volume rendering + transformation + perspective = artifacts

volume rendering + transformation + perspective = artifacts

Post by Tomas Lundber » Tue, 02 Jul 2002 18:45:33



I am using TGS Open Inventor 3.0 along with Volume Rendering 2.1 to
visualize medical volume data. I use 3D-texturing with view-aligned
slices.

Everything seems to work just fine until I do either a translation or
more than one rotation of the volume. Even if I multiply two rotations
into one before applying I get the problem.

The problem is that when I view  my volume (by rotating it with  mouse
input) it seems to become strangely "sliced" into small cubes and opaque
planes occur in seemingly random places. Also sections of the volume
disappears occasionally. This problem only occurs in perspective mode.
When using an orthographic camera everything looks fine.

Has anyone seen this problem before? Why can't I translate or do
multiple rotations to my volume when I watch it in perspective mode?

Any comments are gratefully accepted.
Thanks.

/Tomas

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volume rendering + transformation + perspective = artifacts

Post by Mike He » Wed, 03 Jul 2002 00:00:23



> I am using TGS Open Inventor 3.0 along with Volume Rendering 2.1 to
> visualize medical volume data. I use 3D-texturing with view-aligned
> slices.

> Everything seems to work just fine until I do either a translation or
> more than one rotation of the volume. Even if I multiply two rotations
> into one before applying I get the problem.

This sounds like a known problem in our bug list.
It has been fixed, but you will need to upgrade to
the current version:
    Open Inventor 3.1.1 and VolumeViz 3.0.1
(Note VolumeRendering was renamed VolumeViz)

-Mike
 TGS Inc, http://www.tgs.com

 
 
 

volume rendering + transformation + perspective = artifacts

Post by Tomas Lundbe » Tue, 30 Jul 2002 22:41:41




> > I am using TGS Open Inventor 3.0 along with Volume Rendering 2.1 to
> > visualize medical volume data. I use 3D-texturing with view-aligned
> > slices.

> > Everything seems to work just fine until I do either a translation or
> > more than one rotation of the volume. Even if I multiply two rotations
> > into one before applying I get the problem.

> This sounds like a known problem in our bug list.
> It has been fixed, but you will need to upgrade to
> the current version:
>     Open Inventor 3.1.1 and VolumeViz 3.0.1
> (Note VolumeRendering was renamed VolumeViz)

> -Mike
>  TGS Inc, http://www.tgs.com

Hello Mike.

I have upgraded to the latest version as you suggested, but the
problem remains. Do you have any other suggestions of what may cause
this problem?

/Tomas

 
 
 

volume rendering + transformation + perspective = artifacts

Post by Mike He » Wed, 31 Jul 2002 04:45:25



> I have upgraded to the latest version as you suggested, but the
> problem remains. Do you have any other suggestions of what may cause
> this problem?

Sorry, my mistake.  I am informed that this problem really is
fixed, but only in a post-3.0.1 patch for VolumeViz.  Please

patch.

-Mike
 TGS Inc, http://www.tgs.com

 
 
 

1. Volume rendering + transformation + perspective = artifacts.

I am using TGS Open Inventor 3.0 along with Volume Rendering 2.1 to
visualize medical volume data. I use 3D-texturing with view-aligned
slices.

Everything seems to work just fine until I do either a translation or
more than one rotation of the volume. Even if I multiply two rotations
into one before applying I get the problem.

The problem is that when I view  my volume (by rotating it with  mouse
input in my examiner viewer) it seems to become strangely "sliced"
into small cubes and opaque planes occur in seemingly random places.
Also sections of the volume disappears occasionally. This problem only
occurs in perspective mode. When using an orthographic camera
everything looks fine.

Has anyone seen this problem before? Why can't I translate or do
multiple rotations to my volume when I watch it in perspective mode?

Any comments are gratefully accepted.
Thanks.

/Tomas

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