A lot has gone on over the last couple of years with WWT in the planetarium environment. WWT has long supported Fisheye and warped mirror dome full dome projection right out of the box, and multi-channel projection for larger domes, but multi-channel systems required either and expensive blending system like Global Immersion, or a time consuming and painful process of manual alignment with Projection Designer. At the American Astronomical Society (AAS) meeting in Seattle we released a new build of WorldWide Telescope that has a new feature that allows painless computer assisted alignment build right into WWT. The new system is so easy that once you setup your projectors to ensure a good overlap of the image surface you can be fully aligned and blended in a few hours. And that include they time to create physical masks to reduce the light leak overlaps during complete dark screens.

The net result is that using this system the University of Washington was able to convert their analog star ball planetarium to a 6 channel WWT based full dome digital system for under 40k including all the computer equipment, construction labor, projectors, cables, etc. The system was 6 HD projectors for a net 9 Mega-pixel (between 3k-4k dome master resolution).

The alignment UI is the real sweet part of this. For each overlap of two projectors there is an edge. You just add between 6-12 points per edge. The "left" and "right" monitors for each edge will show a red and green X respectively and all you do is use the right mouse button to drag the green X and the left for the red X, when you get them aligned in the overlap area, just move to the next one. It is very simple and predictable. When this process is done, you add a handful of points at the spring line, the dome cap and the cardinal directions. Maybe a few more in know locations like 45 degrees up the North meridian. When you are done with that, you push a button and WWT computed the best fit for all the camera parameters and then generates warp maps to aligned everything up to pixel-perfect alignment. Even after the first fitting step, WWT will warp out any residual error that the parameter fit could not account for. After that step is done you play connect the dots to draw a polygon for your blend map. You control how you want the shape to look. Since it all happens on the dome in real-time you see exactly where the seams will go. You can then select how much software feathering you want in the blend to get the best transition. Once you color match your projectors, you can make hardware masks that will mask out the unused portions of the overlap to reduce the overlap pattern when complete or near complete blackness is displayed. The results are spectacular. You have never seen resolution like this.

We may also add support for 3rd party system that would allow (at extra cost to the end user) fully automated camera based alginment and blending, but the time saving of our new alignment system over the previous Projection Designer method are so great that the marginal difference to fully automatic alignment will only be worth it when re-alignment needs to be performed often and quickly, and where clear view of the full dome can be had from the center sweet spot.

Driving from a XBOX 360 wireless remove is also very cool. You can switch between sky, panorama, Earth, Planet and 3d Solar system modes, speed and slow time, move from planet to planet, zoom in/out and rotate and turn on-and off options like constellation lines and grids all from the controller.

There are also a bunch of new features and fine tunning to make WWT run better in a dedicated dome environment.

Also don't forget WWTRemote. WWT Remote remote controls your dome cluster to allow you to wake up , start WWT , close WWT, run scripts, or shutdown all your machines with one click on the master. You will need Wake-on-Lan on your motherboard for the startup function, but the rest will run on any machine. WWTRemote is available on the SDK downloads page.

We are working on improving the WWT Tour authoring for dedicated full dome authoring. We have an Alpha of this functionality now, that also supports up to 4K dome master output as discrete frames to aid in production of full dome video shows.

E-mail me if you are interested in full dome production or multi-channel alignment and blend.  wwtpage at Microsoft dot com (remember to turn the at into @ and the dot into .)


Originally posted by Jonathan Fay. Migrated to new blog location by derickc.