244 chapter 7 ■ Transpose, ZSphere Rigging, Retopology, and Mesh Extraction
- With the low-res mesh selected, subdivide as high as the original ZTool. For example,
if the original sculpt was 1 million faces, you want to divide the low-res cage at least
as high. Once this mesh is subdivided, click the ProjectAll button under the SubTool
menu (Figure 7.41). This will project the currently active subtool onto the other, inac-
tive tools.
The ProjectAll button has four sliders and three button controls. The Dist slider controls
the distance the imported mesh will project to tr y to wrap to the original mesh. Adjust
this slider if some points are missed in the projection because they seem too far away from
the original Z Tool sur face. You can reduce this slider value if you find fingers and toes pro-
jecting into each other because they are so close together. The Mean slider averages the
point difference between the source and target meshes. The PA Blur slider will help avoid
spikes in areas of tight projection like the space between the fingers or toes. It does this by
adjusting the projection algorithm based on the number input in the slider. It will apply a
smoothing to the mesh before the projection. A value of 100 will add a maximum blur
to the projection. The remaining slider is called Projection Shell. Projection Shell allows
you to virtually offset the mesh so that it is inside or outside the original Z Tool. This helps
ensure that the points of your projection mesh have a clear direction to project to best
capture the mesh details. By activating the Farthest, Inner, or Outer button, you can spec-
ify the projection direction. In step 3, we will look at Projection Shell in depth.- With two meshes in the same world space as we have here, it is an ideal way to transfer
detail to other meshes without the complexity of Topology tools. Click the ProjectAll
button and your mesh will capture the original ZTool detail. Figure 7.42 shows the
new mesh. The original ZTool has been hidden for clarity.
ZBrush 4 introduced a new tool for assisting in getting the best possible pro-
jection between two meshes. This tool, called Projection Shell, is a slider under the
SubTool menu. Adjusting the slider will add an overall inflate or deflate to the mesh
you want to project onto the high-res mesh. The benefit is that it ensures every point
of the projection mesh lies inside or outside the target surface. Figure 7.43 shows a
projection shell (colored red for clarity). Raising the
Projection Shell slider will inflate the shell outside
the surface of the target mesh. Consider this a way
of visualizing the projection. With the projection
shell outside the target mesh (so no gray is showing
from the original sculpture), make sure Inner is acti-
vated. With this option enabled, ZBrush projects
only to those points on the sculpture that lie inside
the projection shell. - In some cases, errors will occur. Errors are espe-
cially prone to happen when the low-res mesh does
not match the high-res closely enough. They are
simple to fix using the ZProject brush. From the
Brush menu select the ZProject brush (Figure 7.44).
Make sure ZAdd is on and both subtools are vis-
ible. Create the projected mesh with the error active.
Figure 7.41 The
ProjectAll button
is located in the
SubTool menu.
Figure 7.42 Projected topology