render new volume on same plot

Hi all,

I would like to use vedo for volumetric rendering, but I would like to update the plot with a new volume render based off a slider value input. So, as the slider is moved, a new volume is rendered and displayed. Idea looks like this:

from vedo.pyplot import plot, histogram, show
from vedo import Volume, buildLUT, Plotter
import numpy as np
import nibabel as nib
import vtk
from vtk.util.numpy_support import vtk_to_numpy
import time
import vedo
import torch

# create slider
def slider1(widget, event):
    
    # get slider value
    value = widget.GetRepresentation().GetValue()
    value = value/100

    # linear interpolate between the two coords
    z = z_0*value + z_1*(1-value)

    # run interpolation
    moved = decodeZ(z, moving, model)

    # create the volume 
    vol = Volume(moved, c=bodyColors,  mapper='fixed')
    vol.mapper().SetClippingPlanes(planes)

    # plot
    plt.show(vol, interactive=False, camera=cam2, bg='black')

# initialize volume
vol = Volume(img, c=bodyColors,  mapper='fixed')
vol.mapper().SetClippingPlanes(planes)

# add slider
plt.addSlider2D(slider1, 0, 100, value=0,
            pos="bottom-right", title="Interpolate", c='blue')

plt.show(vol, interactive=True, camera=cam2, bg='black')

However, when the slider is moved, this gives the following error:

Traceback (most recent call last):
  File "volMotion.py", line 138, in slider1
    plt.show(vol, interactive=False, camera=cam2, bg='black')
  File "/home/savjani/anaconda3/lib/python3.8/site-packages/vedo/plotter.py", line 2354, in show
    self.allowInteraction()
  File "/home/savjani/anaconda3/lib/python3.8/site-packages/vedo/plotter.py", line 778, in allowInteraction
    self.interactor.DestroyTimer(self._repeatingtimer_id)
TypeError: DestroyTimer argument 1: an integer is required (got type NoneType)

There is likely a better way to update the plt with the new rendered volume, right? Thanks!

[marcomusy]

From the next release you’ll be able to do simply:

plt.addSlider2D(slider1, 0, 10, value=5, title="Interpolate", c='blue7', delayed=True)

[rsavjanimdphd]

@marcomusy - amazing, thank you so much! This is exactly what I was looking for.