Tilecam is a Blender add-on that makes it easy to render seamlessly repeatable images. To see Tilecam in action, check out this tutorial video.
Here's a repeatable image rendered using tilecam...
...and here's the result of repeating the image above.
Download the latest version from the releases page. Make sure you download the file called tilecam.py
attached to the release.
Open the preferences window by selecting Preferences from the Edit menu
Select the Add-ons tab and press the Install button
Select the file you downloaded in the first step and press Install Add-on from file
Locate Tilecam in the add-on list and enable it by pressing the checkbox.
The Tilecam panel can be found in the properties editor under the camera tab (which is only visible when a camera is selected).
Given identical objects repeated along the Blender grid floor, one unit apart, tilecam sets up the camera so that the viewport can be seamlessly repeated. For example, this grid of Suzanne meshes...
... looks like this seen through a camera aligned using Tilecam. The viewport can be seamlessly repeated.
If you're using Blender 2.8 or later, it's highly recommended to create a collection containing the geometry you want to repeat and then repeat it using collection instances.
An aligned camera can be moved freely as long as it's not rotated.
Tilecam uses the current horizontal resolution when aligning the camera. If you want to change resolution, just change the horizontal resolution and press Apply again.
The horizontal period determines the number of grid squares in the horizontal direction per tile.
The vertical period determines the number of grid squares in the vertical direction per tile.
The elevation is the angle between the line of sight and the xy plane. A 90 degree elevation corresponds to a top down view.
The repetition count controls the number of tiles in the final image.
Checking the isometric box overrides the elevation and horizontal and vertical periods to produce an isometric image, i.e an image where the contour of a cube is a regular hexagon.
Use the Apply button to align the currently selected camera.
The following examples, using equally spaced cubic boxes, illustrate how the parameters affect the final image.
Horizontal period: 1, Vertical period: 1, Elevation: 24°, Repetition count: 2
Horizontal period: 3, Vertical period: 1, Elevation: 30°, Repetition count: 1
Horizontal period: 2, Vertical period: 1, Elevation: 80°, Repetition count: 1
Repetition count: 2, isometric view