CGS 3220 Lecture 4 Shaders, Textures, and Light

Transcription

1 CGS 3220 Lecture 4 Shaders, Textures, and Light Introduction to Computer Aided Modeling Instructor: Brent Rossen

2 Overview Working with the menu-less UI Working with the Hypershade Creating shading groups Texture mapping an object Creating basic lighting Rendering a single frame

3 Getting Serious So far we ve been making use of numeric input fields, menus, and other UI elements. With this lesson, let s pretend we re hard core and hide all the menus while relying on the hotbox and hotkeys. Open our file from last time Resave it as litgarage.mb

4 Turn off all menus After we hide the menus, to access them we ll hold spacebar to evoke the hotbox Hold spacebar now, click on Hotbox Controls Select Window Options Show Main Menubar: off Show Pane Menubars: off (windows only) Display > UI Elements > Hide UI Elements Now we ve got a much larger and cooler looking workspace. Which should allow us to forget the computer and focus on Modeling and Animation.

5 Menu-less Navigation Change the Panel Organization Evoke the hotbox by holding the spacebar Click the area above all the menus to apply the north Marking Menu Select Hypershade/Render/Perspective Hypershade: where you build shaders Render: where you see the output You can drag the divisions between the windows to change the size of each window

6 Menu-less Navigation Cont Each of the four cardinal directions in the hotbox has its own Marking Menu You can edit the contents of the Marking Menus from Window > Settings/Preferences > Marking Menus Open the attribute editor Display > UI Elements > Attribute Editor or Ctrl+a Use the attribute editor to update shading network attributes. You can also access most of the same channels as are available in the channel box

7 Important Hotkeys Spacebar: hotbox/window popping Ctrl+a: Show/hide attribute editor F: frame selected A: frame all Q: pick tool W: move tool E: rotate tool R: scale tool T: show manipulator tool Y: invoke last tool G: repeat last command Alt+v: stop/start playback Alt+shift+v: go to first frame For the complete list or to change hotkeys: Window > Settings/Preferences > Hotkeys

8 Shading Networks To add colors and texture we ll use shading networks Shading Network: contains materials, textures, lights and geometry to create a desired look. The Hypershade panel has: Create Bar: allows you to create material nodes Hypershade Tabs: list all nodes in the scene Work area: where you can look more closely at a particular shading network s graph

9 Hypershade We ll use the hypershade to create materials that define the look of the boxes, shelves, lamp, door, and door knob.

10 Create Blinn RMB in the materials area and Create > Materials > Blinn Or click the checkered button to open the create tab, and select blinn from there You can see that a blinn shading node is added to the materials area Blinn: a material node that gives you special control over a materials highlights. Very good for Metals and other shiny objects.

11 Assigning the Blinn Double click the blinn node, and the attribute editor will pop up (or ctrl+a). Rename the blinn to lampmat Let s edit the color attribute first. Double click the gray box next to color in the attribute editor. Choose any color you want, and hit accept MMB+drag the lampmat onto your lamp, or select the lamp, RMB the lampmat and Assign material to selection

12 Softer Lamp In the perspective window, notice how the lamp appears very polygonal, perfectly showing every edge. To create a slightly smoother effect, without adding geometry, we ll just turn on Soft Edges. With the lamp selected, Edit Polygons > Normals > Soften/Harden You can see now that we have smoother edges, try different angles from the options box

13 Wire Material RMB in the work area > Graph > Clear Graph If there was anything in the work area, it would be removed Create a Phong material, change the color to black Phong mats have a plastic look to them Change the name to wiremat Select the wire and RMB wiremat > assign material to selection Assign Material to selection can be used with multiple selected objects

14 Bulb Material Create a Lambert material, with a yellow color and rename it bulbmat Change the incandescence color to dark yellow Lambert Materials: good for anything that doesn t have strong specular highlights, such as clothing, paper, and other fibers. Adding incandescence flattens the material and makes it appear to glow, though it does not actually give off any light.

15 The Bulb Create a basic NURBS sphere, rename it bulb and place it in the lamp Assign the bulbmat to the bulb

16 Creating a procedural texture Map Click the clear graph button (looks like an eraser) Let s give the boxes a texture Create a Lambert and name it boxmat Create > 2d Texture > grid MMB drag the Grid icon onto the boxmat Select color on the box that pops up Click the Rearrange Graph button

17 Crate Material Assign boxmat to one of the crates Activate the perspective window, Hotbox > Shading > Hardware Texturing (hotkey 6) Warning: be careful with hardware texturing, it can significantly reduce machine performance Double click the grid1 node, change the line and filler color to whatever you want

18 Changing the Mat Click the place2dtexture1 tab on in the attribute editor Change Repeat U and V to 2

19 Display the whole shading group With the grid selected, click on Input and Output Connections You can MMB wheel to zoom in and out, most of the same controls that work for the main view, work for all other windows Press a to frame all lambertxsg is the connection from the boxmat to the crate

20 Creating a file texture map You ll often want to use a texture file instead of an internal procedral texture object These can be created using Photoshop, Gimp, or any other 2d package Create a Phong rename it cratemat Open the attribute editor with cratemat selected Click the Map box next to the color attribute

21 Assign Texture Click the folder button, and select your image Be sure your image is already in the sourceimages folder so you can find it easily Apply cratemat to one of the crates If you make changes to the image outside of maya, just hit the reload button on the file texture Normally, textures won t look good at first, but we got lucky this time

22 Test Render Since the perspective window size can change dramatically, let s use the resolution gate to see what will actually be rendered Activate the perspective window > Hotbox > View > Camera Settings > Resolution Gate Dolly in so that the image is well framed. You ll probably want to be looking towards the boxes to get everything in view RMB the render window > Render > Render > persp

23 The Rest of the Room Our shelves are still gray, so let s apply a texture to them Create lambert, rename shelfwood Map a file texture, select a wood texture (find it next to this lecture on the web page) Assign shelfwood to the shelves The door is just a red blinn, and the handle is a yellow-orange blinn Render again, click the clapboard button

24 Default Light Test Render

25 Add a bulb light We re still using the default lighting, which looks very flat Create > Point Light Rename it lamplight, put it inside the bulb Open the shadows tab, check use depth map shadows Render, why don t we see anything but the bulb? Select the bulb, open Render Stats, uncheck cast shadows

26 Test Render 2

27 Add a floor light That s better, but it doesn t show us nearly enough. The lamp shade is blocking everything. Let s put another light on the floor to simulate reflected light. Turn the floorlight intensity down to.3, Turn on shadows Turn the lamplight intensity to.5 Now we have some very dramatic night-time shadows

28 The Lit Room

29 Conclusion Save your scene! We ve now covered the basic concepts of texturing, lighting, and rendering. We went over materials, procedural textures, file textures, lights, and rendered a single frame to preview the look of the Shaders and lights. Next time, we ll go over the basics of animation.