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Richard Hebert
07-14-2012, 09:27 AM
Hi Everyone,

Anyone know what kind of mapping Image World likes to have? Rectangular 'spherical maps' aren't being displayed properly and I've tried other mapping formats and everything stretches to a point on one side of the image.

RebelHill
07-14-2012, 09:40 AM
Angular map is what you're after. HDRshop (the free basic version) will do the co-ord conversion if you have nothing else.

It would be nice if image world let you choose the mapping type. Ofc, u can also use texture environment, which'll let you use spherical, cubic, etc.

Richard Hebert
07-14-2012, 09:48 AM
The light probe image in the screenshots is an angular mapping type. Do you know what might be causing this? Textured environment is what I used until now but it doesn't use all of the extra lighting data contained in the hdr file.

RebelHill
07-14-2012, 10:17 AM
YEs, lightprobe, aka angular map...

Now Im presuming that the image has been captured using a mirrorball, correct? If so, this its an artefact from the capture (I get this all the time).

Basically, the very edges of the mirrorball (and ofc the tiny spot occulded by the ball itself), will be highly distorted, or rather "low-res" as the very edges reflect most of the "behind", but in a very small "slice" of the ball.

The remedy is to shoot your mirrorball images twice, at least 90deg apart. You then convert each to lat/long map, so as you can clone the good bits of one over the bad bits of another, and then convert back to whatever map type you want.

As I say, I get this a lot, but generally dont care, as I always shoot my mirrorball images with the behind portion being behind where my virtual camera will be... so out of shot (the lighting it gives, though distorted image wise is usually close enough). The only time I go to the extra effort, is when Im going to be needing to turn the virtual cam right around, or ofc, when Im needing the image for reflections.

So yeah... its the live shoot of the ball basically. Take your map, or your original mirrorball image, and convert to lat/long, and you'll more easily see why, and where the problem is present.

And really... does TE not use the full HDR stuff... never noticed that, but ofc, almost never use it. I have used it though with procedural type things, DPs sunsky primarily, and it def gets a high range from that... maybe its an image thing, but procedural things are OK... worth asking around, checking out whats going on there methinks.

Richard Hebert
07-14-2012, 10:23 AM
Thanks for the info. That is very helpful.

Richard

Richard Hebert
07-14-2012, 12:21 PM
Apparently, HDRshop no longer has a free version. If this is inaccurate, could you post a link to that version? Thanks again for the insight. It would be nice if ImageProbe had various format options like Textured Environment. Does Textured Environment use the additional data from an HDRI like Image World?

Richard

Richard Hebert
07-14-2012, 08:41 PM
There is a way to convert rectangular HDR's into spherical ImageProbe HDR's within LightWave. This is quickly becoming a huge time saver and I'm converting all my rectangular files starting tomorrow. For anyone interested... you can import the rectangular format into the Textured Image backdrop option and then change the render camera to the Advanced Camera (I routinely use the Real Lens Camera and forgot there was any other camera in the menu). Change the Advanced Camera's 'Horizontal FoV' setting to 'Spherical' from the drop down menu and then change the default value (45.24 degrees) to 360 degrees. Close the palette and adjust the render size to anything square 1000x1000 2000x2000 etc. It all depends on how much detail you need to retain in the image. When it's rendered save the image file as a Radiance.hdr file from the formats listed. The resulting spherical image will import into Image World properly mapped (as far as I can tell) and still retain it's HDR data. Rebel Hill inspired me to do research that led me to this solution for this particular problem... so... thanks again to him and keep inspiring us.

Richard

Richard Hebert
07-16-2012, 08:31 PM
After doing a couple of test renders comparing Image World and Textured Environment I saw no noticeable differences in the lighting. Is it safe to presume that these two backdrops use the full range of the .hdr format to light the scene?

Richard

rcallicotte
07-16-2012, 09:23 PM
Great thread! Can't answer your question, but I am not sure I would know all the nuances to answer. Sounds like it might be close from what you're saying.

I want to try this.

Richard Hebert
07-16-2012, 09:30 PM
I never used image world due to the fact that the image coordinates were all wonky and I really don't have a way to convert them into something useable at least for me. This got me to thinking about the possible differences in the two. I really like having the coordinate options of Textured Environment and if all the data is accessed then I'll use it until I can buy something like HDRshop for conversions. Glad somebody can get some use out of this besides me. Thanks for the response and if you hear anything different go ahead and post it!

Richard

Exception
07-17-2012, 12:39 PM
I'm pretty sure Lw uses HDr information anywhere you use an HDR image, including Textured Environment.
Whether that's true or not, I am 100% sure textured environment uses as much of HDR info as Image World does. Image World, as far as I see it, is just there because Textured Environment doesn't support Image Probe maps, so they added that to enable the use of those images...

RebelHill
07-17-2012, 01:09 PM
I thought TE must use HDR info too.

Anywhichway, glad your explorations have helped sort things out for you.

Richard Hebert
07-17-2012, 04:17 PM
Thanks Rebel and Exception (Not their real names I'm sure). Looking forward to purchasing RHiggit in the next few months hinging on new job start date!

Richard

dwburman
07-17-2012, 09:22 PM
As RH said, you're getting the starburst because you're looking at the backside of the image probe. If you rotate your image probe 180 on it's heading in the Image World settings, you should be good to go.

Richard Hebert
07-17-2012, 09:38 PM
That was my thought at first but it's the coordinate system that isn't compliant. I tried just rotating the heading and that's not going to eliminate that awful stretch but it will place it in an inconspicuous spot if you're only needing it for 180 deg. Rectangular maps can be converted into a decent image probe map (not flawless but the coordinates do line up a lot better without the starburst effect) with a render from the advanced camera. With that being said, since Textured Environment is producing similar renders (at least it appears that way) then that seems to be the best option until somebody can shed more light on any differences between those two. Thanks for all the responses, maybe something from Sensei?...

Richard

Lightwolf
07-17-2012, 10:10 PM
I'm pretty sure Lw uses HDr information anywhere you use an HDR image, including Textured Environment.
Whether that's true or not, I am 100% sure textured environment uses as much of HDR info as Image World does. Image World, as far as I see it, is just there because Textured Environment doesn't support Image Probe maps, so they added that to enable the use of those images...
What he said... :)

With that being said, since Textured Environment is producing similar renders (at least it appears that way) then that seems to be the best option until somebody can shed more light on any differences between those two.
They essentially contain the same information. However, rectangular maps make better use of the available pixels (no black, unused areas) and the pixel/area distribution per sampled angle is a little better.
Ideally, a chunk (as in: surface area) of the surrounding sphere surface should be covered using the same amount of pixels regardless of the viewing angle, in practice this isn't the case (this is similar to printing map of the globe on paper while maintaining correct areas).
Lat/Long does make sense if you have photographed HDRI environments (sphere balls), since these are close enough.

Cheers,
Mike

Sensei
07-18-2012, 12:40 AM
Anyone know what kind of mapping Image World likes to have? Rectangular 'spherical maps' aren't being displayed properly and I've tried other mapping formats and everything stretches to a point on one side of the image.

Use Textured Environment this way:

http://forums.newtek.com/attachment.php?attachmentid=105602&stc=1&d=1342593347

http://forums.newtek.com/attachment.php?attachmentid=105603&stc=1&d=1342593347

It's picture from
http://www.lizardlounge.com/html/tutorials/c4d/sphericalMap/images/hirez_finished_map.jpg

Sensei
07-18-2012, 12:42 AM
Spherical mapping has every X mapped directly to H angle from 0 to 360 degree.
And Y = 0 is mapped to top, Y= HEIGHT is mapped to bottom of camera view. So P angle is from 0 to 180.

You can render such map using TrueArt's Environment Baking Camera.

http://forums.newtek.com/attachment.php?attachmentid=105604&stc=1&d=1342594102