Introduction to Computer Aided Modeling

Instructor: Brent Rossen

CGS 3220

Lecture 4

Shaders,

Textures,

and Light

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

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

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.

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

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

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

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

Hypershade

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

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.

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

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

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

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.

The Bulb

Create a basic NURBS sphere, rename it bulb and place it in the lamp

Assign the bulbMat to the bulb

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

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

Changing the Mat

Click the “place2dTexture1” tab on in the attribute editor

Change Repeat U and V to 2

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

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

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

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

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

Default Light Test Render

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

Test Render 2

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

The Lit Room

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.