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[IDV #WNR-458825]: Problem w/volume rendering



Hi Katie-

> Thanks so much for getting back to me and for trying out my files on
> your system. Unfortunately, my network won't allow me to receive
> graphical attatchments (don't ask me why) so could you resend the
> attatchment either to my personal email or
> to this address but as part of a Word document? Thanks so much for all
> your help and patience.

I've cc'd your other email on this response with the attached image.

BTW, I fixed the problem with the display only showing up as a thin
column.  It was a problem with the projection as I suspected.  I
now make sure we are in the correct projection before calculating
the volume for rendering.  The fix is in the latest nightly build.

I also noted that your lat/lon points in the netcdf file don't
match up with shape of the topography image. The topography
image looks like southern Florida (except upside down and backwards),
but the lat/lon points put it in a smaller area, just east of Key West
(lats from 24.3762 to 24.82356, lons from -81.6238 to -81.17645).
It looks like it should go from about 24 to 27 and from -82 to -79 
from the topography. Maybe this was just meant to be a sample, but 
just wanted you to know in case it's not.  

Don
 
> -----Original Message-----
> From: Unidata IDV Support [mailto:address@hidden]
> Sent: Wednesday, April 23, 2008 5:47 PM
> To: Carbonari, Katie
> Cc: address@hidden
> Subject: [IDV #WNR-458825]: Problem w/volume rendering
> 
> Hi Katie-
> 
> > Thanks so much for your quick response.
> 
> This one took a little longer. ;-)
> 
> > We have been using the 64 bit version of Java, but we get the same
> problems when we run the 32 bit version (of course, we have to use a
> smaller data set of 250x250x50). If it's not too much trouble, could you
> try to render our data set on your setup? We're using a new machine (a
> Mac) and want to be sure that the problem is not with the way ours is
> configured. If you could do a volume rendering of the data (lwc) and
> send us a screen shot, we'd be very much appreciative. If you're
> successful, please let us know what you're using (os, graphics card).
> Enclosed is a screen shot of the same data in VAPOR. While VAPOR lacks a
> lot of the functions we need (that IDV has), it is giving excellent
> results in the volume rendering. Our goal is to get our clouds in IDV to
> look as good as the clouds in VAPOR.
> 
> I'm not sure you'll get as good as VAPOR, but I've attached a screen
> shot of what I was able to produce.  It took a long time because we do
> on the fly what VAPOR does when it transforms your netCDF file initially
> - put the data into display coordinate space.  We do it on the fly
> because you can display the data in any projection you want.
> 
> I also ran into the issue with it sometimes producing just a small
> column.  I think that's an issue with the projection changing when you
> display the data.  If you set the projection to the data space first
> (e.g. display a plan view of qc or something), then I don't think that
> will be an issue.  I'll look into that more closely when I get a chance.
> 
> My graphics card is an ATI Mobility Radeon X1400 w/ 512 Mb.  I am using
> the Texture3D.  Turning that off made a less pretty display.
> For the attached, I set the data range to be 150 to 247 and
> I set the transparency to be 50%.   The other person who
> had the problem with the Texture3D was also using a Mac.  He had a
> NVIDIA GeForce 8600M GT with 256 Mb RAM.
> 
> Don
> 
> -----Original Message-----
> > From: Unidata IDV Support [mailto:address@hidden]
> > Sent: Fri 4/18/2008 3:36 PM
> > To: Carbonari, Katie
> > Cc: address@hidden
> > Subject: [IDV #WNR-458825]: Problem w/volume rendering
> >
> > Hi Katie-
> >
> > > Hi Don. I have a few more questions concerning volume rendering I
> hope you can help me with.
> > >
> > > First off, a little background. I'm trying to do volume rendering of
> lwc (liquid water content, clouds) over terrain. Each file is a netCDF
> file (80 meg) that has 1250x1250x50 points of liquid water plus
> 1250x1250 of terrain elevation. There are 60 files total to be
> visualized (1 file=1min). There are several problems I've been having:
> > >
> > > 1) Even with 12 gig of memory allocated to IDV, often volume
> rendering runs out of memory, even at much courser resolutions. Are
> there any parameters I can change that will speed up the volume
> rendering?
> >
> > Does the memory monitor actually show 12 Gb allocated?  Are you
> > running a 64 bit version of Java?  The 32 bit version will only
> allocate 2 Gb.
> >
> > > 2) Sometimes IDV does not use the full 12 gigs allocated to it, but
> still takes a very long time to render. Is this just because my data set
> is so large?
> >
> > Volume rendering is very much a hog of memory.  To do the volume
> > rendering we have to retransform the entire dataset.  If these are
> > staggered WRF grids, that will be even worse because we need to
> destagger them.
> >
> > > 3) Occasionally, instead of getting the entire volume rendered, only
> 
> > > a small "chimney" will be visualized. It appears to be the full data
> 
> > > set but only over 1/20 of the proper area. Any ideas about what
> > > causes this? (Of course, I can't get it to do it now, so I don't
> > > have a screen shot to show you)
> >
> > I hate problems like that. ;-)  I can't think of anything off the top
> > of my head that would cause that.
> >
> > > 4) Once the data is fully loaded, I can't seem to make the clouds
> > > look like clouds. I want to control the volume to be colored by
> > > opacity, not color. If the lwc is below a certain threshold value, I
> 
> > > want those points to be totally transparent (ie, want to be able to
> > > see straight to the ground). Any advice on how to control the
> > > opacity in this way? (see attached photo of how our clouds currently
> 
> > > look; they are not very good-looking clouds)
> >
> > The image didn't come across, but here are a couple of suggestions.
> > First, use the  Visible Range in the display control to set the range
> > of the values you want to visualize.  Alternatively (or in addition
> > to), edit the color table and set the transparency for the range you
> > don't want to see to 100% and the values you want to see to 90%.  That
> 
> > will make those values you want to see more "cloudy".  Transparency is
> 
> > order dependent, so if you have other displays in the View, you'll
> > want to use the View->Bring to Front menu on the Volume Control so you
> can see the other displays.
> >
> > > Thank you so much for your time,
> >
> > Don
> > > -----Original Message-----
> > > From: Unidata IDV Support [mailto:address@hidden]
> > > Sent: Thu 4/17/2008 5:34 PM
> > > To: Carbonari, Katie
> > > Cc: address@hidden
> > > Subject: [IDV #WNR-458825]: Problem w/volume rendering
> > >
> > > Hi Katie-
> > >
> > > > Full Name: katie carbonari
> > > > Email Address: address@hidden
> > > > Organization: northrop grumman
> > > > Package Version: 2.5
> > > > Operating System: linux
> > > > Hardware:
> > > > Description of problem: Hello. I've been trying to do some volume
> rendering of clouds in IDV. Isosurface works fine (as you can see in the
> attatched picture) but volume rendering gives a gray cube. This gray
> cube doesn't change when I change various parameters (color range,
> transparency, etc). Any ideas on why this is happening? The 2 pics are
> of the same data file, so I don't know why the volume rendering doesn't
> give clouds.
> > >
> > > This is probably a graphics card issue.  What is the graphics card
> > > you are using?
> > >
> > > Try the following:
> > >
> > > - do the volume rendering
> > > - bring up the properties for the Volume Rendering control
> > > (Edit->Properties menu of the control).
> > > - Uncheck the Use Texture 3D property and click the OK button.
> > >
> > > Does that make your volume rendering appear?
> > >
> > > Don Murray
> > >
> > > Ticket Details
> > > ===================
> > > Ticket ID: WNR-458825
> > > Department: Support IDV
> > > Priority: Normal
> > > Status: Open
> > >
> > >
> > >
> > >
> > >
> > >
> >
> >
> > Ticket Details
> > ===================
> > Ticket ID: WNR-458825
> > Department: Support IDV
> > Priority: Normal
> > Status: Open
> >
> >
> >
> >
> >
> 
> 
> Ticket Details
> ===================
> Ticket ID: WNR-458825
> Department: Support IDV
> Priority: Normal
> Status: Open
> 
> 


Ticket Details
===================
Ticket ID: WNR-458825
Department: Support IDV
Priority: Normal
Status: Open

Attachment: volume.png
Description: PNG image