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Suzanne,<BR>
<BR>
If you've got to the stage of importing the G3D (volume) file into NVIZ, and if it has the variable (w) attribute running through the volume, isosurfaces can be created by:<BR>
<BR>
<UL>
<LI>Selecting 'Isosurfaces' from the 'Visualization type';</LI>
<LI>Clicking 'Add' from the right-hand menu;</LI>
<LI>Where it prompts you for a digit, enter a value of the variable which is contained within the volume. For example, when I wanted to highlight areas within Loch Lomond which had 0.15mM of dissolved carbon, I entered 15 at this stage (I had multipled all values by 100 at an earlier stage). As long as this number was contained within the original data converted into the G3D file (e.g. if a text file contains 4 columns of x, y, z and the variable attribute, this attribute must be selected when the G3D file is created - from what you said about getting the slices to work, it sounds like this has already been done), the interpolated boundary lines for 0.15mM throughout the lake were then visualized with isosurfaces. In the screen grab below, I performed this for 0.15mM and 0.20mM.</LI></UL>
<BR>
<U><FONT color=#0000ff><A href="http://img222.imageshack.us/img222/8780/isosurfacesinnviz.jpg">http://img222.imageshack.us/img222/8780/isosurfacesinnviz.jpg</A></FONT></U><A href="http://yfrog.com/66isosurfacesinnvizj"></A><BR>
<BR>
It's been a few months since I used GRASS, so if those instructions don't work I can go back and figure out precisely how it was done.<BR>
<BR>
Craig Wilson<BR> </body>
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