Hi,

I've got a job where I'm creating some animation for an immersive dome. It's a little over a half sphere. The arc is 210º (or 105º from the ground to the middle top of the dome).

I'm wondering can I use the VR camera to map my animation directly to this?

You can alter the Vertical FOV in the VR camera but it seems to trim in from the top and bottom simultaneously. I just want to trim off the bottom. (I'm probably using the wrong terminology here!).

In Cinema 4D it seems fairly easy (see screen cap) but ideally I'll stay just in Houdini. Is there a way of doing this?

Thanks

It'll be renderer specific.

Mantra lets you create your own lens shaders in vex, myself and Matt Ebb have some examples + notes:

https://www.tokeru.com/cgwiki/?title=HoudiniOculusWip [www.tokeru.com]
http://mattebb.com/blog/weblog/houdini-fisheye-camera/ [mattebb.com]

You'd need to read up on the maths behind a hemispherical camera to do the right thing, Paul Bourke is the main person who has all the info and worked this out years ago:

http://paulbourke.net/stereographics/ [paulbourke.net]

Any other renderer, you'll need to talk to those render devs directly. Last I checked Karma didn't have user defined lens shaders, but that was a while ago, hopefully things have changed.

The other more brute force way is to just render a pure 360 latlong, and distort/convert/crop in comp, but that could be a pretty wasteful and heavy render.

Thanks as ever Matt. Hmmm I think reading up on lens and shader mathematics maybe beyond me. But I'll give it a go!

I managed to find a way not to do maths
https://www.orbolt.com/asset/nhat::DomeMaster