## Module: Fit Molecule To Map (
)

### Description:

> This is an experimental module from the Xtra Library: https://xtras.amira-avizo.com. Using this module a molecular model (e.g., as imported from PDB) can be "docked" into a density map, i.e., a scalar field. Internally, the molecular model is converted to an electron density map using Pseudo Electron Density and then rigidly registered using Register Images. Quality and/or success of the alignment are highly dependent on the proper pre-alignment. For that, the module provides two automatic pre-alignment methods, namely aligning the centers or the principal axes. This pre-alignment can be further improved using the Transform Editor. Press Apply to start fitting.

### Connections:

> Molecule `[required]`
> Connect an object of type HxMolecule to this port. This data will be the model of the registration.

> Map `[required]`
> Connect a uniform scalarfield to this port. This data will be the reference of the registration.

About
This port prints the version of the module.

Info
When fitting has finished, this port prints the transformation matrix of the model.

Prealign
This port provides two methods for prealignment.
Align Centers: Pushing this button aligns molecule and map according to their density weighted center of gravity.
Align Principal Axes: Pushing this button aligns molecule and map according to their density weighted principal axes.