17.2. Panoramic renderings

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), 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 17-5. Panorama button.

Figure 17-6 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. 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).

Figure 17-6. Panorama test set up.

To obtain something similar without the Panorama option, the only way is to decrease the camera focal length. For example Figure 17-9 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.

Figure 17-7. Non-panoramic rendering.

Figure 17-8. Panoramic rendering.

Figure 17-9. Fish-eye rendering.

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. This is grossly distorted, since a 16.0 lens is a wide angle lens, and distorts at the edges.

Figure 17-10. Full 360 panorama with 16.0 lenses.

To have undistorted views the focal length should be around 35.0. Figure 17-11 shows the result for a panorama with 8 Xparts and a camera with a 38.5 lens, corresponding to a 45 viewing angle.

Figure 17-11. Full 360 panorama with 38.5 lenses.

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 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 SizeXSizeY or you are willing to make some tests.