Scene properties#

Each Scene has a background color and alpha, lights, and a camera.

[1]:

import fresnel
import math
scene = fresnel.Scene()
position = []
for i in range(6):
    position.append([2*math.cos(i*2*math.pi / 6), 2*math.sin(i*2*math.pi / 6), 0])

geometry = fresnel.geometry.Sphere(scene, position = position, radius=1.0)
geometry.material = fresnel.material.Material(solid=0.0, color=fresnel.color.linear([1,0.874,0.169]))
geometry.outline_width = 0.12
scene.camera = fresnel.camera.Orthographic.fit(scene)

Background color and alpha#

The default background color is black (0,0,0) and the background alpha is 0 (transparent).

[2]:

scene.background_color

[2]:

array([0., 0., 0.], dtype=float32)

[3]:

scene.background_alpha

[3]:

0.0

The background color is applied to any pixel in the output image where no object is present. Change the background alpha to only partially transparent:

[4]:

scene.background_alpha = 0.5

[5]:

fresnel.preview(scene)

[5]:

../../_images/examples_00-Basic-tutorials_04-Scene-properties_7_0.png

Set a solid background color:

[6]:

scene.background_alpha = 1.0
scene.background_color = fresnel.color.linear([0.592, 0.722, 0.98])

[7]:

fresnel.preview(scene)

[7]:

../../_images/examples_00-Basic-tutorials_04-Scene-properties_10_0.png

Light sources#

Light sources light the objects in the scene. Without lights, all objects are black.

[8]:

scene.lights.clear()

[9]:

fresnel.preview(scene)

[9]:

../../_images/examples_00-Basic-tutorials_04-Scene-properties_13_0.png

Fresnel defines several standard lighting setups that may be easily applied.

[10]:

scene.lights = fresnel.light.butterfly()

[11]:

fresnel.preview(scene)

[11]:

../../_images/examples_00-Basic-tutorials_04-Scene-properties_16_0.png

You can modify individual lights.

[12]:

scene.lights[0].direction = (-1, 0, 1)

[13]:

fresnel.preview(scene)

[13]:

../../_images/examples_00-Basic-tutorials_04-Scene-properties_19_0.png

Camera#

The camera defines the view to render into the scene. The default camera is an orthographic camera at (0,0,100), look at (0,0,0), and has a height of 100:

[14]:

scene2 = fresnel.Scene()
print(scene2.camera)

fresnel.camera.Orthographic(position=(0.0, 0.0, 100.0), look_at=(0.0, 0.0, 0.0), up=(0.0, 1.0, 0.0), height=100.0)

You can automatically fit an orthographic camera to the scene with camera.Orthographic.fit. Call it after defining all of the geometry in your scene.

[15]:

scene.camera = fresnel.camera.Orthographic.fit(scene)

A camera is defined by its position, look-at point, up vector and height of the view into the scene. All of these quantities are in scene coordinates.

[16]:

scene.camera = fresnel.camera.Orthographic(position=(0,0,2), look_at=(0,0,0), up=(0,1,0), height=6)
fresnel.preview(scene)

[16]:

../../_images/examples_00-Basic-tutorials_04-Scene-properties_25_0.png

You can modify these parameters individually.

[17]:

scene.camera.position = (3, 0, 10)
scene.camera.look_at=(3,0,0)

[18]:

fresnel.preview(scene)

[18]:

../../_images/examples_00-Basic-tutorials_04-Scene-properties_28_0.png

Print the full representation of the camera.

[19]:

print(repr(scene.camera))

fresnel.camera.Orthographic(position=(3.0, 0.0, 10.0), look_at=(3.0, 0.0, 0.0), up=(0.0, 1.0, 0.0), height=6.0)

You can copy and paste this text to reproduce the same camera elsewhere.

[20]:

scene.camera = fresnel.camera.Orthographic(position=(3.0, 0.0, 10.0),
                                           look_at=(3.0, 0.0, 0.0),
                                           up=(0.0, 1.0, 0.0),
                                           height=6.0)

This page was generated from a jupyter notebook. You can download and run the notebook locally from the fresnel-examples repository.