save As a new file every hour (so you can never lose more than an hour’s work): YourName_Character01.mb, YourName_Character02.mb, etc.
Save your work to an online repository every day (Dropbox.com, Google drive) so you have a backup in case your computer fails.