This code performs gradient domain processing [SGP 2009] on signals defined on a mesh, where the signal can be either a color-field represented as a color per vertex or is the position of the vertices themselves. The code supports both sharpening and smoothing of the signals through the solution of a screened-Poisson equation. Specifically, given an input signal F, it solves for the signal G minimizing:

For more robust estimation of normals, the executable also supports harmonic smoothing of normals as described in [SIGGRAPH 2016]. As with the code above, this amounts to minimizing:

ShapeGradientDomain: Processes either the vertex positions, or per-vertex colors, performing isotropic/anisotropic gradient-domain smoothing and sharpening (with the option of smoothing normals in a pre-processing step)

--in <input geometry>

This string specifies the name of the input geometry, represented in PLY format.

[--out <ouput geometry>]

This string specifies the name of the output geometry, represented in PLY format.

[--vWeight <value interpolation weight>]

This floating point value gives the weight for value interpolation (α).
The default value for this parameter is 1.

[--gWeight <gradient interpolation weight>]

This floating point value gives the weight for gradient interpolation (β).
The default value for this parameter is 10^-4.

[--gScale <gradient scale>]

This floating point value gives the scale factor for the target gradient field (λ).
The default value for this parameter is 1.0.

[--kWeight <curvature weight>]

This floating point value gives the curvature weight for adjusting the metric (ε).
The default value for this parameter is 0.0.

[--nIters <normal smoothing iterations>]

This integer value gives the number of iterations of harmonic normal smoothing to be performed before estimating curvatures. (If normal smoothing is desired, we have found that a single iteration suffices.)
The default value for this parameter is 0.

[--nTime <normal diffusion time>]

This floating point value gives the normal diffusion time (γ).
The default value for this parameter is 10^-4.

[--useColors]

If this flag is enabled, the signal to be processed is the per-vertex color field. Otherwise, it is the vertex positions.
If the flag is enabled and the input file does not contain per-vertex colors, colors will be assigned from the normals.

[--verbose]

If this flag is enabled, the code will output processing information.

• Top row: Isotropic sharpening:

       ShapeGradientDomain --in armadillo.ply --out armadillo.sharp.ply --gScale 2 --gWeight <gradient weight> 

• Middle row: Isotropic smoothing:

       ShapeGradientDomain --in armadillo.ply --out armadillo.smooth.ply --gScale 0 --gWeight <gradient weight> 

• Bottom row: Anisotropic smoothing:

       ShapeGradientDomain --in armadillo.ply --out armadillo.smooth.ply --gScale 0 --gWeight <gradient weight> --kWeight 0.02 --nIters 1