[vtkusers] Multiple iso-surfaces generated from labelled volume: smoothing & coloring

[Weiguang Guan]

Hi VTK users,

Maybe someone could help improve the rendering of multiple objects. I have 
a labelled volume (0: background; 1: bone, 2: muscle; ...), and want to 
display them with different colors. 

What I did is looping through the number of objects (or number of labels), 
in each loop i
	(1) threshold to get label i
	(2) vtkContourFilter
	(3) vtkWindowedSincPolyDataFilter
	(4) vtkPolyDataNormals
	(5) vtkPolyDataMapper
	(6) vtkActor
	(7) Set a specific color to the actor
The problem is that some objects penetrate (or overlap) others after 
deformation (vtkWindowedSincPolyDataFilter). I am afraid that I will have 
the same problem if I use vtkDiscreteMarchingCubes instead of multiple 
usage of vtkContourFilter.

Perhaps, a better way is to extract an "outmost" surface at iso-value = 
0.5 and omit the interfaces between objects. Then how to color different 
patches of the surface that correspond to different objects?

Thank you very much in advance.

Weiguang

-- 
========================================================
Weiguang Guan, Research Engineer
RHPCS, McMaster University
========================================================