# Create isosurface

Two isosurfaces of the charge density field

This modifier generates an isosurface for a field quantity defined on a structured voxel grid. The computed isosurface is a surface mesh data object and its visual appearance is controlled by the accompanying surface mesh visual element.

To create multiple isosurfaces at different iso-levels, insert several instances of the the modifier into the same pipeline.

See the list of supported input file formats to find out which ways of importing voxel grid data into the program are available. OVITO Pro also offers the Spatial binning modifier, which lets you dynamically generate a grid by binning a system of particles.

Transfer field values

The option Transfer field values to surface copies all field quantities defined on the input voxel grid over to the isosurface’s mesh vertices. This includes any secondary field quantities in addition to the selected primary field quantity for which the isosurface is being constructed (which is constant and equal to the iso-level across the entire surface). The color mapping mode of the Surface mesh visual element lets you locally color the isosurface based on some secondary field quantity. The local field values at each isosurface output vertex are computed from the data of the input voxel cells using trilinear interpolation.

Surface smoothing

The resulting isosurface can optionally be smoothed using a fairing algorithm to even out surface steps resulting from the discrete nature of the voxel grid. The Smoothing level parameter controls the number of iterations of the smoothing algorithm to perform. This post-processing procedure slightly displaces the surface mesh vertices to reduce steps and roughness of the isosurface. Mesh smoothing is performed after interpolated field values have already been transferred to the surface. Therefore, the surface values reflect the original vertex positions before the smoothing procedure.

See also

`ovito.modifiers.CreateIsosurfaceModifier` (Python API)