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Shrinkwrap Modifier

Description

The Shrinkwrap modifier allows an object to “shrink” to the surface of another object. It moves each vertex of the object being modified to the closest position on the surface of the given mesh (using one of the three methods available). It can be applied to meshes, lattices, curves, surfaces and texts.

As for most of the deform modifiers, the affected “vertices” are the “computed” one, i.e. the real geometry of the object at the time the modifier is calculated, and not the original vertices/control points.

In some way, Shrinkwrap acts like a view-independent retopo tool, since the vertices are projected along their normal or moved to the nearest surface point. But it doesn’t give accuracy problems as retopo, since it works in object space instead of image space. Also it’s possible to “keep a distance” from the target position.

Options

The default Shrinkwrap modifier panel.

Ob

Shrink target, the mesh to shrink/wrap around.

VGroup

The weight paint for this vertex group of the current modified mesh will controls whether and how much each vertex is displaced to its target position. If a vertex is not a member of this group, it is not displaced (same as weight 0)

Offset

The distance that must be kept from the calculated target position, in Blender Units.

SS Levels

This should apply a (temporary) Catmull-Clark subsurf to the modified object (or it’s target?), before computing the wrap… But it does not seem to have any effect…

Shrinkwrap type

This drop-down list specifies the method to be used to determine the nearest point on the target’s surface for each vertex of the modified object. Some options will add some extra, specific controls to the panel.

The Shrinkwrap modifier with nearest surface point method.

nearest surface point

This will select the nearest point over the surface of the shrink target. It adds one extra option

Above surface

When enabled, the shrunk vertices are always kept above (on the front side) of their “floor face” (i.e. the face they are the nearest from). This is only meaningful when Offset is not null.

The Shrinkwrap modifier with projection method.

projection

This will project vertices in a given direction, until they touch the shrink target. The vertices never touching the shrink target are left in their original position. This implies that, depending on the settings of this option (especially when using the Normal projection axis) and the relative positions of the two objects, the modified object might sometimes remain undeformed… This is not a bug, just “play” with the settings (especially the Negative/Positive ones), or move one of the objects around…

This method is the hardest to master, as it might sometimes gives unexpected results… It adds quite a few extra options:

Normal, X, Y, Z

Along which direction the projection is done. Normal will use the modified object’s normals as project “axis”, and is mutually exclusive with the other three options. X, Y and Z will use the corresponding local axis of the modified object – they can be combined with each other, yielding a “median axis” of projection.

Negative and Positive

This allows you to select the allowed direction(s) of the shrink along the selected axis.

Cull frontfaces, Cull backfaces

This allows you to prevent any projection over the “front side” (respectively the “back side”) of the target’s faces. The “side” of a face is determined by its normal (front being the side “from where” the normal “originates”).

0b2

An additional object to project over…

The Shrinkwrap modifier with nearest vertex method.

nearest vertex

This will select the nearest vertex of the shrink target. It adds no extra option.

Examples

Artists have found many uses for this modifier. Here are some of those showing Shrinkwrap modifier utility.

Shrinkwrapping a skirt to a model: simply paint the vertices that are supposed to be close to the target’s mesh.

Basic example of shirt making: just make a very simple cage and shrinkwrap it to the model.

Shrinkwrapping a curve to a terrain: apply a projection along the Z axis.

Using shrinkwrap to achieve skin slide (Renderdemon idea).