Hi Brett, On 9 September 2014 09:59, Brett <[email protected]> wrote:
> :)...Sorry, it was a lost attempt at less confusion. Yes, I'm referring > to osgVolume where I have created a volume from a number of 2d images and I > want to vary the number of 2d images shown in the volume or make some of > them transparent to give an effect of slicing the model. > Regarding parametric variables, I meant if the volume was considered as a > 3d texture with a r parameterized texture coordinate from 0-1 along > direction of loading the slices, could I somehow vary the limits on the > parameterized r coordinate to limit the amount of the model shown for > effect of slicing, and if so, possibly the same for the s and t coordinates > to slice from different directions? Thank you. > osgVolume::VolumeTile has a osgVolume::Locator object that you can use to place the texture coordinates into model coordinates, and also the extents of area you want to be visualized. If you want the whole 3d image data to be displayed then you can share the same Locator between the VolumeTile and the ImageLayer, but if you want to visualize a subset then use a separate Locator, with the one of the ImageLayer placing the image into place in model coordinates, and the Locator on the VolumeTile settings the extents that you want to render. If you have a look at the osgvolume example where it wires up osgManipulator with the VolumeTile::Locator you can see an interactive example of how you can vary what part of the volume that is rendered. In the svn/trunk version of the OSG there is also a MultiPassTechnique that supports use of a convex hull geometry mesh to control the extents that are rendered. Robert.
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