v3ce − 3D curvature estimation

v3ce [if=<inputfile>] [of=<outputfile>] [-p] [-u] [-k1] [-k2] [-g] [-m] [-e] [-v] [-z]

V3ce performs curvature estimation on a 3D polygon file. Note that the polygon file must have been produced using a triangular tessellation (see v3pol -t). Absolute curvature (signed or unsigned) as well as the principle (k1 and k2), Gaussian, and mean curvatures may be estimated. The default operation is to estimate signed absolute curvature.

There are several outputs of the curvature analysis. The first is an augmented 3D polygon file where each 3D polygon object contains an additional generic float (VX_GFLOAT) with the curvature estimate for that triangle. These values can be extracted using other VisionX programs (see vgtovec(1) and vpr(1)). The output file itself can be viewed with v3d(1). To aid in this visualization, the -e flag expands the dynamic range of the colors assigned to the curvature estimates on the triangle surfaces. This expansion does not effect the true numeric values contained in each VX_GFLOAT element, and is only for purposes of visualization.

The -v (verbose) flag may be used to output runtime information to stderr, including minimum and maximum curvature estimates for the vertices and triangles in the object.

if=<output file>

specifies a VisionX 3D polygon (VX_V3D) input file, based on triangular tessellation.

of=<output file>

specifies a VisionX 3D polygon output file.

-p

inhibits packing of the output.

-u

specifies the estimation of unsigned curvature (removes distinction between convex (positive curvature) and concave (negative curvature) surfaces). The default is to produced signed curvature estimates.

-k1

estimate the k1 (maximum) principal curvature.

-k2

estimate the k1 (minimum) principal curvature.

-g

estimate the Gaussian curvature.

-m

estimate the mean curvature.

-e

perform dynamic range expansion on the colors assigned to the triangles in the output file, enhancing visualization. This does not effect numeric curvature estimates contained in each VX_GFLOAT value in the output.

-v

verbose operation. Gives some runtime information, including maximum and minimum curvature estimates for vertices and triangles.

-z

very verbose operation.

v3pol(1), v3pfilt(1), v3pclip(1), vsurf(1), vgtovec(1)

W. J. Kostis