Introduction to 3D Art and Animation Lesson D (week 4): Useful Modeling Techniques and Intro to UV Mapping

Useful Modeling Techniques 1 NURBS Curves: Revolve: Revolve can be used to quickly create objects which are round and symmetrical in 360 degrees, like a vase, bowl, or lightbulb. In the Curves/ Surfaces Shelf, choose the EP Curve Tool. In the Front Viewport, click to draw half a cross-section of the desired form. So, for a vase, draw half of a 2D vase from the outside to the inside, starting at the bottom, leaving the center empty. Finish the form by hitting [return]. If you need to adjust the form after hitting [Return], RightClickHold for Control Vertex, select around and move/scale/rotate the points. In Object Mode, Modify > Center Pivot and Hit [d] to move the pivot to where the center of the full object would be. Modeling Module Surfaces menu > Revolve. You can select the new form and drag it away from the original curve. You can also convert the result to a polygon model: find Modify > Convert > NURBS to Polygons and choose the Option Box. Keep “Type” at Quads, but consider switching “Tesselation Method” to General in order to set U and V Numbers to get a cleaner final surface grid (try 20 each).

Useful Modeling Techniques 2 NURBS Curves: Loft: Loft can be used to quickly create Curved topology based on multiple cross-sections, particularly good for hanging cloth, like curtains. In the Curves/ Surfaces Shelf, choose the EP Curve Tool. In the Top Viewport, click to draw the bottom of a curtain as it would touch the floor: multiple “wave” curves. In the Persp Viewport, hit Cmd+[d] to duplicate twice and drag those copies up to be the midpoint the top of the curtain. In the top curve move the outward control points down to be the hang of the drape. In the midpoint scale the CVs closer together in depth to allow the curves to grow at the bottom, or in width to tie the curtain to a side. In Object Mode select the bottom curve and [Shift]+click the middle and then the top, so all are selected in order. Modeling Module Surfaces menu > Loft. You can select the new form and drag it away from the original curve. You can also convert the result to a polygon model: find Modify > Convert > NURBS to Polygons and choose the Option Box. Keep “Type” at Quads, but consider switching “Tesselation Method” to General in order to set U and V Numbers to get a cleaner final surface grid (try 20 each).

Useful Modeling Techniques 3 Extrude Along a Spline: Polygon Extrusion can be made to follow a spline curve. This can be useful to make power cords, wires, pipes, and hoses. In the Curves/ Surfaces Shelf, choose the EP Curve Tool. In the Top Viewport, draw the spline path you want for your extrusion. Hit [Return] and move it so the start of the line you created is very close to the polygon face you want to extrude. In the Persp Viewport, select the Polygon object, and in Face mode select the face. [Shift]+select the EP Curve and hit [Extrude]. Increase the Extrude Divisions to make the extrusion follow the curve.

Useful Modeling Techniques 4 Booleans: Boolean operations allow us to merge two forms (instantly removing the interior geometry), or subtract one form from another. Booleans must be performed on clean, modular geometry or the result can be null (object disappears): no interior/broken geometry. Create two primitive objects and position them so they intersect. In the Modeling module, choose Mesh menu > Boolean > Union to merge these two objects into a single form and automatically remove all intersecting geometry. OR choose Mesh menu > Boolean > Difference to cut the second selected object out of the first, building the inverse of the second surface into the hole. Follow up any Boolean with cleanup: Edit > Delete by Type > History Edit Mesh > Merge all vertices to remove any doubled verts Use Connect to make quads to the new geometry

Useful Modeling Techniques 5 Detach/Separate: Breaking off part of an object takes two functions: Select the faces to be broken off. Edit Mesh > Detach, so all vertices along the seam (between selected and non-selected) are doubled. Modeling Toolkit (or Mesh menu) > Separate (to break the faces into a new object) In Object Mode, click in an empty area of the viewport, click back on the new broken-off piece.

UV UNWRAP: Telephone Pole Exercise A Download the provided Unwraping_TelephonePole.zip containing a Maya file and three full .PNG textures for Color, Bump, and Specular maps. STEP 1: CREATE MAYA MATERIAL Open the Hypershade, create a Blinn Shader. In the Edit Parameters panel find Color, click the checker square, add a File node, click Manila envelope and add TelephonePole_color.png. MiddleMouse drag the material from your top library onto each of the 5 meshes (stop sign, pole, and three climbing hooks) in the Viewport, hit [6] to view. STEP 2a: ARRANGE UVs IN UV EDITOR In the Modeling module, Open UV > UV Editor. Each object in the scene has default UVs that can be transformed to fit over the provided texture maps: Select the three climbing hook meshes in the scene to see their default UVs and the color texture in the UV Editor. RightClickHold to choose UV mode, select around the UVs and move [w] and scale [r] them into the black rectangle in the upper left corner of the color image. Select the stop sign mesh in the scene. In the UV Editor RightClickHold to choose UV mode and select the top hexagon shell by double-clicking one of its UVs. Transform it (Move/Rotate/Scale) to fit over the front stop sign art. Select the bottom hexagon and transform it to fit over the grey back art. Select the center UVs and non-uniform scale (squash) into a thinner line, and fit in an empty gray area.

UV UNWRAP: Telephone Pole Exercise B STEP 2b: ARRANGE UVs IN UV EDITOR Select the telephone pole mesh in the scene. In the UV Editor Face mode select the bottom circle and hit delete to remove those polygons from the model. Select the top circle and scale smaller to fit over the wood art on the left side. The pole itself can be manipulated to be the width of the wood art and about twice as tall as the image, so it tiles. NOTICE that the art does not tile evenly– the relative distances between the horizontal lines of the UVs in the UV Editor do not match the relative distances between the horizontal lines on the mesh, so the art appears to stretch or squash. We need to re-map this pole geometry. In the UV Editor Face mode, DoubleClick a face on the pole to select the full face shell. In the Viewport, apply UV menu > Cylindrical map. This applies a curved mapping around the selected faces. The curve is on the Y-axis (vertical) by default, which works well for us here. In the UV Editor hit [r] for scale, RightClick for UV mode, DoubleClick a UV on the pole to select the shell, transform so it is the width of the wood art and about twice as tall. Your mapping is complete. Try applying the bump (with a reduced bump value) and specular maps to the Blinn material.

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.

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.