Layer Palette

From ZBrush Info

1 About Layers
2 Controls

About Layers

ZBrush lets you work in a number of different layers in a single document. Each layer is the same size as the canvas, and contains pixols independent from those on other layers.

In most drawing programs that offer layers, a pixol is visible only if it's in the uppermost layer, or if it's in a lower layer and all pixols above it (that is, in higher layers) are transparent. In ZBrush, the visibility of any given pixol depends only on its depth, or Z-axis position, compared to the depth of pixols at the some position in the other layers. For example, you could have one layer with vegetation; trees in the background (far away), and shrubs in the foreground (near). If you have characters in another layer that are at an intermediate distance, the characters would appear to be in front of the trees but behind the shrubs.

By default, ZBrush starts with a single layer. You can add and delete layers, work in any existing layer, change the depth of pixols on a layer, and combine and hide layers. As documented in the Material palette description, you must use layers for transparency to be visible in the document.

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Working with Layers

The Layer palette shows a thumbnail for each layer. You can have up to sixteen layers.

Below is an image of a canvas containing three shapes on three different layers, and the corresponding display in the Layer palette thumbnails section. As you can see, the parts of objects that are visible depend solely on whether there is something in front of them or not.

Three objects on three different layers are visible according to how close their pixols are to the viewer.

The layers thumbnail area shows which layer each object is on.

The active layer is marked with a yellow outline; simply click on an inactive layer to make it active. In addition, visible layers are marked with a yellow triangle in the upper left corner of their thumbnail. To toggle layer visibility on or off, make it the active layer, and then click again on it to change its visibility. However, the active layer is always visible, regardless of its visibility setting.

Note: To toggle the visibility of all layers, Shift-click the active layer.

In the figure above showing layer thumbnails, you’ll notice that the thumbnails for inactive layers are cropped to show only the non-blank section of that layer; this makes it easier to see what is on that layer. The thumbnail of the active layer is not cropped, so that you can see its contents relative to the overall canvas.

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Object Orientation with Multiple Layers

Normally in ZBrush, when you draw a 3D object on top of a non-blank portion of the canvas, the orientation and depth of the object is set in relation to the orientation of the canvas underneath the object. This remains true as you move the object around, to make it easy to, for example, position cylinders representing bolts orthogonally to the surface of a sphere representing a steam chamber. In a multilayered document, this orientation is always done with respect to visible pixols, regardless of which layer they are on.

Note: The Picker palette contains many options for setting or controlling orientation, depth, and other properties of an object as it is drawn on and move around the canvas.

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Quick Layer Selection

You can quickly make another layer active without using the layer thumbnails. Press and hold the tilde key (~), and in the document click a pixol that belongs to the layer you want to activate. This feature can be turned off using the Layer:Auto Select switch. Default = on.

Note: After activating a layer with Auto Select, release the tilde key before you start to draw. If you drag the mouse in the active layer with the tilde key held down, you scroll the layer instead of drawing.

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Controls

Clear: Deletes all pixols from the current layer.

Fill: Fills the current layer with the current color. Or, if a texture is active, Fill uses that texture instead, resizing it as necessary to fill the canvas.

Bake: Converts all pixols in the active layer into base colors. The pixols retain their position and orientation information. All colors generated by material, shading and render effects are also retained, and the pixols become converted to the Flat Color material.

You can see how this works by starting ZBrush, and then following this procedure:

Add a sphere.
In the Render palette, click the rightmost icon (Flat Renderer). The sphere's shading is no longer visible.
Return to the Preview Renderer to make the shading visible again.
Open the Light palette and move a light source (the gray square over the large sphere) while observing how the shading changes.
Bake the layer.
Move the light source again. The shading no longer changes, because the default FastShader pixols have been converted into base colors in the Flat Color material, which doesn't respond to lighting changes.
Activate the Flat Renderer again. The shading remains, because it has been "baked" into the document's base colors.

B Blend: (Bake Blend Amount.) Sets the amount of blending between shaded and unshaded pixols when Bake is performed. This numeric setting determines the percentage of each shaded pixol to be used, and the setting subtracted from 100 determines the percentage of each unshaded pixol to be used. Take, for example, one pixol of a shaded white sphere. The pixol has a shaded pixol grayscale value of 90, and an unshaded pixol value of 255. If you bake the image at 80% B Blend, the software multiplies 0.8 times 90, and adds it to 0.2 times 255, ending up with a pixol grayscale value of 123.

In the following illustration, a sphere is shown with shading (left) and without (center). After baking the layer at 80%, the resulting unshaded image (right) is darker than before, but not quite as dark as the original shaded image.

Shaded

Unshaded

Baked

Note: Baking a layer at any percentage less than 100 leaves the original shaded pixols (materials, etc.) as they were, and this is combined with the baked image, so the rendered image is usually darker than before. This way, you can set a certain lighting setup, material, etc., bake a percentage of that into the base colors, and then continue modifying lighting, materials, and so on, combining new effects with the original setup.

Flip H: Flips the layer contents horizontally.

Flip V: Reverses the layer contents vertically.

Displace H: Lets you move the layer contents horizontally using the mouse slider, or numerically from the keyboard. If you use the mouse slider, you must release the mouse button to complete the displacement.
You can also move the layer contents horizontally and vertically by holding the Tilde (~) key and dragging in the document window.

Displace V: Lets you move the layer contents vertically using the mouse slider, or numerically from the keyboard. If you use the mouse slider, you must release the mouse button to complete the displacement.
You can also move the layer contents horizontally and vertically by holding the Tilde (~) key and dragging in the document window.

W: (Wrap Mode.) When on, Wrap Mode causes the pixols in a layer to be moved horizontally or vertically to "wrap around" to the other side. For instance, if a layer contains a sphere and you move the layer so the sphere moves past the right side of the document, it reappears on the left side. When off, pixols moved past the edge of document are lost. Default is on.

Displace Z: Lets you move the layer contents in and out (in the 3rd dimension) using the mouse slider, or numerically from the keyboard. You can also move the layer contents on the Z-axis by holding the Tilde (~) and Alt keys and dragging vertically in the document window. Dragging upward moves the layer away from you, and downward moves it toward you.

Delete: Deletes the active layer from the document. This operation cannot be undone. If the document contains only one layer, Delete has no effect.

Create: Adds a new layer to the document in the slot immediately to the right of the current layer. The new layer is automatically activated.

Dup: Adds a duplicate of the active layer to the document. The new layer appears in the slot immediately to the right of the active layer. This is available only if there is at least one empty slot in the Layer palette.

<<: Moves the active layer up one slot, switching positions with the layer in the adjacent slot. Use this function to position layers next to one another in preparation for merging them.

>>: Moves the active layer down one slot, switching positions with the layer in the adjacent slot. Use this function to position layers next to one another in preparation for merging them.

Mrg: Merges the active layer with the one below it.

Below shows the top row of thumbnails before and after a merge operation.