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mrender - Man Page

a demonstration of hoover, gage, and nrrd measures


mrender [@file ...] [-i <nin>] -k <kind> -fr <eye pos> [-at <at pos>] [-up <up dir>] [-rh] [-or] -dn <near> -di <image> -df <far> [-ar] [-ur <uMin uMax>] [-vr <vMin vMax>] [-fv <field of view>] [-offfr] [-turn <angle>] [-is <image size>] [-iss <scale>] [-k00 <kernel>] [-k11 <kernel>] [-k22 <kernel>] [-rn] -q <query> -m <measure> [-gmc <min gradmag>] [-fn <from nan>] [-step [-nt <# threads>] [-vp <img coords>] [-o <filename>]


Uses hoover to cast rays through a volume (scalar, vector, or tensor), gage to measure one of various quantities along the rays, and a specified nrrd measure to reduce all the values along a ray down to one scalar, which is saved in the output (double) image.


@file ...

response file(s) containing command-line arguments

-i <nin>

input nrrd to render (nrrd); default: “”

-k <kind>

“kind” of volume (“scalar”, “vector”, or “tensor”) (gageKind)

-fr <eye pos>

camera eye point (3 doubles)

-at <at pos>

camera look-at point (3 doubles); default: “0 0 0

-up <up dir>

camera pseudo-up vector (3 doubles); default: “0 0 1


use a right-handed UVN frame (V points down)


orthogonal (not perspective) projection

-dn <near>

distance to near clipping plane (double)

-di <image>

distance to image plane (double)

-df <far>

distance to far clipping plane (double)


near, image, and far plane distances are relative to the at point, instead of the eye point

-ur <uMin uMax>

range in U direction of image plane (2 doubles); default: “nan nan

-vr <vMin vMax>

range in V direction of image plane (2 doubles); default: “nan nan

-fv <field of view>

angle (in degrees) vertically subtended by view window (double); default: “20


the given eye point (“-fr”) is to be interpreted as an offset from the at point.

-turn <angle>

angle (degrees) by which to rotate the from point around true up, for making stereo pairs. Positive means move towards positive U (the right) (double); default: “0.0

-is <image size>

image dimensions (2 ints); default: “256 256

-iss <scale>

scaling of image size (from “-is”) (float); default: “1.0

-k00 <kernel>

value reconstruction kernel (kernel specification); default: “tent

-k11 <kernel>

first derivative kernel (kernel specification); default: “cubicd:1,0

-k22 <kernel>

second derivative kernel (kernel specification); default: “cubicdd:1,0


renormalize kernel weights at each new sample location. “Accurate” kernels don’t need this; doing it always makes things go slower

-q <query>

the quantity (scalar, vector, or matrix) to learn by probing (string)

-m <measure>

how to collapse list of ray samples into one scalar. Possibilities include:


min”, “max”, “mean”, “median”, “mode”, “variance”, “skew”: (self-explanatory)


intc”, “slope”, “error”: intercept, slope, and error from line fitting


stdv”: standard deviation


cov”: coefficient of variation


product”, “sum”: product or sum of all values


L1”, “L2”, “NL2”, “RMS”, “Linf”: different norms


histo-min”, “histo-max”, “histo-mean”, “histo-median”, “histo-mode”, “histo-product”, “histo-l2”, “histo-sum”, “histo-variance”, “histo-sd”: same measures, but for situations where we’re given not the original values, but a histogram of them. (measure)

-gmc <min gradmag>

For curvature-based queries, set answer to zero when gradient magnitude is below this (double); default: “0.0

-fn <from nan>

When histo-based measures generate NaN answers, the value that should be substituted for NaN. (double); default: “nan

-step <size>

step size along ray in world space (double); default: “0.01

-nt <# threads>

number of threads hoover should use (int); default: “1

-vp <img coords>

pixel coordinates for which to turn on verbose debugging messages, or “-1 -1” to disable this. (2 ints); default: “-1 -1

-o <filename>

file to write output nrrd to (string); default: “-

See Also

gprobe(1), ilk(1), miter(1), nrrdSanity(1), overrgb(1), puller(1), tend(1), unu(1), vprobe(1)

Referenced By

gprobe(1), ilk(1), miter(1), nrrdSanity(1), overrgb(1), puller(1), tend(1), unu(1), vprobe(1).

April 2021