Advanced 3D Art and Animation

1. Advanced 3D Art and Animation Modeling 3: Unwrapping and Unfolding Maya-to-Mudbox-to-Maya High Resolution Modeling and Texturing Pipeline

2. UV Unwrapping: Tools 1/2 To texture a character we need to establish the 2D mapping (UVW space) for where painted textures will appear on the 3D geometry (XYZ space). In this space objects are split into 2D Shells. Whether we are painting in a 2D program like Photoshop or directly on the model as in Mudbox, the 2D version of the model needs to be prepared. In Maya, UV Mapping and Unwrapping are controlled in the Modeling Module UV menu and in the UV > UV Editor. UV Menu key tools: • Automatic mapping creates quick flat maps from the six sides of a box around the selected model. It is ideal for rectilinear forms like architecture, or visualizing a messy organic map before replacing each part with a Cylinder or Planar map. • Cylindrical mapping: Apply to selected faces in generally Cylindrical shape. Click red T to rotate and move the UV gizmo to best surround selection, so Checker map is evenly distributed. Hit [W] to commit the map and further adjust in the UV Editor. • Planar mapping: Select faces in generally flat shape. Click the Option Box to choose mapping direction, apply, and click red T to rotate UV gizmo to match the angle of the selected mesh.

3. UV Unwrapping: Tools 2/2 UV menu > UV Editor key concepts: • The upper right square in the center is the staging area called the Zero-to-One space. All UVs will eventually need to be packed there to export for painting (in Object mode, Image > UV Snapshot). • Display Image button to hide/ unhide texture. • Only use UV or Face component modes to select and Transform Shells. • Use Edges to Cut/Sew > Split and Cut/Sew Move and Sew Shells. • Doubclick a UV to select the full shell. • Tools > Hide or Show UV Toolkit. At top are easy selection modes, and in the middle are 90 degree rotation tools. • Modify > Flip to reverse selected Uvs. • Tools > Smooth and clickdrag[Unfold] to open up the Uvs (“Unfold Mapping”).

4. UV Unwrapping: Full Pipeline 1/2 Unwrapping and texturing a character includes 6 stages: STAGE 1: PREPARATION: Apply a checker map material with dark and light colors and tiling 20x20. Hit [6] to view on the model. Create a Reference Mapping: Open the UV > UV Editor, select the model, apply UV > Automatic, RightClickHold for Uvs mode, select around all UVs, Shrink [r] and Move [w] down to just outside the lower-right corner of the zero-to-one staging square. This has two benefits: since the entire model is inside one square in the Checker map, it is all one color until we Unwrap individual areas, so we can easily see what still needs to be mapped. When we Unwrap each area, the Checker map lets us see if the new mapping is evenly distributed, so that the textures we paint will not be stretched. STAGE 2: UNWRAPPING: In Face mode,select a map-able area: faces which roughly make a cylinder or flat shape. Apply the Cylindrical or Planar map, hit the redT to transform until the Checker map displays more evenly across the selected faces. Hit [w] to commit the mapping and in the UV Editor select UV mode, select around the new Shell and move it out of the Zero-to-One staging square. Repeat of all parts of the mesh until the reference map in the lower right corner is gone (fully over-written).

5. UV Unwrapping: Full Pipeline 2/2 STAGE 3: Clean Up: follow 4 principles to fit all UV Shells inside the Zero-To-One square: • Fix Seams: Fix irregularities on the sides of shells by splitting edges and sewing them to the other side. Split Shells that are meant to be different materials. • Group By Color: Put shells near each other which are meant to have the same material, like all the skin parts, all the pant parts, etc. • Prioritize: Scale larger areas that need more detail in their painting, like the face and any clothing that will show detailed designs or text. • Optimize: Adjust to better fill the space, leaving at least a 10-pixel gutter between shells. STAGE 4: EXPORT UVs: Object mode, Image > UV Snapshot. Set format to JPEG, size 2048x2048. Browse to set location and name. Hit [Apply]. STAGE 5: PAINT TEXTURES: Open the file in Photoshop, [Cmd]+[i] to invert, DoubleClick and name UVs. Set Blending mode to Multiply. Create two layers below: BaseColors and Details. [Shift] + rectangle Marquee to selections around color-areas, use Paint Bucket to fill. Paint details in the Details layer (hard brush 30%). Hide UVs, File > Save As a PNG. STAGE 6: APPLY IN MAYA: Create an AiStandardSurface material, add a file node to the Base > Color channel, add the color texture map. MiddleMouse drag onto mesh, hit [6].

6. Unwrapping Exercise A: Cylinder Mapping 1 Cylindrical mapping is like wrapping a paper around a cylinder, to project from all those directions. • Make Cylinders to represent a torso and an arm: • Create a Cylinder with 5 Height Subdivisions (about as detailed as a basic torso or limb). • [Cmd]+[d] to copy. Move and rotate the copy 90 degrees on Z, name it “Arm.” In Front view select the vertical cylinder, and in Face mode select and delete half the faces, name “Torso.” • In the Hypershade create a Checker map (colors, tile 20x20), apply to both, hit [6] to view. • Break off UV Menu. Open UV Editor. • Unwrap the “Torso”: • In the Persp view select the Torso length Faces and apply UV > Cylindrical map. Note the UV shape is warped and the checkers are uneven. The reason is the Cylindrical map is automatically centered on the selection, and this selection is only half of a cylinder. We need to move the gizmo to surround what would be the entire cylinder, but we cannot hit [w] or the map will just be committed. • Find and click the red T for gizmo transforms and in the Front view click the UV gizmo red (X) arrow. Move the Cylindrical mapping until the center of the gizmo is just slightly over the mesh center. Hit [w] to commit the map and adjust in the UV Editor.

7. Unwrapping Exercise A: Cylinder Mapping 2 • Unwrap the “Arm”: • In Persp view select Arm length Faces and apply UV > Cylindrical map. The Cylindrical map is vertical but arm is horizontal, so the UVs and Checkers are completely warped. • Find and click the red T. Select the Blue circle to activate the rotation gimbal ball. Drag the blue (Z) circle to make the gizmo surround the mesh, and drag the red (X) circle until the open side of the gizmo faces downward, and the white seam line is at the bottom of the mesh. NOTE: The Cylinder Mapping process is the most reliable method of unwrapping an organic form. The results are relatively rectilinear for easy packing in the zero-to-one square and the method works even if the geometry is not perfectly clean. Every part of the human form can be Unwrapped with Cylindrical maps except for the bottom of the shoe and the hands, which use Planar mapping.

8. Unwrapping Exercise B: Planar mapping Planar mapping is like projecting an image painted onto a sheet of clear plastic. The image is projected from a single direction straight into the form from that direction. • Create a Box. In Channel Box set Inputs: sizes = 10,2,10 and all subdivisions = 2. Name this box “Hand.” • In Hypershade create a Checker map (colors, tile 20x20), apply to Hand, hit [6] to view. Break off UV Menu. Open UV Editor. Note the initial UVs of the box are an upside-down T that does not match the shorter sides. • In Persp view select Hand. UV > Planar > Option Box. Set projection direction to the Y axis so it will be projected from above. Hit [Apply]. Note the UV editor now shows only the top of the Hand box; the sides appear as just lines under the outer edges. • In the Persp view, Edge mode, DoubleClick one edge on the middle line to select the full Edge Loop. In the UV Editor click Cut/Sew > Split. Note that Edge Loop turns white as the UVs there now sit along a Shell border. • UV mode, DoubleClick one UV to select a Shell and move that half away from the other. • Tools > Smooth and click drag [Unfold] to make the sides visible. We can change the tension on this Unfold by Splitting the corner edges and Unfolding again. • Select UVs for mirrored underside. Modify > Flip before Unfolding.

9. Unwrapping Exercise C: Unfold Mapping • Create a Cylinder with 5 Height Subdivsions (about as detailed as a basic torso or limb). • Apply Planar mapping to remove all seams. • Open the UV > UV Editor. Break off the Cut/Sew menu. • Define Seams: • On the 3D model in the Persp viewport, DoubleClick to select a vertical line on the cylinder. Add edges around the top and bottom circlers by holding [Shift] and DoubleClicking one edge on each. • Hit Cut/Sew > Split. Note white border lines that appear both on the 3D model and in the UV Editor 2D representation of that model. • Remove unintended seams by selecting the unintended split edges and Cut /Sew > Move and Sew. • UV Editor: in UV mode, DoubleClick one cylinder body UV to select the full Shell. Apply Tools > Smooth and drag on the [Unfold] option to open that Shell up. • Release tension if necessary by splitting an edge and re-Unfolding. NOTE: This process can be applied to any area of a clean mesh. For an arm we can select edges around the shoulder and wrist, then one long edge down the underside. Split and Smooth > Unfold. The results are not rectangular-ish, and so do not pack as neatly into the zero-to-one square, but can still provide solid UV shells for painting in Photoshop or Mudbox.

10. High Resolution Modeling and Texturing: Mudbox 1 Starting with the film Pirates of the Caribbean: Dead Man’s Chestand the game Chronicles of Riddick: Escape from Butcher Bay, artists have sculpted high-detailed meshes with millions or hundreds of millions of polys and projected that data back onto medium-poly models to use extensively in film and game render pipelines. The two most popular high –res programs are PixologicZbrushand Autodesk Mudbox. Zbrush started as a 2.5D tool and has evolved into an extraordinarily robust sculpting toolset used by companies and artists around the world , with an idiosyncratic interface. Mudbox has the advantages of being free for students and easier to learn, as the interface is based on Maya. The basic pipeline is (1) create a low-poly mesh in Maya, (2) unwrap UVs with no overlapping Shells, (3) Save and Save As an FBX file, open that FBX in Mudbox, (4) hit [Shift]+[d] to increase resolution, and sculpt/ paint, and (5) “step down” to export both the reshaped low-mesh and Normal map to (6) apply in Maya. Note: you are not required to use Normal Maps in your final project this term, but you have the option of doing so.

11. High Resolution Modeling and Texturing: Mudbox 2 A Normal is the vector perpendicular to the positon of a face or vertex. Lighting on a surface is defined by the direction of this Normal. A purplish Normal Map texture encodes surface normal of a 3D object captured into a texture. This then requires a material Shader that can unpack this data and interpret it as lighting information, thus creating the illusion of 3D detail.

12. High Resolution Modeling and Texturing: Mudbox 3 An ordinary Bump map is a grayscale image that a Shader interprets as lighting detail only in the Z-direction. A Normal Map encodes X, Y, and Z direction information using color, creating a much- enhanced illusion of depth. In Maya, this is added to the Bump channel in AiStandard using Tangent Space Normal In both cases, no change is made at the edge of the form; that would require a projection map on a super high resolution mesh, and the purpose of this process is to render high detail information on a mesh low poly enough to be used in an animation pipeline. Normal Map Tech explanation: https://www.youtube.com/watch?v=6_-NNKc4lrk And Polycount: http://wiki.polycount.com/wiki/Normal_map

13. Mudbox Interface and Tools 1 [A]. NAVIGATION: • [Alt]+ leftM = orbit, [Alt]+ MiddleM = pan, [Alt]+RightM = zoom • [f]= frame selected, [a]= frame all, [w]=wireframe [B]. LEVELS & LAYERS • [shift]+[d] = Add SubDivision Levels (try 4 levels for base forms, 2 more for details). [PageUp]/[PageDown] to step between levels. • Add a Sculpt Layer. It is locked to the current Level when you first sculpt on the object. Add more Sculpt Layers for varied areas or kinds of detail: infinite Mudbox Layers, at any SubD Level! • Name your Layers. • Top delete highest Level on selected object: [Shift]+[Backspace] [C]. TOOLS: • Use Wax, Foamy, and Sculpt tools to extrude detail, and [Ctrl] to reverse. [Ctrl]+ foamy makes a nice even cut line to define forms. Hold [Shift] to make any brush a Smooth tool. Try multiple Falloffs, and customize/store them. • Erase to remove content from current Sculpt Layer. • Brush Sizing: hold B and click-drag leftmouse, or tap [ and ] • Brush Strength: hold M and click-drag leftmouse, or tap [ ; ] and [ ' ]

14. MudboxInterface and Tools 2 [C]. TOOLS, Cntd: • FreezeTool, [Shift]+[i]= invert, [Shift]+[u]= unfreeze all. Use for masking edges. • Use Scrape with small stamp spacing for making edges hard/rough. Pinch to make edges sharp. Both good for defining edges. • Custom Tools: left side of tools, arrow/add tool. Name it. Starts with whatever settings are currently selected (so, duplicated another tool, and then can adjust all/advanced settings). • Try a custom Scrape with Random and 100% max pressure (so pen pressure has no affect), for random/harsh edges! • Hit # keys for first 9 tools (Windows/Hotkeys to customize). [D]. STENCILS TAB (lower right): • Click a Stencil to display it in the viewport. To transform, hit [s]. • Click the Sculpt tool and set Size to 5 and Strength to 0.5. • Click the circle triangle to add a new stencil. • Orbit the model to face the view and sculpt through the stencil to pull the design from the model. Hit [Off] Stencil when finished. [E]. VIEWPORT FILTERS (upper right side-tabs): • Try Cavity Ambient Occlusion, quality Best to better see detail.

15. MudboxInterface and Tools 3 [F]. SURFACING:In Mudbox, paint colors and photo-sources directly on unwrapped model. In Mudboxthe UV View only looks clean (or is visible at all) at SubD Level 0. (1) UV CONSIDERATIONS in Maya:https://www.youtube.com/watch?v=kKJoeEvzirw • Pack with 4+ pixel gutter. Avoid all overlap. • Size consistently (all checker squares same size. Can squash at joints). (2) EIGHT MAIN PAINTING BRUSHES (opacity=[m], for fine control use Steady Stroke, use Falloffs (tab on the right) to change brush shape): • Color: Paint (main), Airbrush (feathered), Pencil (sharp), and Drybrush (only paints on raised or depressed surface when used with tablet). • Stencils: Projection brush (stamp color data directly onto surface). To transform, hit [s]. • Utilities (like Photoshop): Clone, Erase, Color Picker (& others, like Blur). (3) TEXTURE LAYERS/CHANNELS: • Paint Layers are grouped by data type: Diffuse (color), Reflection Mask, Specular, Bump, Gloss, etc. Paint Layers are not SubD-level locked. • Use Layers to organize painting: wrinkles on new Diffuse layer, etc. Layers may be copied, merged, moved, hidden, deleted, exported to Photoshop for editing and refreshed in Mudbox to show changes.

16. MudboxInterface and Tools 4 [F]. SURFACING, Cntd:(4) PAINTING STEPS: Save a new copy of the file. You may want to merge as many sculpt layers as possible to free up memory. • Create a new Paint Layer on the selected geometry, set to Diffuse. Select the Paint Brush and in Parameters choose color, size, and strength. Paint a base color everywhere on the model and then add details in other colors. Paint color in Diffuse or alpha masks (black/white/gray) in other Channel types (Specular, etc). • Add a Stamp with Randomize turned on to your brush to create variation in your brush stroke when Painting and Erasing. • Use Stencils in Tray to add variation or pattern alphas to Paint Brush, or actual color with Projection Brush. Turn off in the tray upper-left. • Color is multiplied with base material color, so try different materials in the Material Presets Tray, like Porcelain (Fresnel Scattering Strength=0.7, reflection strength=0.17). • Use Drybrush to enhance fine geometry (does not work on Bump). • For projects with multiple objects (eyes, hair, clothes), give each their own Material: Create Menu/Material/Mudbox Material. In Object List rightclick to rename, rightclick object to Assign Existing Material and choose new material from options.

17. EXERCISE: Maya-to-Mudbox-to-Maya: High Res Coin 1 • MAYA: Create a cylinder: Radius = 10, Height = 1, Subdiv Axis = 20, Subdiv Height =1, Subdiv Caps = 1 • Doubleclick top and bottom circle Edges. Modeling Toolkit > Bevel: set Fraction =0.2 and Segments =2.  • Check how object appears smoothed by hitting [3], and then back to [1]. • Export selection as an OBJ. If the OBJ export option is not available, turn on OBJexport.mll under Window > Settings/Preferences > Plugin Manager. • MUDBOX: File > Open the OBJ. • Hit [Shift]+[d] or go under the Mesh menu to add Subdivision layers: 5-8 for a multi-million poly object. • Top view: Add the Coin face stencil, use basic Sculpt brush to impress detail. Turn off stencil and draw. • Side view: Add the side stencil and use the basic Sculpt brush to impress that detail. Turn off stencil and draw. • Use the grab tool to add a bit of distortion, so the shape is not so round and flat. Optionally, create a Diffuse layer and paint colors: paint a color everywhere, then add details. • [Page Down] to return to base level.

18. EXERCISE: Maya-to-Mudbox-to-Maya: High Res Coin 2 Use Stencils and Sculpt tool to stamp detail: Grab/Flatten/Smooth, then add Paint layers:

19. EXERCISE: Maya-to-Mudbox-to-Maya: High Res Coin 3 • MUDBOX (at Base Level): UVs & Maps menu > Extract Texture Map > New Operation. Choose Normal Map. Settings: • Extraction Options > Target Models = [object] level0, Source Models = [object] level7, set Method = Subdivision • Image Properties > Antialiasing = 2X • Normal Map Output > Compatibility = Maya, Coordinate Space = Tangent • Output Options > Map Type = Texture, Bits Per Channel = 16 bit, hit [...] to set location, name, and type: 16 bit TIFF • At bottom, hit [Extract]. • Still at the Base Level, export the mesh (which currently shows the effect of the Normal map): In the Select/Move Toolstray, choose Objects and click on the mesh to select it. File > Export Selection to export a new OBJ. • MAYA: Import the mesh. Mesh Display > Soften Edge. • Create and apply an Arnold AiStandardSurfacematerial. Geometry > Bump to add a File node. In the Bump node change 2D Bump Attributes > Use As > "Bump" to "Tangent Space Normal". In the File node add the Normal map. Add an Arnold > Lights > Skydome and view in the Arnold Renderer • Material: add color files, and try chrome preset with gold/yellow reflection color.

20. EXERCISE: Maya-to-Mudbox-to-Maya: High Res Coin 4 Export at the mesh at a low SubD level, either 0 or 1. When the Normal Map is extracted, it will appear on the mesh at these low levels. In Maya, import the adjusted mesh and apply an AiStandardSurface material. The Normal Map goes into the Bump channel with the Use As function set to Tangent. Add an Arnold Skydome light and view in the map in the Arnold Renderer.

21. 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) |_____> LinoleumFloor.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.

22. 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 dayto upload your work. To guard against crashes and loss of work, please Save and Save As a new file everyhour (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.