<div dir="ltr"><div>Howdy.</div><div><br></div>On Tue, Jul 15, 2014 at 8:35 PM, Greg Schussman <span dir="ltr"><<a href="mailto:greg.schussman@gmail.com" target="_blank">greg.schussman@gmail.com</a>></span> wrote:<br>
<div class="gmail_extra"><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><div dir="ltr">
<div><div><div><div>Hi.<br></div></div></div></div></div></blockquote><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
<div dir="ltr"><div><div><div><div>I'm not sure how things are meant to connect. I'm working in python. I'm trying to build and use a reader. Many examples seem to assume there's only a single field that can be made active. But in my case, the reader is where I keep all information, and there is no sense (at least in my mind) of an "active" field, because several may be used at ones (scalar for surface coloring, one vector field for one set of cone glyphs, and another vector field for a different set of cone glyphs, all to be displayed at the same time).<br>
</div>
<br></div></div></div></div></blockquote><div><br></div><div>The "Active" concept in VTK is mostly an artifact of days of yore. The modern way to tell a filter what array to operate on is with vtkAlgorithm::SetInputArrayToProcess (<a href="http://www.vtk.org/doc/nightly/html/classvtkAlgorithm.html#a42a55ca2c277aecc909ad592d12978aa">http://www.vtk.org/doc/nightly/html/classvtkAlgorithm.html#a42a55ca2c277aecc909ad592d12978aa</a>). Most but not all filters respect that.</div>
<div><br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><div dir="ltr"><div><div><div></div><div>I create the each field this way (where my_voltages is just a python list that I parsed from a file):<br>
<br></div><div> voltage = vtkDoubleArray()<br></div><div> voltage.SetName('voltage')<br></div>
<div> voltage.SetNumberOfComponents(1)<br></div><div> for v in my_voltages:<br></div><div> voltage.InsertNextValue(v)<br><br></div><div>And I did the same thing for the 3D fields, except using 3 for the number of components.<br>
</div><div></div>Then, I add these fields to my reader (derived from vtkProgrammableSource) this way:<br><br></div><div> # 1D fields:<br></div> self.GetPolyDataOutput().GetCellData().AddArray(voltage)<br> self.GetPolyDataOutput().GetCellData().AddArray(charge)<br>
<br></div> # 3D fields:<br><div> self.GetPolyDataOutput().GetCellData().AddArray(current_density_real)<br> self.GetPolyDataOutput().GetCellData().AddArray(current_density_imag)<br><br></div><div>I'm able to iterate through those and print out the correct values and some of my early scalar visualization with colormaps and such seem to be working.<br>
<br></div><div>So, first question is: does what I have done so far seem reasonable or is there a more vtk-ish way of doing this?<br><br></div></div></blockquote><div><br></div><div>You are doing it just right.</div><div>
</div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><div dir="ltr"><div></div><div>Second question is how to connect to the reader. I'm trying to use it this way:<br>
<br></div><div> cone = vtkConeSource()<br> cone.SetRadius(0.1)<br> cone.SetHeight(0.5)<br> cone.SetResolution(8)<br><br> glyph = vtkGlyph3D()<br> glyph.SetInputConnection( WHAT GOES HERE??? )<br><br></div>
</div></blockquote><div> </div><div>reader.GetOutputPort()</div><div><br></div><div><br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
<div dir="ltr"><div> glyph.SetSourceConnection(self.cone.GetOutputPort())<br>
glyph.SetScaleModeToDataScalingOff() <br> glyph.SetScaleFactor(1.0e-3)<br> glyph.SetVectorModeToUseVector()<br> glyph.OrientOn()<br><br></div><div>So the "what goes here" is this question. Because I used a named array, I'd hope for something like:<br>
<br></div><div> glyph.SetInputConnection(reader.GetOutputPort('current_density_real'))<br><br></div><div>But that doesn't work, and I've seen nothing to suggest that it would. When I try this as the argument,<br>
</div><div> <br> reader.GetPolyDataOutput().GetCellData().GetArray('current_density_real')<br><br></div></div></blockquote><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
<div dir="ltr"><div></div><div>Is this a matter of converting an array to an algorithm output? It seems (probably quite wrongly) to me that algorithms can produce many different kinds of output, and that a vtkArray would reasonably be one of them. </div>
</div></blockquote><div><br></div><div>Close but no cigar. Algorithms produce vtkDataObjects, which contain any number of vtkArrays. Use SetArrayToProcess to tell the filter which of the arrays you want it to process.</div>
<div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><div dir="ltr"><div> Or, when using the SetInput(), why wouldn't a vtkArray be a vtkDataObject? Of course, the easy answer is "that's not how the inheritance diagrams are drawn", but that doesn't really get me closer to groking the intended grand scheme of things. I'm not complaining; I'm just confused.<br>
</div></div></blockquote><div><br></div><div>You are not the first.</div><div> <br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
<div dir="ltr"><div></div><div>How to I get the glyph to use the vector data (in the vtkArray) as its input? (or if that's the wrong way to think about this, then what's the right way?)<br></div><div><br></div></div>
</blockquote><div><br></div><div>glyph.SetInputArrayToProcess(0,0,0,"vtkDataObject::FIELD_ASSOCIATION_CELLS", "thickness0")<br></div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
<div dir="ltr"><div>Many thanks in advance for any help/enlightenment.<span class=""><font color="#888888"><br>
<br></font></span></div><span class=""><font color="#888888"><div>Greg<br></div><div><br></div></font></span></div></blockquote></div></div><div class="gmail_extra"><br clear="all"><div>David E DeMarle<br>Kitware, Inc.<br>
R&D Engineer<br>21 Corporate Drive<br>Clifton Park, NY 12065-8662<br>Phone: 518-881-4909</div><div><br></div></div></div>