Hi, I haven't looked at the data - I simply don't have the available time to go into this right now. I doubt its a bug, rather a limitation in the technique. Please understand the shader is a quick knock together. If it doesn't work perfectly in all situations than something I'm happy to except, it was never meant to be anything other than a basic example. There are large texts on the topic on volume rendering and lots of stuff online.
If you can wait, there are plans for the development of an osgVolume NodeKit, that will be a full blown implementation of various published techniques as well as few that probably come up with ourselves once we start pushing the start of the art. This project should be under way by the summer. Robert. On Jan 11, 2008 3:20 AM, hesicong2006 <[EMAIL PROTECTED]> wrote: > Thanks, and sorry for my poor English..... > To let the things clear, please P1.jpg attached. I draw three yellow > line to show the problem. Notice the red-yellow dot line, it starts from > the intersection of two yellow lines and goes in direction of the line > behind the head. You can the head becomes hollow when the line goes > through. If you try my volumedata, it will show you much more clearer. > > Gerrick Bivins wrote: > > Hi, > > If you are referring to the "slices" that you see, this is a typical > > artifact in volume rendering applications due > > to under-sampling (low number of polygon slices). A simple solution > > (not efficient though) is to increase the number of slices > > until the artifact goes away (usually 2*max_texture_dimension).There > > are other solutions (more efficient)out there > > as well...(The Real-Time volume Graphics > > <http://www.real-time-volume-graphics.org/> book is a great > > reference).If you are not talking about the > > slicing, it's not very clear what you mean by "And notice the > > head,it's a little strange" > > biv > > On Jan 10, 2008 10:59 AM, hesicong2006 <[EMAIL PROTECTED] > > > <mailto:[EMAIL PROTECTED]>> wrote: > > > > Thanks Robert and could you try my volume data? (Sorry its too big for > > email, but you can download from > > http://www.hesicong.net/volumedata.rar) > > You can see the animated failure. > > I recaptured the image, P1.jpg and P2.jpg use the default setting you > > provided. In P3, I decreased the sampleDensity, but it still have the > > problem. > > At last my computer is: > > CPU: Intel Core 2 Duo Q6600 > > RAM: 3G > > GPU: Geforce 8800GTS 320M with 169.09 driver under XP. I think it will > > not be hardware failure or driver failure. Is that caused by > > projection > > view? I tried to modify it to ortho view, but I even can't see the > > volume cube~~~ > > > > At last the command I use is here, thanks again for your help. > > osgvolumed --shader --replace-alpha-with-luminance --images 000.TIF > > 001.TIF 002.TIF 003.TIF 004.TIF 005.TIF 006.TIF 007.TIF 008.TIF > > 009.TIF > > 010.TIF 011.TIF 012.TIF 013.TIF 014.TIF 015.TIF 016.TIF 017.TIF > > 018.TIF > > 019.TIF 020.TIF 021.TIF 022.TIF 023.TIF 024.TIF 025.TIF 026.TIF > > 027.TIF > > 028.TIF 029.TIF 030.TIF 031.TIF 032.TIF 033.TIF 034.TIF 035.TIF > > 036.TIF > > 037.TIF 038.TIF 039.TIF 040.TIF 041.TIF 042.TIF 043.TIF 044.TIF > > 045.TIF > > 046.TIF 047.TIF 048.TIF 049.TIF 050.TIF 051.TIF 052.TIF 053.TIF > > 054.TIF > > 055.TIF 056.TIF 057.TIF 058.TIF 059.TIF 060.TIF 061.TIF 062.TIF > > 063.TIF > > 064.TIF 065.TIF 066.TIF 067.TIF 068.TIF 069.TIF 070.TIF 071.TIF > > 072.TIF > > 073.TIF 074.TIF 075.TIF 076.TIF 077.TIF 078.TIF 079.TIF 080.TIF > > 081.TIF > > 082.TIF 083.TIF 084.TIF 085.TIF 086.TIF 087.TIF 088.TIF 089.TIF > > 090.TIF > > 091.TIF 092.TIF 093.TIF 094.TIF 095.TIF 096.TIF 097.TIF 098.TIF > > 099.TIF > > 100.TIF 101.TIF 102.TIF 103.TIF 104.TIF 105.TIF 106.TIF 107.TIF > > 108.TIF > > 109.TIF 110.TIF 111.TIF 112.TIF 113.TIF 114.TIF 115.TIF 116.TIF > > 117.TIF > > 118.TIF 119.TIF 120.TIF 121.TIF 122.TIF 123.TIF 124.TIF 125.TIF > > 126.TIF > > 127.TIF 128.TIF 129.TIF 130.TIF 131.TIF 132.TIF 133.TIF 134.TIF > > 135.TIF > > 136.TIF 137.TIF 138.TIF 139.TIF 140.TIF 141.TIF 142.TIF 143.TIF > > 144.TIF > > 145.TIF 146.TIF 147.TIF 148.TIF 149.TIF 150.TIF 151.TIF 152.TIF > > 153.TIF > > 154.TIF 155.TIF 156.TIF 157.TIF 158.TIF 159.TIF 160.TIF 161.TIF > > 162.TIF > > 163.TIF 164.TIF 165.TIF 166.TIF 167.TIF 168.TIF 169.TIF 170.TIF > > 171.TIF > > 172.TIF 173.TIF 174.TIF 175.TIF 176.TIF 177.TIF 178.TIF 179.TIF > > 180.TIF > > 181.TIF 182.TIF 183.TIF 184.TIF 185.TIF 186.TIF 187.TIF 188.TIF > > 189.TIF > > 190.TIF 191.TIF 192.TIF 193.TIF 194.TIF 195.TIF 196.TIF 197.TIF > > 198.TIF > > 199.TIF 200.TIF 201.TIF 202.TIF 203.TIF 204.TIF 205.TIF 206.TIF > > 207.TIF > > 208.TIF 209.TIF 210.TIF 211.TIF 212.TIF 213.TIF 214.TIF 215.TIF > > 216.TIF > > 217.TIF 218.TIF 219.TIF 220.TIF 221.TIF 222.TIF 223.TIF 224.TIF > > 225.TIF > > 226.TIF 227.TIF 228.TIF 229.TIF 230.TIF 231.TIF 232.TIF 233.TIF > > 234.TIF > > 235.TIF 236.TIF 237.TIF 238.TIF 239.TIF 240.TIF 241.TIF 242.TIF > > 243.TIF > > 244.TIF 245.TIF 246.TIF 247.TIF 248.TIF 249.TIF 250.TIF 251.TIF > > 252.TIF > > 253.TIF 254.TIF 255.TIF > > > > Robert Osfield wrote: > > > Hi, > > > > > > I'm the author of the osgvolume example. Its just a quick > > > prototype/proof of concept, and one I haven't touched in the > > last year > > > or two so its a bit cold. The visual errors on the frame region > > > you've observed aren't ones I've seen before, but then I've never > > > played with a volume dataset that has a frame in it. I'm afraid I > > > can't think of any obvious failure modes that would introduce these > > > artefacts. Try different hardware/OpenGL drivers/OS to see if the > > > artefacts changes. As for the head region, I can't spot any > > problem. > > > > > > Robert. > > > > > > On Jan 10, 2008 6:40 AM, hesicong2006 <[EMAIL PROTECTED] > > <mailto:[EMAIL PROTECTED]>> wrote: > > > > > >> Hi everyone: > > >> I'm now doing a medical application using volume rendering > > technology. > > >> osgVolume example gives me a very good start, thanks to people who > > >> contributes to this example. But I found some image errors (see > > >> attachments) , In p1.jpg, see the red circle, the outboder line > > bends. > > >> In p2.jpg, the line bends more than that in p1.jpg. And notice > > the head, > > >> it's a little strange. I tried to fix this problem, but I still > > can't > > >> figure out why it happens to be like this.Does someone can help > > me or > > >> point out why it appears like this? > > >> Thanks very much! > > >> > > >> _______________________________________________ > > >> osg-users mailing list > > >> [email protected] > > <mailto:[email protected]> > > >> > > > > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > > > > <http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org> > > >> > > >> > > >> > > > > > > > > > > > > _______________________________________________ > > osg-users mailing list > > [email protected] > > <mailto:[email protected]> > > > > > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > > > > > > _______________________________________________ > osg-users mailing list > [email protected] > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > > _______________________________________________ osg-users mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
