Implementing click_callback Functionality(Lack of clarity/focused example script)

[DhruvaRajwade]

• K3D version: 2.15.2(installed via conda-forge)
• Python version:Python 3.9.12
• Operating System: Arch Linux, Kernel: 6.1.1-arch1-1

Description

I was studying the mesh_callback example, linked here. I wanted to implement the click functionality to display metadata about a node when a graph is created, but could not get the on_click functionality to work.

Here is an example graph(Z=0), and what I was trying to do is get some metadata using the on_click callback when a point is clicked.

What I Did

I had a list of points(x,y,0). I converted them into a numpy array. I also had an array with areas for each set of Co-ordinates.
Here is the code I tried.

plot = k3d.plot()
object = k3d.points(xyz_coords, point_size=2)
plot += object
plot.mode = 'callback'
obj = plot.objects[0]
def display_area(obj):
  for i in range(31):
    if obj.positions == obj.positions[i]:
      point_id = i
    else:
        point_id=-1
  if point_id==-1:
    pass
  else:        
    area = areas[point_id]
    print(f"The area of the selected point is {area}")
obj.click_callback = display_area
plot.display()

I understand I must be doing something wrong(my display_area function seems very dodgy). What should I do to get the areas when I click on a point?
(I don't need the points to be exactly the size as their areas denote, they are merely for a graph representation with areas as features)

[artur-trzesiok]

Hi!

Your example is not working because k3d.points is not a DrawableWithCallback object

K3D-jupyter/k3d/objects.py

Line 181 in 5052d60

class DrawableWithCallback(Drawable):

)

So K3D at this moment simply dosen't support callbacks for

• k3d.points,
• k3d.line,
• k3d.lines,
• k3d.stl,
• k3d.text,
• k3d.text2d,
• k3d.label,
• k3d.texture_text,
• k3d.vector_field,
• k3d.vectors,
• k3d.volume,
• k3d.mip,

callbacks are available for:

• k3d.marching_cubes
• k3d.mesh
• k3d.surface
• k3d.texture
• k3d.voxels
• k3d.sparse_voxels
• k3d.voxels_group

It is visible in code execution:

I will try to add that to documentation too.

[DhruvaRajwade]

Thank you for the prompt reply! One last query, will callback support be added for the k3d.points object in the near future?

[artur-trzesiok]

That will be dedicaded mechanism just for points (goal is to calculate ray-sphere intersection rather than ray-mesh). But many people use k3d.points with milions of points so even here I should have some octree... It is not stright forward

[artur-trzesiok]

Good news! BVH that we use has support for points - https://gkjohnson.github.io/three-mesh-bvh/example/bundle/pointCloudIntersection.html

I feel we can do that in k3d soon but I don't want to make a promises :)

[artur-trzesiok]

btw my benchmark data to points callback- 24m of points (credits: https://sketchfab.com/3d-models/recovering-oak-point-cloud-version-f6dd3f2b081b483bb3f40b6b931016fd )

[artur-trzesiok]

Click callback functions #409

Callback "on hover" to python. Green boxes shows BVH Tree [for debug purpose only] on 8 mln of points: