[Paraview-developers] ParaView and double precision Rendering

[Lodron, Gerald]

Hi

Today i got an (maybe stupid) idea:

The solution of rescaling my double data to get correct viewing is not very elegant: All filter/sources settings will be in wrong relation (e.g. if I want to insert a sphere of radius 1, or if I want to measure my data using ruler, or if I want to watch my data in spreadsheet view)

Wouldn’t it better to write a “view plugin” where all data firstly is rescaled/mean subtracted before sending to 3d polydata mapper? In that case all filter settings, ruler and so on will also work like expected. I never wrote a view plugin but is this in principle possible? Or should I use a “representation plugin” for that.....

Any suggestions?

Best regards,
Gerald Lodron


Von: Berk Geveci [mailto:berk.geveci at kitware.com]
Gesendet: Dienstag, 14. April 2015 18:16
An: Lodron, Gerald
Cc: Paraview User (paraview at paraview.org); Paraview Developer (Paraview-developers at paraview.org)
Betreff: Re: [Paraview-developers] ParaView and double precision Rendering

OpenGL does not support double precision. VTK does not do anything special in handling large coordinates and passes them to OpenGL directly. So currently, you have to handle this yourself by rescaling your data.

Best,
-berk

On Mon, Apr 13, 2015 at 1:25 PM, Lodron, Gerald <Gerald.Lodron at joanneum.at<mailto:Gerald.Lodron at joanneum.at>> wrote:
Hello

I made a paraview reader plugin which loads Point data of type double from an ASCII file (can be choosen as checkbox in reader parameter gui). It is important that point data type is double since our values have a huge offset, e.g.

Coordinate in float:      3376382.75    -325198.59375   -121298.125
Coordinate in double: 3376382.849028525874      -325198.60899497801438  -121298.12806414699298
(same ASCII input file of type double, above printings come from spreadsheet view so loading is correct)
(all my points have such small changes, I definitely can see those small changes in 3d)

The problem is: I load the dataset once in float and once in double ( I checked result in spreadsheed view) I cannot see any differences in 3d renderer when I swap visibility of float and double input (but you can see in spreadsheet). Is the double precision rendering not correct/not supported?
Any ideas?

Best regards,

Gerald Lodron
Machine Vision Applications
DIGITAL - Institute for Information and Communication Technologies

JOANNEUM RESEARCH Forschungsgesellschaft mbH
Steyrergasse 17, 8010 Graz, AUSTRIA

phone:  +43-316-876-1751
fax: +43-316-876-1751
web:    http://www.joanneum.at/digital
e-mail: gerald.lodron at joanneum.at<mailto:gerald.lodron at joanneum.at>

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