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<big>Well, I tried using the offset, and the back-and-forth transform series.
But once it passed through the CleanPolyData filter, it STILL gave me the
band-o'-crap down the side. I'm starting to reach the same conclusion that
I had reached the last time I tried this -- namely, that merging the points
just isn't worth the headache. ;-)</big><br>
<br>
Sean McInerney wrote:<br>
<blockquote type="cite" cite="mid4124F2CF.1000003@nmr.mgh.harvard.edu">Jared,
<br>
<br>
You'll notice that the band of crap on your sphere is actually your entire
texture mirror mapped onto that single strip of polygons ... not just from
the center as I said previously ... unless that strip is 1 pixel wide ;-)
<br>
<br>
-Sean <br>
<br>
Sean McInerney wrote: <br>
<blockquote type="cite">Hi Jared, <br>
<br>
Actually, I think that I do understand your problem. If you merge the non-polar
points along the edges of the plane mapped to the sphere, what are the
texture coordinates of those points? Get it? Before the merge, they're zero
(0) on one side, one (1) on the other. After the merge, you are getting
an interpolation between 0 and 1 / thetaRes - 1 (i.e. some crap from the
center of your image being placed along that border). Furthermore, by using
the offsetting that I suggest, as well as going back and forth with the
transform, you'll avoid having a black hole at the north pole (you'll see
what I mean). The bottom line is that, for you, the only points worth merging
are probably the poles. Even then, you'll end up with texture artifact that
won't show up with merging. <br>
<br>
So, this doesn't solve the *grand* merging debate, but it may solve yours
;-) <br>
<br>
-Sean <br>
<br>
Jared Cohen wrote: <br>
<br>
<blockquote type="cite">Thanks, but I don't think you understand the
problem. I can close the gap just fine, but the two edges will overlap without
being merged together. It's when I merge them using a CleanPolyData filter
that I get the warping effect. <br>
<br>
<br>
<br>
<blockquote type="cite">Hi Jared, <br>
<br>
I have some C++ code based on the spherical Tcl example that I think solves
your problem. It avoids a singularity at the Z axis by offsetting the plane
by a very small amount. I am attaching the source file 'spherical.cxx'.
It takes any valid 2D vtkImageReader2 input and maps it to a sphere in the
manner that you describe. <br>
<br>
The Cmake configuration stuff is as follows: <br>
<br>
ADD_EXECUTABLE (spherical spherical.cxx) <br>
TARGET_LINK_LIBRARIES (spherical vtkRendering vtkIO vtkGraphics) <br>
<br>
-Sean <br>
<br>
</blockquote>
</blockquote>
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</blockquote>
</blockquote>
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