Sun_direction?

Coding Python Support
1

Trying to figure out the sun_direction vector
If there is anybody who knows how to get the right vector for the sun direction please let me know.
if i look in the documentation it should be in
nodes[“Sky Texture”].sun_direction and be saved in 3 vectors
but if i check the console it only shows me one vector
from -1 to 1.
I dont get it

also you can not access the sun_direction via nodes.
the vector you can plug in is only the position, rotation and scale for the whole sky texture.
if you rotate it it will change the rotation / sun position but it will not change the color.

it would make more sense if the vector would change the sun direction instead of turning the horizon upside down.

what i wanted to do is to connect the Sun_direction (object) to the Sun_direction (Sky texture)
like it is in Blender internal when you turn on sky and atmosphere.
but in cycles it doesnt work that way

i was trying to connect it via drivers and it works (a little) but the sky texture doesnt respond as expected.

any help would be nice!

2

The easy way, find the values in the matrix!
Run script!

import bpy

if bpy.context.scene.world.use_nodes:
if bpy.context.object.type == “LAMP”:
if bpy.context.object.data.type == “SUN”:
lampob = bpy.context.object
else:
lamp = bpy.data.lamps.new(“Sun”, “SUN”)
lampob = bpy.data.objects.new(“SunRig”, lamp)
bpy.context.scene.objects.link(lampob)
#
mw = [i[:] for i in bpy.context.object.matrix_world[:]]
skynodes = [node for node in bpy.context.scene.world.node_tree.nodes[:] if node.type == “TEX_SKY”]
if len(skynodes) < 1:
shader = bpy.context.scene.world.node_tree.nodes.new(“ShaderNodeTexSky”)
bgnode = [node for node in bpy.context.scene.world.node_tree.nodes[:] if node.type == “BACKGROUND”][0]
bpy.context.scene.world.node_tree.links.new(shader.outputs[‘Color’], bgnode.inputs[‘Color’])
else:
shader = skynodes[0]
shader.sun_direction[0] = mw[0][2]
shader.sun_direction[1] = mw[1][2]
shader.sun_direction[2] = mw[2][2]

else:
print(“The world have not nodes!”)

3

http://www.pasteall.org/43238

4

kaicent,
The easiest way to do what you want is toinstall the ‘Sun Position’ addon located here:
wiki.blender.org…/3D_interaction/Sun_Position
It allows you to bind Cycles’ sky texture to a sun lamp and/or objects and animate the whole
thing by applying keyframing to the UI values.

Additionally, the nodes[“Sky Texture”].sun_direction vector is correct as it is a normalized 3D vector.
Based on a ‘unit sphere’, the vector is meant to indicate direction. To project a sun object 20 units
into Blender’s world space, you need only to multiply the sun_direction vector by a radius value,
i.e., object_location = sun_direction * 20.

Following is a simple test that should be run from the python console. It allows you
to place a sphere in the same direction as the sun in the sky texture. Here’s the setup:
| 1. Select Cycles as the renderer.
| 2. Make sure a Sky Texture exists called ‘Sky Texture’ in the World panel.
| 3. Move your camera to the world center, location (0,0,0).
| 4. After running the code below, do the following:
| a. right click on the camera to select it,
| b. then <Shift> right-click on the sphere that was created.
| c. Next, press <Ctrl>T and select ‘Track to constraint’.
| This will keep the camera pointing towards the sphere to
| verify the sun position from the viewport.
| 5. At this point you can keep running the set_sun_position function
| from the console changing any of the values to update the texture rotation
| and the object location.

import bpy
import math

def degToRad(angleDeg):
    return (pi * angleDeg / 180.0)

def set_sun_position(elevation, azimuth, radius):
    sd = bpy.data.worlds['World'].node_tree.nodes['Sky Texture'].sun_direction
    theta = pi / 2 - degToRad(elevation)
    phi = degToRad(-azimuth)
    sd.x = sin(phi) * sin(-theta)
    sd.y = sin(theta) * cos(phi)
    sd.z = cos(theta)
    return sd * radius
    
bpy.ops.mesh.primitive_uv_sphere_add(segments=32, ring_count=16, size=1.0, location=(10, 0, 0))
obj = bpy.context.active_object


# Set sun elevation to 30 degrees and azimuth 90 with sun object at
# a distance of 20 blender units from the world center.
obj.location = set_sun_position(30, 90, 20)