Volume from RGBA numpy array

Hi,

I was wondering whether vtkplotter supports indicating the color for each pixel separately in a Volume.

This for example doesn’t work as it renders a red structure (should be blue):

from vtkplotter import show, Volume
import numpy as np

import matplotlib as mpl
from matplotlib import cm

norm = mpl.colors.Normalize(vmin=0, vmax=255)
scalarMap = cm.ScalarMappable(norm=norm, cmap='Blues')

im = np.random.randint(0,255,(10,11,12)).astype(np.uint8)
im_rgb = scalarMap.to_rgba(im.flatten()).reshape(im.shape+(4,))

vol = Volume(im_rgb,shape=im_rgb.shape[:3],mode=1)

show(vol)

Thanks a lot! Best, Marvin

[m-albert]

Those are great suggestions! (Sorry that I forgot to answer earlier)

It’s great to see how vedo is becoming even more powerful and mature 😃. Thanks so much!

[marcomusy]

PS: Consider also removing the nested loops with:

import vtk
from vtkplotter import Volume
import numpy as np

vol = Volume(None, shape=(10,11,12), mode=0)
vol.alpha(0.4).jittering(False)
vol.GetProperty().IndependentComponentsOff()
vol.GetProperty().SetInterpolationTypeToNearest()

vol.imagedata().AllocateScalars(vtk.VTK_UNSIGNED_CHAR, 4)
arr = vol.getPointArray()
arr[:] = np.random.randint(0,255, (10*11*12,4)).astype(np.uint8)

vol.show()

and also save memory with vtk.VTK_UNSIGNED_CHAR