WARPING FAQ

Jump to Support FAQ

• What is warping?
• Why would you use a mirror?
• What is pre-warped content?
• Do I need special software to play pre-warped content?
• Are all of ePlanetarium’s videos available in pre-warped format?
• What software allows fisheye videos to be shown on a mirror system?
• What software allows flatscreen videos to be shown on a mirror system?
• What software allows 360VR content to be shown on a mirror system?
• Which star programs work with a mirror?
• What is a warping mesh?
• Is the dome projection surface completely filled by the video?
• Is the back out of focus or distorted?
• Can I warp my own video in real time?
• Can I pre-warp my own video?
• My dome is very large or very small. How can I make the mesh fit better?
• How long does it take to set up the mirrors?

 

 

What is warping?

Warping is a process where the original fulldome image is distorted so that when it bounces off a mirror, it can fill (or nearly fill) a spherical dome. Special warping meshes can also be used for odd-shaped spaces like ellipsoid or rectangular rooms. Warping images and videos for domes was invented by Paul Bourke, who has several web pages on techniques and software.

WARPED format

FISHEYE format

This is an example of the warped video format. Video is projected onto a spherical mirror located in the rear of the dome which allows use of the whole dome for seating. The image of a mirror system has some distortion on the far edges, but this is the portion projected behind the seated viewers. All of the primary action (shaded in RED) of a typical full-dome video is located where the mirror system looks best (highlighted in GREEN).

This is an example of the fisheye video format. A fisheye lens is used to project video up from the center of the dome. This means seating must be spread around the dome in a circle. The image of a fisheye system can have distortion and chromatic aberration near the horizon line in all directions. A fisheye system looks best directly overhead (highlighted in GREEN). Only a portion of the primary action (shaded in RED) of a typical full-dome video is in this area.

 

Why would you use a mirror?

Save money and allow easier replacement of pieces (projector, etc available locally) no chromatic aberration. Below is an example image (left) and an actual image from a fisheye dome (right). The highest-quality fisheye lenses are very expensive.

Chromatic aberration of star image

Chromatic aberration example from inside dome with fisheye projection

 

What is pre-warped content?

Pre-warped content is a video that has already been distorted so that it works well when bounced off a mirror. This can be higher quality and higher frame rate than if done in real time (depending on your software and your computer). It also allows us to be able to stream rentals of pre-warped content using fulldomeondemand.com, and for users to be able to use simple video players in a dome.

 

Do I need special software to play pre-warped content?

No, you can play with any video player. But MediaShow allows more control over the playback, allows a sequence of shows, and allows subtitles.

 

Are all of ePlanetarium’s videos available in pre-warped format?

Every show we sell is available in pre-warped or fisheye format. That includes all of the ePlanetarium-developed shows plus all of the HMNS shows and many shows from other producers including Evans and Sutherland, Mirage 3D, Clark, etc.

 

What software allows fisheye videos to be shown on a mirror system?

Fishtank, VLC Warper (Mac or Windows); Fishwarp, QuickTime Movie Player (Mac only); Digistar

 

What software allows flatscreen videos to be shown on a mirror system?

MediaShow, Fishtank, Digistar

 

What software allows 360VR content to be shown on a mirror system?

Fishtank, Digistar

 

Which star programs work with a mirror?

Stellarium, WorldWide Telescope (Windows or Mac on a browser), Digistar

 

What is a warping mesh?

A warping mesh is the grid transform to map the original fisheye image into the proper distortion so that, when the image is bounced off a mirror, it fills the dome correctly. These meshes also include a reduction in intensity towards the back to make the brightness of the image more uniform. Warping meshes can be customized for many projection geometries.

 

Is the dome projection surface completely filled by the video?

No, the very back 5-10% is a shadow zone. But for theater-style seating, the viewers are not looking that direction. Their peripheral vision only covers about half of the dome.

 

Is the back out of focus or distorted?

Depending on how accurately the mesh is created for the particular dome/mirror combination (including the size and placement of the mirror in the dome), the back can be perfectly in focus with no distortion. However, if one uses a “standard” pre-warped video, the back might be slightly distorted or out of focus depending on your dome geometry. However, for most applications the prime viewing area (including the peripheral vision area) is perfectly acceptable even with the standard mesh.

 

Can I warp my own video in real time?

Yes there is software that allows this like Fishtank, VLC Warper (Mac or Windows); Fishwarp, and Digistar.

 

Can I pre-warp my own video?

Yes but the process is tedious and detailed. This is why we pre-warp our shows for you. We can warp to custom grids if necessary, for a fee.

 

My dome is very large or very small. How can I make the mesh fit better?

1. Create a custom mesh using MeshMapper, or pay ePlanetarium to create one for you.
2. Use Digistar and distort the mesh.

Once you have a custom mesh you can use video players like VLC Warper or WorldWide Telescope.

 

How long does it take to set up the mirrors?

The first time takes about 15-20 minutes to get the best possible view. After that, the lifting arm “remembers” and you can mark the metal ruler in the N3 to remember the ideal position. Future setups take less than a minute.