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moth0027
09-08-2005, 05:13 AM
Hello All,

I've never really used Sky Tracer 2 but I decided to try my hand at it to make a lightprobe image for Image World.

I successfully made a sky I was happy with but when I added it to Image World it looked fine from the front however the back of the image was really pinched.

I also tried using the sphere from Sky Tracer 2 on a sky dome but still got strange pinched areas.

Any ideas? Thanks in advance.

Mebek
09-08-2005, 11:03 AM
This happens with all probe images, as far as I know. It has to do with how probe images are polar-mapped into the world.

moth0027
09-09-2005, 02:48 AM
Hey Mebek,

Thanks for the reply.

I suppose the best way to do this is with a cylinder wrapped around the scene since it's an interior shot and will not be seeing the hole in the sky above.

Thanks again

toby
09-09-2005, 02:29 PM
Lightwave can't make a light probe image, as far as I know. A light probe image is... well imagine photographing a chrome sphere from 2 opposite sides, and merging the 2 images together. This is the only type of image that Image World will map correctly.

Captain Obvious
09-09-2005, 03:17 PM
I recomend baking to a spherical map instead. That way you get more or less the same pixel intensity all over the map. Sure, you can't use the ImageWorld backdrop to apply the map to a scene, but it's not that big a deal, really. Just use the Textured Environment backdrop instead.

BazC
09-09-2005, 03:17 PM
"I suppose the best way to do this is with a cylinder wrapped around the scene since it's an interior shot and will not be seeing the hole in the sky above. "

No, use a sphere, use spherical mapping and y texture axis, you'll still get pinching but they'll be straight up and down. You won't be pointing the camera in those directions very often!

It would be nice to have some different mapping options for image world, it's pretty limited the way it is now! - Baz

toby
09-09-2005, 10:04 PM
uhh.. the only point of Image World is light probe images... otherwise it's the same thing... any other mapping can be done with textured environment -

gerardstrada
09-09-2005, 11:34 PM
Lightwave can't make a light probe image, as far as I know. A light probe image is... well imagine photographing a chrome sphere from 2 opposite sides, and merging the 2 images together. This is the only type of image that Image World will map correctly.


I agree, if you wanted to make a lightprobe in LW you need 2 takes at 90° of separation, save them as HDR or some other dynamic_range format and assemble them in HDRShop. However I also think that it's easier to make a latitude/longitude format (to use it in Texture Environmet/spherical_map). You can do it with JJ_Special_Projection by Juan José Gonzáles (free), Enviro by WorleyLabs (commercial), Microwave (baking reflections) by Evasion3D, or with RefGen by Ekki Halkka (shareware), this last allows you to use any shader or image/pixel filter.



Gerardo

BazC
09-10-2005, 03:32 AM
uhh.. the only point of Image World is light probe images... otherwise it's the same thing... any other mapping can be done with textured environment -


DOH! My apologies, I'm new to lightwave and wasn't aware of the textured environment option. I must learn to keep my mouth shut until I know what I'm talking about lol!

It seems an odd way of doing things though, why not add the light probe option to textured environment? Much as I like the feel of lightwave these endless lists of plugins make it a little disjointed, especially as many repeat functions of others. I hope this is one area that is being refined! - Baz

Red_Oddity
09-10-2005, 06:32 AM
Image World uses Angular maps, not Sperical maps, big difference...

Pictures tell more than words in trying to explain this thus i refer you to page 6 of this Siggraph paper : http://www.debevec.org/IBL2003/debevec-IBL2003-Main-slides.pdf