Non-rigidly fits one geometry to another. For example wraps a generic basemesh around a specific 3D-scan. Lets you control fitting process by providing user-defined point correspondences. Also allows excluding certain polygons from fitting process.
Wrapping is a very efficient approach when dealing with big set of similar objects like human scans so that all of them can be described with the same topology.
The basemesh topology should be manifold.
All the polygons should be interconnected, no disconnected pieces like eyeballs, teeth are allowed.
If the basemesh contains multiple disconnected pieces, you have several options.
If vertex order should be preserved, you can wrap a model without those disconnected pieces and then apply this deformation to original model using Lattice node.
The basemesh should be roughly pre-aligned to a target geometry.
If the models are not aligned you can use RigidAlignment node to align them by translation, orientation and scale.
If a head basemesh contains eye- or mouth-socket, select corresponding polygons and pass them as fourth input of wrapping node. That will exclude them from fitting process.
Wrapping Under the Hood¶
Wrapping uses coarse-to-fine approach. The basemesh is deformed by a set of control nodes (displayed as white dots during wrapping process). The process is divided into several steps. Each step a set of control nodes is generated on the basemesh with specific density which increases with each new step. The algorithm tries to find such position of control nodes so that the basemesh fits the target geometry as close as possible. When a solution is found, it proceeds to the next step. It samples the basemesh with bigger number of control nodes and repeat the fitting again. The bigger the number of control nodes in current step the more precise the result.
Wrapping node has an editor which displays floating geometry, fixed geometry, points and free polygons as you plug the inputs.
- floating geometry
GeometryGeometry to be deformed (a basemesh)
- fixed geometry
GeometryTarget geometry to fit to
- point correspondences
PointCorrespondences(optional) A set of point correspondences between the floating and the fixed geometry
- free polygons floating
PolygonSelection(optional) A set of polygons that will be excluded from wrapping process, i.e they will not try to fit the fixed geometry but will be deformed as rigid as possible to match the rest of the polygons.
if set, the node will be recomputed each time some parameter or input data is changed
if auto-compute is off, starts wrapping process in preview window
number of fitting steps
- ICP iterations
number of alignment sub-steps inside each fitting step
- optimization iterations
maximal number of optimization sub-steps inside each fitting step
- sampling initial
density of control nodes during the first fitting step
- sampling final
density of control nodes during the last fitting step
Advanced parameters tab¶
- smoothness initial
mesh rigidness during the first fitting step
- smoothness final
mesh rigidness during the last fitting step
- control points weight
how much force is applied to stitch user-defined corresponding points to each other
- max optimization iterations
maximal number of optimization interations
- normals threshold
don’t try to fit floating and fixed vertices if the angle between their normals is bigger than a specific value in radians
- Dp initial
optimization delta during the first fitting step
- Dp final
optimization delta during the last fitting step
For accurate wrapping of clean scans with minimal noise
Decrease sampling final and smoothness final parameters
Increase ICP iterations and optimization iterations
For robust wrapping of noisy scans with a lot of artifacts
Increase sampling final and smoothness final parameters