Accessing voxel grid data

[ianbaxter1]

Hi

If I have a voxel grid, by middle clicking I can see the fields and relevant resolutions. Now I want to see what the actual values are within these voxels.

If I have 5 million voxels I obviously don't want to view them all but can I access/view say the min/max density and min/max temperature of the voxel grid?

Cheers

[melazoma]

You can use Volume Reduce SOP to calculate the min/max values in volume primitives. You can also set it to store these values in primitive attributes to make them easily accesible in Attributes Spreadsheet / Details View.

Edited March 18, 2013 by melazoma

[bunker]

You can use the volumemax and volumemin expressions in the Textport. type: exhelp volume for a list of volume related expressions

[edward]

I use the Volume Slice SOP. This gives a 2D grid of points matching the voxels. If you look at the density attribute generated, you'll see the actual voxel values while the point colours give you an indication of how those values are changing.

[ianbaxter1]

Thanks for all the suggestions. Works a charm!

[Harsh M]

Hey Guys,

Any idea how to access OpenVDB voxel data ?

Cheers

Harsh

[edward]

Any idea how to access OpenVDB voxel data?

For what purpose? You can process the VDB primitives via various SOPs (incl. Volume VOP SOP), and you can evaluate specific voxels if you want via the new hou.VDB (subclass of hou.Prim) primitive class.

EDIT: As mentioned above, the various volume hscript expression functions as well.

[bunker]

nothing worked for me in hscript (12.5.316.22 osx), but it works fine in Pyhon.

myVdb = hou.node('/obj/geo1/vdbfrompolygons1').geometry().prims()[0]

myVdbSample = myVdb.sample((0,0,0))

print 'VDB Sample at 0,0,0 :' , myVdbSample

[Harsh M]

Thanks Edward and Julien.

hou.VDB worked perfect.

Cheers

H

[edward]

nothing worked for me in hscript (12.5.316.22 osx), but it works fine in Pyhon.

Strange, volumesample() seems to work for me.