Render spherical barrel distortion with fisheye projection.
- [Instructor] Wide-angle lenses on real-world cameras exhibit a specific type of image distortion called barrel distortion, or spherical distortion. And it's different from the look of a perspective projection that we would see in a standard CGI camera. But the Arnold camera attributes allow us to introduce fisheye lens, or barrel distortion, into renderings. Let's do a render of the camera view with no fisheye lens distortion.
Go to the menus and choose Arnold, Render. When that rendering has completed, store it as a snapshot in memory by clicking the camera icon in the lower right of the Arnold render view. Let's introduce the fisheye distortion. Select the camera in any view port, and open the attribute editor with Control + A. At the top are the familiar camera attributes. The angle of view for the camera is currently 90 degrees.
And we've got the film back settings that allow it to do things like offset the image horizontally and vertically. Scroll down a bit, and open up the Arnold section. And at the very top is the camera type. And as long as camera type is set to perspective, then the standard Maya attributes will work as expected. But once we change the camera type to something else, then field of view and film offset will no longer operate.
So let's choose the camera type, set it to fisheye. And in the Arnold render view, we see a fisheye lens effect. Well, we got some black edges here. There's a nice option over here called auto-crop, which will automatically remove those black edges. So I just turn on auto-crop, and now we've got a nice fisheye effect, but the framing is different from our snapshot. We can go over and click on the snapshot and see that it's zoomed farther out.
Go back to the in-progress rendering, click on the little eye icon, and we just need to increase the field of view in the fisheye attributes to better match the framing of the other image. Set field of view to 105. Once that rendering has completed, we can make another snapshot and do a more accurate comparison. Here's the version without the fisheye distortion, and here's the version with the fisheye lens distortion.
And here's a full-screen rendering before and after changing the Arnold camera type. And that's how to apply fisheye lens, or spherical or barrel distortion, using Arnold.
- Arnold rendering concepts
- Lighting with Maya and Arnold lights
- Controlling exposure
- Filtering light with Gobo
- Light attenuation with Decay
- Image-based lighting with Skydome
- Exterior daylight with Physical Sky
- Arnold Standard Surface material attributes
- Mapping material attributes
- Rendering refractions
- Mesh subdivision and displacement at render time
- Shading effects such as ambient occlusion and vertex color
- Camera effects such as fisheye and depth of field
- Animation image sequence rendering