Point Clouds

Point clouds are one of the core structures in Polyscope. In addition to simply displaying the points, Polyscope can show any number of scalar, vector, or color quantities associated with the points.

As always, try clicking on a point to see the data associated with that point.

Registering a point cloud

Example: a point cloud of random points

import numpy as np
import polyscope as ps
ps.init()

# generate some points
points = np.random.rand(100, 3)

# visualize!
ps_cloud = ps.register_point_cloud("my points", points)
ps.show()

# with some options
ps_cloud_opt = ps.register_point_cloud("my points", points, 
                                       radius=0.02, point_render_mode='quad')
ps.show()

register_point_cloud(name, points, enabled=None, radius=None, point_render_mode=None, color=None, material=None)

Add a new point cloud structure to Polyscope.

• name is the name for the structure, as a string
• points is an N x 3 numpy array of point locations

Additional optional keyword arguments:

• enabled boolean, is the structure enabled initially
• radius float, a size for the points relative to the scene length scale (use set_radius(val, relative=False) for absolute units)
• color float 3-tuple, default color values for the points as rgb in [0,1]
• material string, name of material to use for cloud

if not specified, these optional parameters will assume a reasonable default value, or a persistent value if previously set.

2D point clouds are also supported, see 2D data.

As with all structures, there is also get_point_cloud("name"), has_point_cloud("name"), and remove_point_cloud("name").

Updating a point cloud

The locations of the points in a point cloud can be updated with the member function update_point_positions(newPositions). All quantities will be preserved. Changing the number of points in the cloud is not supported, you will need to register a new cloud (perhaps with the same name to overwrite this one).

Example: update positions (continued from above)

new_pos = np.random.rand(100, 3)
ps_cloud.update_point_positions(new_pos)
ps.show()

PointCloud.update_point_positions(newPos)

Update the point positions in a point cloud structure. newPos must be valid input as to initially construct a point cloud, with the same number of points.

Point render mode

By default, Polyscope renders point clouds with a sphere for each point. However, for large point clouds (for instance, > 500,000 points, or on low-end hardware), this sphere rendering may become prohibitively expensive and lead to a laggy interface. As an alternative, points can be rendered as a small quad per-point, which is more efficient (for instance, it renders in real-time with 20,000,000+ points on my mid-range GPU).

The point render mode setting specifies which style is used:

• sphere a small sphere is drawn for each point (default)
• quad a small quad is drawn for each point

PointCloud.set_point_render_mode(newVal)

Set the the rendering method used to draw each point. Pass the string name of the style to use. One of 'sphere' (default) or 'quad'.

As usual, this can also be set as a keyword argument when the point cloud is registered, like register_point_cloud('my points', data, point_render_mode='quad').

There is also a corresponding get_point_render_mode().

Options

Options control the appearance of the cloud. These options can also be passed as keyword arguments to the initial register_point_cloud(), as noted above. See structure management for options common to all structures such as enabling/disabling, transforms, and transparency.

Parameter	Meaning	Getter	Setter	Persistent?
point radius	size of rendered points	get_radius()	set_radius(newVal, relative=True)	yes
point color	default color for points	get_color()	set_color(newVal)	yes
point render mode	how to draw points	get_point_render_mode()	set_point_render_mode(newVal)	yes
material	material for point	get_material()	set_material(newVal)	yes

Example: set options which affect the appearance of the point cloud

cloud = polyscope.register_point_cloud("my points", points)

cloud.set_enabled(False) # disable
cloud.set_enabled() # default is true

cloud.set_radius(0.02) # radius is relative to a scene length scale by default
cloud.set_radius(1.7, relative=False) # radius in absolute world units

cloud.set_color((0.3, 0.6, 0.8)) # rgb triple on [0,1]
cloud.set_material("candy")
cloud.set_transparency(0.5)

# alternately:
ps.register_point_cloud("my points 2", points, enabled=False, material='candy',
                        radius=0.02, color=(1., 0., 0.)
                        transparency=0.5)