Relevant to Blender v2.31
To obtain nice panoramic renderings, up to a full 360° view of the horizon, Blender provides an automatic procedure.
If the Xparts
is greater than 1 and the
Pano
button of the Render
Panel
is pressed (Figure 17.5, “Panorama button.”),
then the rendered image is created to be Xparts
times
SizeX
wide
and SizeY
high, rendering each part by rotating the camera
as far as necessary to obtain seamless images.
Figure 17.6, “Panorama test set up.” shows a test set up
with 12 spheres surrounding a camera. By leaving the camera
as it is, you obtain the rendering shown in Figure 17.7, “Non-panoramic rendering.”.
By setting Xparts
to 3 and selecting Pano
the result is
an image three times wider showing one more full camera shot
to the right and one full to the left (Figure 17.8, “Panoramic rendering.”).
To obtain something similar without the Panorama option, the only way is to decrease the camera focal length. For example Figure 17.9, “Fish-eye rendering.” shows a comparable view, obtained with a 7.0 focal length, equivalent to a very wide angle, or fish-eye, lens. Distortion is very evident.
To obtain a full 360° view some tweaking is necessary. It is known that a focal
length of 16.0 corresponds to a viewing angle of 90°. Hence a panoramic
render with 4 Xparts
and a camera with a 16.0 lens yields a full 360° view,
as that shown in Figure 17.10, “Full 360° panorama with 16.0 lenses.”. This is grossly
distorted, since a 16.0 lens is a wide angle lens, and distorts at the edges.
To have undistorted views the focal length should be around 35.0.
Figure 17.11, “Full 360° panorama with 38.5 lenses.” shows the result for a panorama
with 8 Xparts
and a camera with a 38.5 lens, corresponding to a 45°
viewing angle.
The image is much less distorted, but special attention must be given to proportion.
The original image was 320x256 pixels. The panorama in Figure 17.10, “Full 360° panorama with 16.0 lenses.”
is 4 x 320 wide. To keep this new panorama the same width, the SizeX
of the image must be set to 160 so that 8 x 160 = 4 x 320.
But the camera viewing angle width occurs for the largest
dimension, so that, if SizeX
is kept to 256 the image spans 45° vertically
but less than that horizontally, so that the final result is not
a 360° panorama unless SizeX
≥ SizeY
or you are willing to make some tests.