Tutorial: Rusted Golden Idol

From ZBrush Info

In this section we’ll put the theory behind ZBrush’s 2.5D painting techniques to work.

In the last section, we learned the basic principles behind 2.5D painting. Now we’ll apply those principles to create a simple but fun project.

Contents 1 Create the Idol 2 Paint the Model 3 Lighting and Materials 4 Create the Idol's Shadow 5 More Materials

Create the Idol

We’ll begin by creating the idol out of simple primitive shapes. Color and material will then be used to paint the rust onto it. Lastly, we’ll create a background and use some ZBrush trickery to paint the shadow.

• Press Preferences:Initialize ZBrush to return to the startup state.
• Select the Ring3D tool.

• Select the Basic Material, and a Brown color.

This material will be modified later to suit our needs. We’re using it instead of the default Fast Shader because the Basic material has many more modifiers.

• Set the Tool:Initialize values.

Use SRadius 39, Coverage 180, Scale 1, Twist 0, SDivide 32, LDivide 64, and ITwist 0. Every native ZBrush object is parametric in nature. This means that you can use the Initialize menu to set various parameters that influence the object’s shape.

• Draw the object on the canvas.
• Activate Rotate.

This turns on the rotate gyro.

• Rotate the half ring so that it curves up.

Markers must be placed while the current object is active. Once you have switch to a new tool, it is too late to place a marker without redrawing the object.

Also, only one marker can occupy any part of the canvas. If you try to place a marker too close to another one, the first will be replaced by the new one.

When close to the desired rotation, press Shift to snap it the rest of the way.

• Activate Move.

• Position the ring near the top center of the canvas as shown.

Use Scale if necessary, to match the illustration.

• Press Transform:Place Marker.

You’ll see a small animation as the marker flies from the button to the center of the object on the canvas. Markers are a very powerful feature of ZBrush. They are able to remember many details about a 3D object, including its position on the canvas, scale, orientation, material, color and more.

We’ll use this marker to assist with positioning the rest of the 3D elements in the scene.

• Select the Sphere3D tool.

If you receive help message, select “Switch Now.”

• Draw it at one end of the arc on the canvas.
• Activate the gyro.

• Position this small sphere so that it is embedded in the Ring object.

• Draw another sphere.
• Activate the gyro.
• Set Tool:Initialize:Coverage to 180.

While the gyro is active, the object is in a transformable state. This means that adjusting the Initialize settings will also affect the sphere on the canvas, making it into a hemisphere.

• Use Move, Scale and Rotate to flatten out the hemisphere and position it as shown.

• Press Layer:Dup to clone the layer.

This new layer will be an exact copy of the first.

• Press Layer:Flip H to flip the layer horizontally.

• Move the duplicated layer so that the two arcs merge.

You can use the Displace H slider to move the layer, or hold down the tilde (~) key and click+drag within the canvas.

• Merge the layers by pressing Layer:Mrg.

This combines the current layer with the one to its left (the original one). The result is one layer again. Always be sure that Zadd and Mrgb are active before merging layers. Otherwise, you can get strange effects.

• Duplicate the layer again and flip it vertically.
• Use Displace V to move the layer down, forming legs.

• Merge the layers.
• Select the Sphere3D and move the pointer so that it is where the marker was placed.

The marker will appear when you get close to it, and will enlarge when your pointer is directly on top of it.

• Click the marker.

The sphere will be drawn with the exact scale, orientation and position of the ring.

• Use the gyro to scale it smaller.

• Select the Cylinder3D and click the marker to draw it.
• Use the gyro to rotate and move it into position. Use scale to lengthen it.

Remember that clicking on the intersections of the gyro makes it possible to constrain your transformations. For example, the yellow intersection is used to lengthen the cylinder without changing its diameter.

• Add several Ring3D objects.

The one around the head is added by clicking the marker and then scaling and rotating the ring appropriately. Snapshot was pressed to copy the ring at its current position before moving the ring down the body and scaling/rotating it. The ring was snapshot three times here before moving and rotating it into place for the arm band and ankle. Note that the right side is left alone.

• Duplicate the layer, flip it horizontally, and move it into position.

• Merge the layers.

Paint the Model

• Create a new layer for the background.

While the simplest way to color the background is to change the Document:Back color, we will want to paint on ours. To make this possible, we will use a different technique involving a second layer and a 3D object.

• Select the Plane3D tool.

• Select the Flat Color material.

This material is unaffected by the rendering engine, and so will not receive shadows from it. While ZMode shadows with good Rays and Aperture settings will produce an excellent shadow, we have chosen to paint the shadow manually in order to illustrate other ZBrush features.

• Draw the plane on the canvas and use the gyro to scale it to fill the screen. Also, move it back behind the idol.

Remember that you can change an object’s depth while Move or Rotate are active by clicking and dragging anywhere on the canvas surrounding the gyro.

• Select alpha 27 and the Simple Brush.

• Rotate the alpha by pressing the Alpha:Rotate button.

• Select the Drag Rectangle stroke type.

This stroke will allow us to paint a single instance of the alpha.

• Choose a darker color, turn off Zadd, and paint a stroke on the canvas so that the gradient fills it completely.

You can use the gyro after drawing the gradient to move and scale it if necessary.

• Switch back to layer 1 so that we can paint on the idol.
• To begin painting the rust, use the Simple Brush and alpha 23.

• Using the Drag Rectangle stroke and various shades of color, paint multiple copies of the alpha all over the idol.

You could also use the Spray stroke type for parts of this. Since the background is on a different layer, it is completely unaffected by these strokes. With ZBrush, there is no need to “color within the lines.”

• Change the Draw:Width to 50%

This changes the width of the alpha, which in turn will affect the strokes being painted on the canvas.

• Continuing to vary the colors, add still more rust to the idol.

Lighting and Materials

• Adjust the direction and intensity of the primary light.

To adjust the direction, click and drag on the small square located on the thumbnail. You will be able to see the lighting update on the canvas in real time. Set the intensity to 1.22.

• 
  The next step is to adjust the material properties to look more like rusted metal.

Use the settings shown to the right. Diffuse should be 86 The Diffuse Curve should be modified slightly, and given about 50% noise. Also pay attention to Specular to modify the shininess of the metal and Color Bump to make it rougher.

The material now looks a lot more like rusted metal, but it’s still missing something. Rusted metal doesn’t only contain variations in color, but also variations in specularity, diffuse, reflections, etc.

• Press the CopyMat button located above the material modifiers.
• Select another material such as Fast Shader 5.
• Press the PasteMat button.

This replaces the Fast Shader 5 material with a duplicate of the Basic material.

• Set the material’s Diffuse to 60.

This will make it possible for us to see where we are painting this new material because it will stand out against the existing one.

• Activate M on the top shelf.

This instructs ZBrush to ONLY paint with material. Colors and depth will not be changed.

• Paint the new material in scattered places across the idol.

• Because this material is a copy of the original, it still has the same rust quality that we had built previously. This is a real time saver. It’s simply darker than the first because we adjusted the Diffuse before painting the new material.

• Adjust the other material modifiers.
  • Raise the specular setting.
  • Adjust the Diffuse Curve.
  • Add a little noise to the material itself, etc.

• At this point, tweak the colors on the idol a bit by switching to Rgb and painting with just color.

For purposes of this manual, “Tool” always refers to an item found in the Tool palette.

Create the Idol's Shadow

There are several methods by which a drop shadow can be added to the scene. As previously mentioned, we could simply tell the rendering engine to render shadows. The drawback to that is due to the fact that our background is a vertical plane located just behind the idol. Rendered shadows would give it away immediately. Since we wish to give the impression that the idol is standing on a vast plane, we’ll use a different technique.

• Select the MRGBZGrabber tool.

This complicated-sounding tool is used to grab a kind of snapshot of the canvas. It can capture the materials (M), colors (RGB), or depth (Z) hence its name.

• In the Tool:Modifiers, turn Auto Crop off.

With Auto Crop active, the grabbed area would automatically be cropped to the size of the objects on the layer. We want to capture the entire canvas, instead.

• Click and drag on the canvas to capture the entire scene.

Two things will happen when you release the mouse. A capture of the canvas will be placed in the Texture palette. At the same time, a depth map of the canvas will be placed in the Alpha palette.

This alpha is a precise representation of the canvas with the grayscale values representing relative depths. White is the highest depth while black is the lowest.

• Press Alpha:Make St to convert the alpha into a stencil.

The stencil will immediately be activated on the canvas. Dark areas can be painted through, while light areas will block paint.

• Activate Stencil:Elv.

This displays the stencil as an outline, making it easier to see the rest of the scene. It does not change the stencil’s effect at all.

• The stencil is too small. Press Stencil:Stretch to match the size of the stencil to the size of the canvas.

• Hold down the Spacebar to activate the stencil’s Coin Controller.

This controller will appear at the pointer location, and has several controls built into it.

• Click V on the controller and drag to reduce the height of the stencil.

• Release the Spacebar to dismiss the controller.
• Select the background layer from the Layer palette.

• Use the Simple Brush and a dark color to paint the shadow through the stencil.

• Once the shadow has been painted, you can turn off the Stencil:Stencil On switch.

• Use the Blur brush (found in the Tool palette) to soften the shadow edges.

More Materials

• Return to layer one (the idol layer).
• Select the Colorizer1 material.
• With Draw:M active, paint this material onto the figure.

• Modify the material properties.

This material has two shader channels that must be modified. You switch between them using the S1 and S2 buttons at the top of the modifiers. Match the images at the right.

• Add a few more brush strokes of color, only to complete the scene.