Sun Position

Sun Position allows positioning and animating the Sun (to a certain degree of accuracy), to simulate real-world natural lighting. It uses physical characteristics to position the Sun in the scene: geographic location, time and date. It is based on the Earth System Research Laboratory’s online calculator.

Activation

Activate the extension by going to the Extensions section of the user preferences, searching for “Sun” and clicking the check box to the left of the result.

Interface

Located in the Properties → World → Sun Position panel.

Usage

This add-on has two distinct modes of operation: the Sun Object Mode allows you to animate the Sun realistically, while the Environment Mode is useful for synchronizing a sun light to an environment texture.

The usage mode can be selected from the top of the Sun Position panel.

Sun Object Mode

This is the mode by default. After selecting the time and place, you can set up a sun light, a sky texture, and a collection to serve as visualization.

Use Object

Select the Sun object which will be placed according to the chosen time and place. Its position will be updated every time you change the location or time, and you can thus create animations by setting keyframes on them.

Use Collection

Select a collection of objects to be placed around the scene for visualization. Two options are available: analemma and diurnal.

Note: it is recommended to create a collection in the scene, and to move the objects into this collection. If you wish to create several visualizations, create as many collections as needed, select them in turn and choose the right settings. Once deselected, a collection will stay in place.

Analemma

The analemma is a visualization of the position of the Sun in the sky around the year for a given time of the day. In other words, it is like a time lapse picture of the sky over a year, with the Sun appearing multiple times at the same time of the day.

The analemma was used here to match this picture.

Diurnal

This option allows you to visualize the trajectory of the Sun in the sky during a single day.

Sky Texture

Select a Sky Texture node in the World shading node tree. It will be set up to match the Sun animation. This is useful if you want to have a simple sky texture matching a sun light’s position.

Location

In order for the Sun to be placed correctly, you need to choose a place on Earth where the scene is located. This place is represented by two coordinates, Longitude (East / West) and Latitude (North / South). They are expressed in degrees, from -180° to +180° for the longitude, and from -90° to 90° for the latitude. The coordinates match those found on such databases as OpenStreetMap or Google Maps. You may enter and animate them manually, or paste them in.

Entering Coordinates

In the Location panel, enter Latitude and Longitude coordinates corresponding to the location you wish to simulate. A simpler way is to go to an online map such as OpenStreetMap, copy the coordinates from there, and paste them into the Enter Coordinates field. They will be parsed automatically.

Another source is Wikipedia. Suppose you want to render the Barcelona Pavilion by Mies van der Rohe. You can copy the coordinates from the article and paste them into Blender.

Copy the coordinates from Wikipedia.	And paste them into Blender to have them parsed.

North Offset

By default, the North points to the Y axis in the scene (to the top of the screen in top view). But sometimes, you may have modeled it in another orientation. In that case, you may enter a North Offset, to change the orientation of the scene. Show North toggles a dashed line pointing to the North in the 3D Viewport, to help you visualize the cardinal directions.

Setting the Time

After selecting the location on Earth, select or animate the date and time. This is fairly straightforward, but care must be taken to match the Time zone and Daylight Saving to the moment you wish to simulate. Time entered is the local time, but the global, UTC time may be displayed below as well.

Note: time is stored in decimal format instead of hour:minute:second. To match a time in that format, look at the label Local.

Environment Mode

Instead of simulating the position of the Sun for a real location and time, this mode simply locks an environment texture with a sun light object. It is useful if you want to increase the contrast in a texture, by using an additional Sun.

Synchronizing the Sun Object to the Environment Texture

Start by selecting the Sun object and Environment Texture node. You can then synchronize them by enabling Sync Sun to Texture. Hovering any 3D Viewport will display the environment texture. Use the MMB to pan, scroll wheel to zoom, and Ctrl-MMB to set the exposure. Zoom and click the center of the Sun in the texture. After that, the Sun object will be locked to it.

You can now rotate both the texture and the light by using the Rotation slider.

Click the Sun in the environment texture in the 3D Viewport to lock it to the sun light object.

Translations

The add-on is currently available in English and French. If you’d like to help translate it to your language, please open an issue.

Authors

This add-on was originally written by Michael Martin with contributions by Aaron Carlisle, Brendon Murphy, Campbell Barton, Eduardo Schilling, Julian Eisel, n-Burn, and Stephen Leger. It uses the geo.py module by Maximilian Högner.

It is currently maintained by Damien Picard.

License

This add-on is licensed under the GPL license; either version 3 of the License, or (at your option) any later version.