Gumballs

Spheres rendered as gumballs made from a Monte Carlo simulation with HOOMD.

• Geometry: geometry.Sphere: radius = 0.5

  • material: primitive_color_mix = 1.0, roughness = 0.2, specular = 0.8

  • positions: output of a HOOMD simulation

  • colors: randomly assigned from a set of gumball colors

• Lighting: light.lightbox with an additional light

• Rendered with: tracer.Path: samples = 256, light_samples = 64 on the GPU

Source code

# Copyright (c) 2016-2024 The Regents of the University of Michigan
# Part of fresnel, released under the BSD 3-Clause License.

"""Gumballs example scene."""

import fresnel
import numpy as np
from matplotlib.colors import LinearSegmentedColormap
import PIL
import sys
import os

# First, we create a color map for gumballs.
colors = [
    '#e56d60',
    '#ee9944',
    '#716e80',
    '#eadecd',
    '#cec746',
    '#c0443f',
    '#734d56',
    '#5d5f7b',
    '#ecb642',
    '#8a9441',
]
cmap = LinearSegmentedColormap.from_list(name='gumball',
                                         colors=colors,
                                         N=len(colors))

# Next, we gather information needed for the geometry.
position = np.load('gumballs.npz')['position']
np.random.seed(123)
color = fresnel.color.linear(cmap(np.random.rand(len(position))))
material = fresnel.material.Material(
    primitive_color_mix=1.0,
    roughness=0.2,
    specular=0.8,
)

# We create a fresnel scene and its geometry.
scene = fresnel.Scene()

geometry = fresnel.geometry.Sphere(
    scene,
    position=position,
    radius=0.5,
    color=color,
    material=material,
)

# Configure camera and lighting.
scene.camera = fresnel.camera.Perspective(position=(0, 0, 25),
                                          look_at=(0, 0, 0),
                                          up=(0, 1, 0),
                                          focal_length=0.5,
                                          f_stop=0.25)
scene.camera.focus_on = (0, 0, 5.6)
scene.lights = fresnel.light.lightbox()
scene.lights.append(
    fresnel.light.Light(direction=(0.3, -0.3, 1),
                        color=(0.5, 0.5, 0.5),
                        theta=np.pi))

if 'CI' in os.environ:
    samples = 1
else:
    samples = 128

# Execute rendering.
out = fresnel.pathtrace(scene, w=600, h=600, samples=samples, light_samples=64)
PIL.Image.fromarray(out[:], mode='RGBA').save('gumballs.png')

if len(sys.argv) > 1 and sys.argv[1] == 'hires':
    out = fresnel.pathtrace(scene,
                            w=1500,
                            h=1500,
                            samples=256,
                            light_samples=64)
    PIL.Image.fromarray(out[:], mode='RGBA').save('gumballs-hires.png')

Author

Bradley Dice