<div dir="ltr">James,<div>You are missing image->SetDimensions() - that may be a reason why your scalar does not have all values.</div><div><br></div><div>vtkRectilinear grid is like an image data with variable extents and warped grid.</div><div><br></div></div><div class="gmail_extra"><br><div class="gmail_quote">On Fri, Aug 21, 2015 at 6:55 AM, James Furness <span dir="ltr"><<a href="mailto:pcxjf1@nottingham.ac.uk" target="_blank">pcxjf1@nottingham.ac.uk</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Hello,<br>
<br>
I have a program that will produce an output either in csv, or a binary format (which I have written and can alter).<br>
<br>
The data points are constructed by taking 3 vectors, and stepping at set intervals along these vectors to construct a 3D set of data. Ultimately there shouldn’t be a restriction on the three vectors, so the data may not be in a rectilinear array. But I’m leaving this for now and assuming the data is constructed from 3 orthogonal Axis aligned vectors to create a rectilinear structured grid. When I have a better grasp of preview readers I’ll update the reader to account for this. I guess it would require an unstructured data type to handle non-orthogonal grids?<br>
<br>
Also, the user is free to select what data they save from the program. This could be many fields, both vector and scalar quantities. What has been selected is stored in a header to the file, and known on reading. For my toy example I save only one scalar quantity.<br>
<br>
I’ve been trying to write a reader for paraview to import the binary files output. The csv format works ok, but the files can become large and it is a pain to have to construct the vector quantities from 3 scalars in each case, I want to avoid the user having to do this work. Another reason for writing a custom reader is to include additional information into the binary file for visualisation (e.g. the position of atoms, not a field quantity).<br>
<br>
With that background and reasoning I have managed to follow the documentation enough to read a basic test file, get the origin and point spacing, and read a single scalar quantity into a vtkDataArray owned by a vtkImageData object. Paraview picks this up seemingly correctly, with one flaw:<br>
<br>
It only takes 2 elements from each dimension, 0 and 1 displaying 8 elements in total. I am confident it has read the other values correctly as the Information tab reports “X extent 0 to 3” “X range: -1 to 1” (as expected) and similar for the other dimensions. If I view the data in spreadsheet layout the 8 values it has seem correct, but the others are missing.<br>
<br>
The code I am using in the reader’s RequestData( ) function is added below.<br>
<br>
Does anyone know why this may be happening and how to fix it? Also, any advice on how I should structure the reader to handle the non-orthogonal data?<br>
<br>
Thanks for your time, and thank you for such a stellar program. The results paraview produces for this data is brilliant, hence my want to make it convenient for our users!<br>
<br>
Regards,<br>
James Furness<br>
<br>
<br>
CODE for RequestData( ) Method:<br>
———————————————————————<br>
<br>
int LondonReader::RequestData(<br>
vtkInformation*,<br>
vtkInformationVector**,<br>
vtkInformationVector *outputVector)<br>
{<br>
vtkWarningMacro("Requesting the data!");<br>
<br>
<br>
ifstream finp;<br>
finp.open(this->FileName, ios::in | ios::binary);<br>
<br>
if (finp.is_open()) {<br>
cerr << "File is open without problem!" << endl;<br>
} else {<br>
cerr << "File failed to open :(" << endl;<br>
return 0;<br>
}<br>
<br>
// size of real numbers may not be 8. Check for this from file header<br>
int realSize;<br>
finp.read((char*)&realSize, sizeof(int));<br>
if(realSize != 8) {<br>
cerr << "Not implimented yet!" << endl;<br>
return 0;<br>
}<br>
<br>
// number of data fields<br>
int nFields;<br>
finp.read((char*)&nFields, sizeof(int));<br>
<br>
vtkImageData* image = vtkImageData::GetData(outputVector);<br>
<br>
// Read the dimensions of the grid and set the extent accordingly<br>
int gridDim[3];<br>
finp.read((char*)&gridDim, 3*sizeof(int));<br>
int extent[6] = {0, gridDim[0]-1, 0, gridDim[1]-1, 0, gridDim[2]-1};<br>
image->SetExtent(extent);<br>
<br>
<br>
// Read the field names from the file<br>
std::vector<std::string> fields;<br>
std::string strBuf;<br>
for (int i = 0; i < nFields; i++) {<br>
std::getline( finp, strBuf, '\0');<br>
fields.push_back(strBuf);<br>
cerr << "Printing Fields (" << i << "): " << fields[i] << endl;<br>
}<br>
<br>
// setup image for only one field for test case<br>
image->AllocateScalars(VTK_FLOAT, 1);<br>
vtkDataArray* scalars = image->GetPointData()->GetScalars();<br>
<br>
// currently there is only one field 'rho'<br>
scalars->SetName(fields[3].c_str());<br>
<br>
double x, y, z, rho;<br>
double oX, oY, oZ; //origin coordinates<br>
double sX, sY, sZ; //spacing of points<br>
<br>
for (vtkIdType itx = 0; itx < gridDim[0]; itx++) {<br>
for (vtkIdType ity = 0; ity < gridDim[1]; ity++) {<br>
for (vtkIdType itz = 0; itz < gridDim[2]; itz++) {<br>
finp.read((char*)&x, realSize);<br>
finp.read((char*)&y, realSize);<br>
finp.read((char*)&z, realSize);<br>
finp.read((char*)&rho, realSize);<br>
<br>
// Find and set the origin and spacing<br>
if (itx == 0 && ity == 0 && itz == 0) {<br>
image->SetOrigin(x, y, z);<br>
oX = x; oY = y; oZ = z;<br>
} else if (itx == 1 && ity == 0 && itz == 0) {<br>
sX = x - oX;<br>
} else if (itx == 0 && ity == 1 && itz == 0) {<br>
sY = y - oY;<br>
} else if (itx == 0 && ity == 0 && itz == 1) {<br>
sZ = z - oZ;<br>
}<br>
//check correct read.<br>
cerr << x << "," << y << "," << z << "," << rho << ", at " << itx*(gridDim[1]*gridDim[2]) + ity*gridDim[2] + itz << endl;<br>
<br>
//add value<br>
scalars->SetTuple1(itx*gridDim[1]*gridDim[2] + ity*gridDim[2] + itz,<br>
rho);<br>
}<br>
}<br>
}<br>
<br>
image->SetSpacing(sX, sY, sZ);<br>
<br>
image->Print(cerr);<br>
<br>
return 1;<br>
}<br>
<br>
<br>
<br>
<br>
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</blockquote></div><br></div>