iplusone
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Houdini Fisheye lens for Hemispherical Projection June 16, 2010, 11:26 a.m.
(copied post from alternate forum)
First off, thanks for the replies! I ended up approaching this from a different angle. Unfortunately it requires Nuke to work. Basically I wound up just rendering out a six-pack through Houdini's built in cube-map generator, then plugging each of the resultant image planes into Nuke's Spherical Transform Node and transforming from cube-map to 180 degree fisheye.
We did some tests comparing the Mental Ray shaders distortion to what Nuke was generating and discovered it was a 100% match (although we had to use mirror nodes to get the coordinate space to match, although this step could be handled during the icp processing). The beauty of this method is that it requires no raytracing. The drawback is having 6x the number of images (although each cubemap image can be 1/3 the final resolution size, which may help with memory issues in certain situations) for each frame, and needing Nuke. Nevertheless, it works well if you're lucky enough to have access to both software packages.
One thing I'd like to look into over the summer is writing a python script to assemble and distort the six-pack output automagically, without any help from Nuke. I'll post here and over on Odforce regarding the progress and share the code for feedback and testing as I go. Thanks again.
example files are available for download here
http//www.peterstratton.com/DLsOnTheDL/cubemap2fisheye.zip
First off, thanks for the replies! I ended up approaching this from a different angle. Unfortunately it requires Nuke to work. Basically I wound up just rendering out a six-pack through Houdini's built in cube-map generator, then plugging each of the resultant image planes into Nuke's Spherical Transform Node and transforming from cube-map to 180 degree fisheye.
We did some tests comparing the Mental Ray shaders distortion to what Nuke was generating and discovered it was a 100% match (although we had to use mirror nodes to get the coordinate space to match, although this step could be handled during the icp processing). The beauty of this method is that it requires no raytracing. The drawback is having 6x the number of images (although each cubemap image can be 1/3 the final resolution size, which may help with memory issues in certain situations) for each frame, and needing Nuke. Nevertheless, it works well if you're lucky enough to have access to both software packages.
One thing I'd like to look into over the summer is writing a python script to assemble and distort the six-pack output automagically, without any help from Nuke. I'll post here and over on Odforce regarding the progress and share the code for feedback and testing as I go. Thanks again.
example files are available for download here
http//www.peterstratton.com/DLsOnTheDL/cubemap2fisheye.zip
Houdini Fisheye lens for Hemispherical Projection April 2, 2010, 2:41 a.m.
Hey everyone,
So, I'm working on a planetarium dome projection project and i'd really like to use Houdini. There is a Mental Ray lens shader that can emulate a 180degree fisheye lens. I'm wondering if there is a way to do this in Houdini. There is a lens_curvature parameter that can be applied to cameras, but i've not been able to get the proper effect. I suspect it's the relationship between the focal length, aperture, and lens_curvature that will yield the proper result, but i'm unsure how to set it all up. Have any of you worked on a similar project or have an idea about how to approach this? Any examples or tips would be greatly appreciated. Thanks!
So, I'm working on a planetarium dome projection project and i'd really like to use Houdini. There is a Mental Ray lens shader that can emulate a 180degree fisheye lens. I'm wondering if there is a way to do this in Houdini. There is a lens_curvature parameter that can be applied to cameras, but i've not been able to get the proper effect. I suspect it's the relationship between the focal length, aperture, and lens_curvature that will yield the proper result, but i'm unsure how to set it all up. Have any of you worked on a similar project or have an idea about how to approach this? Any examples or tips would be greatly appreciated. Thanks!
world space error? Nov. 22, 2009, 11:17 p.m.
thanks Tamte, would that also affect the ST space?