[Radiance-general] Re: Radiance-general Digest, Vol 37, Issue 7

[Jelle Feringa / EZCT Architecture & Design Research]

Hi Martin,

I agree with Francesco, (t)vtk is a good option, there is a powerful surface
reconstruction method.
https://svn.enthought.com/enthought/wiki/*TVTK*
Something else you might want to look into is cgal's alpha-shapes.
If you allow me for yet-another-python-plug:
http://cgal-python.gforge.inria.fr/
implements this functionality:
http://www.cgal.org/Manual/3.2/doc_html/cgal_manual/Alpha_shapes_3/Chapter_main.html

Here's a tvtk snippet that might of some use:

---------------------------------------------------------------------------------------------

import random
from pickle import loads
from pprint import pprint
from enthought.pyface import GUI

import numpy as np
import scipy as sp

from enthought.tvtk.tools import ivtk
from enthought.tvtk.api import tvtk
from enthought.pyface.tvtk import actors

gui = GUI()
window = ivtk.IVTKWithCrustAndBrowser(size=(800,600))  # Size is optional.
window.open()

# note that this data is generated with ALL rtrace output flags enabled!
f =
open('E:\\EZCT\\EZCT___projects\\Seroussi_House\\01_Correspondance\\send_program_to_marc\\rtrace_values.pickle')
rtrace_values = loads(f.read())

radiance_origin     = rtrace_values[:,:3]
radiance_direction  = rtrace_values[:,3:6]
radiance_value      = rtrace_values[:,6:9]
radiance_value      = ((radiance_value * sp.array((0.265, 0.670,
0.065),'f'))*110.)/3683.
# -> Lux conversion
radiance_vec_length = rtrace_values[:,9:10]


radPts  = tvtk.Points(data=radiance_origin)
radPoly = tvtk.PolyData(points=radPts)
radPoly.point_data.vectors = radiance_direction
radPoly.point_data.scalars = radiance_value

reducedRadPts = tvtk.MaskPoints(input=radPoly, on_ratio=10)
reducedRadPts.output.point_data.vectors = radiance_direction
reducedRadPts.output.point_data.scalars = radiance_value



thresh  = tvtk.ThresholdPoints(input=radPoly)
thresh.threshold_between(radiance_value.mean(), radiance_value.max())

ugrid = tvtk.UnstructuredGrid(points=radPts)



#srf         = tvtk.ContourFilter(input=thresh.output)


srf     = tvtk.SurfaceReconstructionFilter(input=thresh.output)


cf = tvtk.ContourFilter(input=srf.output)
cf.set_value(0, 0.0)

srfMap  = tvtk.PolyDataMapper(input=cf.output)
srfProp = tvtk.Property(representation='s')
srfActor= tvtk.Actor(mapper=srfMap, property=srfProp)
window.scene.add_actor(srfActor)

---------------------------------------------------------------------------------------------

from here use window.scene.(save_obj?) to export the reconstructed surface
to a polygon file.

By the way, are you still working on top-down-lighting design approaches
Martin?
Very inspiring research!

-jelle
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