You could:<br><br>1) As you stated, compute the isosurface of the first function.<br>2) Probe the second function with the first function polydata using vtkProbeFilter.<br>3) Run contour filter on the output of 2).<br><br>
<div class="gmail_quote">On Sun, May 1, 2011 at 2:56 PM, Luke <span dir="ltr"><<a href="mailto:hazelnusse@gmail.com">hazelnusse@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
I have the following two real valued functions:<br>
f1(x,y,z) = 0<br>
f2(w,x,y,z) = 0<br>
<br>
And I would like to compute their intersection surface in the x,y,z<br>
space. In the x, y, z space, the intersection surface will be some<br>
sort of 2d surface parameterized by w.<br>
<br>
The first function is a fairly simple one and I have already used<br>
vtkImplicitFunction to plot the iso-surface of that function alone.<br>
The second function is computationally more expensive to evaluate.<br>
<br>
The next step I would like to do is to treat w as a parameter, and<br>
compute the intersection of f2_w with the surface defined by f1=0.<br>
This should result in a curve in the x,y,z space. I can imagine doing<br>
this for a large number of values of w, so that I get a bunch of<br>
curves in the x,y,z space, each defining the intersection of the two<br>
surfaces.<br>
<br>
It seems like the efficient way to do this is to compute the polydata<br>
for the first function's iso-surface (using vtkMarchingCubes), and<br>
then for every cell in that surface, compute the intersection with the<br>
function f2, for all the values of w that I decide upon. This would<br>
allow for the polydata of the first surface to only be traversed only<br>
once. What I'm not clear on is how to implement this second<br>
intersection testing for each cell of the first surface and for each<br>
different value of w.<br>
<br>
Finally, once I have all the the intersection curves for each value of<br>
w, is there a way to plot these as a surface, rather than a bunch of<br>
lines? This would give me what I am ultimately after, namely the 2d<br>
intersection surface in the x, y, z, space.<br>
<br>
Thanks,<br>
~Luke<br>
<br>
--<br>
"Those who would give up essential liberty to purchase a little<br>
temporary safety deserve neither liberty nor safety."<br>
<br>
-- Benjamin Franklin, Historical Review of Pennsylvania, 1759<br>
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</blockquote></div><br>