Wrap Mode Tutorial
From ZBrush Info
Contents |
Overview
Wrap Mode allows the artist to create tileable geometry. As the artist sculpts off the edge of the left side of a plane, the stroke will continue on to the right side.
This feature allows artists to quickly and easily create tileable normal maps and bump maps for texturing and in-game use.
How It Works
Let's take a look at how to use ZBrush 3 features to sculpt a tileable plane of bricks. This will be a true 3D sculpture. Once completed, displacement, bump, or normal maps can be generated for tiling in other applications.
Lay Down a Brick Pattern
We want to start with a basic brick pattern first--an array of approximately rectangular displacements on the surface of the plane. With ZBrush 3, this is easy.
1. Set Brush:WrapMode to 4. A value of 1 or more means that strokes will wrap from side to side, or top to bottom, making a tileable texture. Values of more than 1 also repeat strokes automatically across the surface of the plane, allowing just a few strokes to lay out an entire grid of bricks.
(Note: Set your brush stroke to "Dots".)
2. The first iteration of brick geometry should produce bricks of uniform height. To do this, first press Tool:Morph Target:StoreMT...
3. ...and then select the Layer sculpt brush. With a morph target stored, Layer will sculpt above (or below) the surface of the morph target, not the current surface. This is great for creating smooth, uniform-level surfaces.
4. Put some bricks on the surface. The geometry below was created with two brush strokes.
In ZBrush 3, WrapMode works well with most of the the available stroke types (Dots, Spray, etc.), but does not appear to work correctly with the Freehand stroke.
In this image, the setting of WrapMode to 4 caused the repetition of strokes to fill in the entire surface.
Establish Irregularities
With the initial grid of bricks laid down, it's time to add some irregularities to make the wall more realistic.
1. Press Tool:Morph Target:Del MT, and then Tool:Morph Target:Store MT. The morph target now includes the basic brick geometry, and so using the Layer brush again, we can stroke out an additional layer of geometry on top of the bricks.
2. Next, set Transform:WrapMode to 1. At a setting of 1, strokes will wrap top to bottom and left to right, but will not repeat within the plane. This is ideal for breaking up the repetitiveness of our sculpt, while still maintaining tileability. In this case, we'll sculpt the grooves between the bricks. This will break up what was previously a flat plane, and also change the shapes of the bricks.
3. After some more of this, we end up with a nice base brick wall, with no internal repetition.
Add Details
The wall is looking pretty good at a coarse level, but shows none of the real-world pitting and granularity of real brick and mortar surfaces. Of course, this is where ZBrush excels! A plane of just (!) a million polygons or so will allow us to sculpt all of this detail in.
To do this, we'll use (and show off) a feature of ZBrush 3: Layers. Layers will allow us to not only sculpt in the details in the normal manner, but then to adjust the magnitude of the layer sculpting afterwards.
1. Press Tool:Layer:Create. This creates and turns on a new layer in which our detailing will take place. The detailing will show up in the on-screen sculpt, but the original surface will be unchanged--the sculpting is (in effect) stored as a difference between the original sculpt, and what we do in the detailing.2. Now select Stroke:Spray and Alpha:Alpha23 (a sort of random dots pattern) for the sculpting. This will give us a nice non-repetitive irregular surface sculpt.
3. First, paint over the surface with the plane scaled fairly small. The scale of the alpha and stroke is relative to the screen, not to the model, so this will produce relatively 'coarse' effects on the brick and mortar surfaces.
4. Next, zoom in on the plane, and paint over it with the same settings. If necessary, you can look at only a portion of the plane at a time, moving it with Alt-Drag. Since the same size of brush and alpha is applied over smaller portions of the wall, the effect is to create graininess rather than the coarser irregularity above. Let's take a quick look at the wall as it stands:
Afterwards
That's all there is to sculpting a tileable brick surface. You can now use ZBrush's other built-in features to create displacement, bump, or normal maps. All of these will also be tileable, and can easily be used in other 3D applications.
