The Attract to Target Tool allows you to make one mesh conform to the shape of another. This has lots of uses. For one, it can be used to create forms that "fit" other things. You can also use it to transfer details from one model to another. You can even use it to manually "shrink-wrap" a shape. And finally you can use it to reconstruct sharp edges that may get lost in other operations.
To use this Attract to Target, you must first set a Target Object. See the Target Object section of the 3D Scene page for details on how to set a mesh as the active target. The image below shows a basic example usage of the tool. The sphere mesh is set as target (hence the semi-transparent blue rendering), and Attract to Target is applied to the selected area of the bunny head. The result is that this selected area is pulled onto the surface of the sphere, as shown in the rightmost image.
The property panel for Attract to Target is shown to the right. The Accuracy and Regularity sliders are similar to in other tools - they control the density and smoothing of the remeshing done by this tool. See the Remesh Tool for details. This remeshing can be disabled with the Enable Remeshing checkbox (example below).
Offset allows you to attract to an outset or inset shell (see below).
The Preserve Groups option, when enabled, constrains any facegroup boundaries contained in the selection. This can sometimes cause artifacts in the result, like in other remeshing-based tools.
The Preserve Boundaries checkbox, when enabled, pins mesh boundary vertices to their initial positions. Otherwise they will also be pulled onto the target.
Finally the Find Sharp Edges option, when enabled, causes Attract to Target to try to recover creases in the underlying target surface. See below for more.
Remeshing and Offset
The images below show a default Attract (left), the result with Enable Remeshing un-checked (center), and the result with a negative Offset value (right). In the no-remeshing example, note that the triangle connectivity is precisely preserved. This makes Attract to Target a useful tool if you wish to deform a fixed mesh to fit different shapes.
Find Sharp Edges
The Find Sharp Edges option is particularly useful in the workflow we show below. We have two meshes, a sphere and a cube, which are overlapping (top-left). The Make Solid Tool can be used to merge them into a single shape, but the sharp edges will be lost (top-right). However, if we use the original objects as the Target (they may need to be combined), and select the areas where there were sharp edges (bottom-left), then the Find Sharp Edges option will usually recover those sharp edges (bottom-right).
Note that in the bottom-left image we have un-checked Transparent Target in the View menu, otherwise the selection is quite obscured (the weird colors are rendering artifacts from the original and solid surfaces being overlapping). Also, it is possible to do this with the entire object (ie Select-All), however the Attract to Target operation may take quite a while.
If you use this workflow and notice some glitches, try doing additional Attract to Target operations locally, and changing the Accuracy and Regularity settings. This usually resolves local artifacts. However, the way that Find Sharp Edges works is by trying to align each triangles face-normal with the underlying surface normal. So, if your Attract surface is much higher resolution than your Target surface, it is likely to pick up any local deviations.
Detail Transfer Example
This section continues from the face-transfer example on the Align to Target page. The idea is that we have a new face (from a 3D scan) that we would like to insert into the underlying mesh. We have already positioned it appropriately, and set this face as the Target object. Now we can brush the areas we wish to modify on the base surface and use Attract to Target to transfer the details of the scan to those areas. In this example, I wanted to keep the handlebars, so I painted around the moustache. Note that the top of the head scan is not closed. Because the head mesh we are attracting is closed, it essentially "shrink-wraps" this open hole. Perhaps this gives you a sense of how to use Attract to Target to do manual shrink-wrapping and mesh repair.