Tutorial: Learning Paint Effects
In this tutorial, you'll try some of the Paint Effects options on a NURBS surface you create:
Start with a blank, empty workspace in Maya. Tap the spacebar with the mouse over the Perspective view to switch to the Four View mode. Create a Directional light (Hotbox | Create | Lights | Directional Light), and set its Rotate X to 90 in the Channel Box. Under the light's Shape node in the Channel Box, enable the Depth Map Shadows option by typing a 1 or On and pressing Enter. Choose Create | NURBS Primitives | Cone | option box, and reset the settings in the Cone Options dialog box. Set Radius to 300 and Height to 100, and then click the Create button. Press Shift+F to "fit all" so that you can see the entire cone in all four views.
If the Perspective view does not display the cone or it looks chopped off, it's likely a problem with the perspective camera's clipping plane. To fix this, choose View | Camera Attribute Editor in the Perspective view to open the perspective camera's attributes, and set the Far Clip Plane to 10000.
Set the cone to display in high detail (hotkey: 3), set the Perspective view to Shaded mode (hotkey: 5), and tap the spacebar to return the Perspective panel to full screen. To make the cone paintable, select the cone, and click Hotbox | Paint Effects | Make Paintable, as shown in Figure 2.
Figure 2 The first step in Paint Effects: Making an object paintable.
Switch to a Paint Effects panel (hotkey: 8). If you see a blank white panel, RMB-click in the panel and choose Paint Scene. On the Shading menu, make sure the options for Textured and Use All Lights are enabled. Open the Visor (hotkey: Shift+V). Click the Paint Effects tab, expand the Brushes folder in the left-hand column if necessary, select the Flowers folder, and then click Daisy. Minimize the Visor.
You browse the swatches in the Visor just as you do in any Maya dialog box: Alt+MMB to pan and Alt+LMB+MMB to zoom.
Hold the cursor over the cone and see if the Paint Effects Tool cursor appears. The daisy's default size is quite small compared to the cone. To increase the brush's Global Scale attribute, you could press and hold the b key while clicking and dragging to the right on the cone. However, for this tutorial, set it to 40 by opening the Brush Settings dialog box (hotkey: Ctrl+b) and changing the Global Scale value. Close the dialog box, and draw a stroke on the cone, near the outer edge and about a third of the way around the cone. You should see daisies appear on the cone. Even though the last daisies you paint are only half-created when you release the mouse button, they finish growing to their full size because of the Tube Completion setting.
In the Channel Box, under Shapes, you'll find the settings for the daisy stroke you created. The Sample Density attribute specifies how many daisies appear for a given length of the stroke. Try setting it to 2 or 3 to see the result.
How fast or slow you draw the stroke can affect the density, too. Because Paint Effects uses "sampling" when creating a stroke's underlying curve, a stroke drawn quickly has fewer samples and thus looks less dense than a stroke drawn more slowly.
Bring up the Visor again, and select the Sunflowers brush in the Flowers folder. Note that you need to adjust the brush's Global Scale setting when you switch brushes because the brush settings (the "template brush") change when you select a new brush. Open the Brush Settings dialog box (hotkey: Ctrl+b), and set Global Scale to 20. Notice that the brush size isn't necessarily related to the plant's overall size. The brush tip is small, but the sunflowers you paint are much taller than the daisies. You might want to make a few test strokes that you can undo later if needed (hotkey: Ctrl+z) to fine-tune the Global Scale settings. When you're satisfied with the plant's size, draw a stroke of sunflowers above the daisies.
If the Paint Effects panel is partially covered by another dialog box while it's rendering the stroke, the image might not be displayed in the area that's covered. Click the Redraw Paint Effects View button to regenerate the view if needed.
Use Alt+LMB to orbit the Paint Effects view. Notice that the painted objects are reduced to lines during the orbit. Select the Roses brush in the Visor, and set the Global Scale to 28 in the Brush Settings dialog box. Next, increase the brush width by pressing Shift+B while LMB-dragging to the right. The Paint Effects brush cursor will increase as though you had raised the global scale, but when you paint, you'll see that the roses are the same size as before, but appear over a broader area. Paint a new stroke above the sunflowers. Then set Sample Density in the Channel Box (under Shapes) to 3, and you'll see that the roses look denser and fill up more of the stroke area you drew, as shown in Figure 3.
Figure 3 Three rows of flowers.
Exit Paint Effects by switching back to the Perspective panel (Panels | Perspective | Persp). The flowers' wireframe representation is noticeably thinner than it looked in Paint Effects. To see more lines for the roses, select the Roses stroke, and set the Display Percent to 100 in the Channel Box, under Shapes. If you accidentally deselect the Roses stroke, open the Outliner (Window | Outliner) and select the strokeRoses1 item.
Orbit the Perspective view until you're looking across the cone, up close to the flowers, as shown in Figure 4. In the Perspective view, choose View | Camera Attribute Editor, and in the Camera Attribute Editor, set the Background Color under the Environment section to white so you can see the paint effects you added more easily. Close the Attribute Editor and render this view by clicking the Render button or choosing Hotbox | Render | Render Current Frame. Notice that the flowers cast shadows and seem thicker than the wireframe would imply.
Figure 4 The rendered view of the three rows of flowers.
Using Paint Effects is fun and usually quite straightforward. Remember that Paint Effects are rendered separately as a post-procedure, and then are automatically composited into the rendered frame. You can see this during rendering, when Paint Effects don't appear during the normal rendering, and then pop up at the end of rendering after some delay.
You've had a chance to try out some of the Paint Effects features and create some complex scenes with relatively little effort. Some of the methods you've learned include:
Preparing objects for Paint Effects: You can't paint on an object unless it's a NURBS object and has been made paintable during the current Maya session.
Browsing and choosing a brush: Maya offers a broad collection of brush presets in the Visor.
Editing brush settings: You've learned how to change the way the brush paints and modify the look of the stroke after painting it.