<DIV id=RTEContent> <DIV id=RTEContent> <DIV><BR>Hello again Marc,</DIV> <DIV> </DIV> <DIV>Regarding visualizing the model in wireframe.</DIV> <DIV> </DIV> <DIV>I dont understand your suggestion.</DIV> <DIV> </DIV> <DIV>If there is a closed surface ( or even a concave or convex open surface ) you would always find polygons with normals opposite to each other.</DIV> <DIV> </DIV> <DIV>For example:</DIV> <DIV> </DIV> <DIV>two opposite faces of a cube.</DIV> <DIV> </DIV> <DIV>I dont know what kind of surfaces you were talking about. Could u please explain further ?</DIV> <DIV> </DIV> <DIV>If you were talking of adjacent polygons with normals facing in opposite directions,</DIV> <DIV>this is hardly possible in the scan of a human body surface. I also visualized my model in wirefram, i found no polygons adjacent like this. Also the places where the cracks are present do not abide to this property.</DIV>
<DIV> </DIV> <DIV>I have attached an image showing the cracks.</DIV> <DIV> </DIV> <DIV>Regards,</DIV> <DIV> </DIV> <DIV>Deepak Roy</DIV> <DIV> </DIV> <DIV> </DIV> <DIV> </DIV> <DIV> </DIV> <DIV> </DIV> <DIV> </DIV> <DIV><BR><B><I>Marc Cotran <marc@cotran.ca></I></B> wrote:</DIV> <BLOCKQUOTE class=replbq style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #1010ff 2px solid">Deepak Roy wrote:<BR><BR>> Hello Marc,<BR>> Thanks for the reply.<BR>> I started working back on this texture issue now, which set aside due <BR>> to other high priority work.<BR>> But when i visualize these surface models, in third party vrml viewers <BR>> the texture comes out well. Its only in my program that i find these <BR>> pattern of cracks.<BR>> What do you think could be the problem ?<BR><BR><BR>Did you try visualizing in wireframe? Do there seem to be any polygons <BR>with normals facing the wrong way? Could you
tell me (in pseudo code) <BR>what vtkObjects you are using in your pipeline? Which version of VTK are <BR>you using and on what platform?<BR><BR>Marc<BR><BR>><BR>> */Marc Cotran <MARC@COTRAN.CA>/* wrote:<BR>><BR>> Hi Deepak,<BR>><BR>> I had experienced similar results before and concluded that the<BR>> polygon<BR>> normals were the culprit. I would suggest visualizing the polydata<BR>> mesh<BR>> in wireframe to see if some of your polygons are oriented opposite to<BR>> the others. I am not sure this is what you're dealing with, but it<BR>> might<BR>> explain your problem. As for a potential solution... I am at a loss.<BR>><BR>> Should you figure out the problem, I'd love to know the solution.<BR>><BR>> HTH,<BR>><BR>> Marc<BR>><BR>> Deepak Roy wrote:<BR>> ><BR>> > Hello everyone,<BR>> ><BR>> > I have had a hard time trying to fix this texture display problem.<BR>> ><BR>> > Attached is a
part of the texture image i am using for the human<BR>> body.<BR>> > I have removed the face and other parts due to some identity<BR>> revealment<BR>> > problems.<BR>> ><BR>> > But the image gives an idea of the problem i am facing. Look at the<BR>> > image and you will see the cracks on the texture.<BR>> ><BR>> > when i visualize the same model in some other standard graphics<BR>> software<BR>> > like Rapid Forms, the texture shows up with out any cracks.<BR>> ><BR>> > I have tried all the possible options with vtkTexture but still<BR>> i could<BR>> > not fix the problem.<BR>> ><BR>> > /"Can anyone explain this phenomenon ? "/<BR>> ><BR>> > One more point to note, which i also mentioned in my previous<BR>> posting to<BR>> > the mailing list, is that exactly the same pattern of cracks<BR>> appear in<BR>> > every model i load.<BR>> ><BR>> > I suspect, it
is got to do with clamping or interpolation.<BR>> ><BR>> > Please help me fix this problem.<BR>> ><BR>> > Thanks in Advance.<BR>> ><BR>> > Regards,<BR>> ><BR>> > Deepak Roy<BR>> ><BR>> ><BR>> ><BR>> ><BR>> > Yahoo! Music Unlimited - Access over 1 million songs. Try it free.<BR>> ><BR>> ><BR>> ><BR>> ------------------------------------------------------------------------<BR>> ><BR>> > Subject:<BR>> > Texture Mapping Problem....Please Help !!!!!<BR>> > From:<BR>> > Deepak Roy<BR>> > Date:<BR>> > Fri, 14 Oct 2005 15:42:33 -0700 (PDT)<BR>> > To:<BR>> > vtkusers@vtk.org<BR>> ><BR>> > To:<BR>> > vtkusers@vtk.org<BR>> ><BR>> ><BR>> > Hi,<BR>> ><BR>> > I am trying to displaying a 3D surface of a human body with<BR>> texture, all<BR>> > captured from a 3D scan. I am using vtkTecture
to assosciate the<BR>> actor<BR>> > with the texture.<BR>> ><BR>> > The problem is:<BR>> ><BR>> > I see a pattern of cracks on surface when displayed with<BR>> texture. These<BR>> > cracks are not present in the basic geometry of the model as the<BR>> surface<BR>> > when visualised without texture appears fine and smooth. I am<BR>> 100% sure<BR>> > that this is the problem with texture mapping.<BR>> ><BR>> > One more thing that was wierd was that i see more or less the same<BR>> > pattern of tracks on each model i display.<BR>> ><BR>> > Could anyone explain the reason why this is happening?<BR>> ><BR>> > I guess the problem is with the edge clamping used while mapping<BR>> the<BR>> > texture. But vtkTexture does not give me any control on how to<BR>> change<BR>> > these parameters.<BR>> ><BR>> > How can i change the these parameters and control the way
texture<BR>> > mapping is done. Is there an easy way to do this?<BR>> ><BR>> > Thanks in Advance.<BR>> ><BR>> > Regards<BR>> ><BR>> > Deepak<BR>> ><BR>> ><BR>> > Yahoo! Music Unlimited - Access over 1 million songs. Try it free.<BR>> ><BR>> ><BR>> ><BR>> ------------------------------------------------------------------------<BR>> ><BR>> ><BR>> ><BR>> ------------------------------------------------------------------------<BR>> ><BR>> > _______________________________________________<BR>> > This is the private VTK discussion list.<BR>> > Please keep messages on-topic. Check the FAQ at:<BR>> http://www.vtk.org/Wiki/VTK_FAQ<BR>> > Follow this link to subscribe/unsubscribe:<BR>> > http://www.vtk.org/mailman/listinfo/vtkusers<BR>><BR>><BR>> Yahoo! Photos – Showcase holiday pictures in hardcover<BR>> Photo Books <BR>> <HTTP:
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