360 degree panorama

Started by Doofus, December 23, 2006, 05:26:10 am

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Hannes

Here:
http://respam.terratalk.de/ReSPaM-Install.exe

you can find a program which does the job for you, if you just want to build panoramas out of BMPs (that's the only filetype that can be used), not HDRIs.

In your favorite 3D program set up your camera with a FOV of 90° and take six pictures: up, down, back, front, left and right, all exactly 90°.

The program is in german, so for those who don't know:
"Himmel" means sky, "Links" means left, "Rechts" means right, "Vorne" means forward, "Boden" means bottom and "Hinten" means back.
"Neu anfangen" means start from scratch and "Panorama machen" means make panorama.
"...drehen" means turn.
Believe me you won't see any seams. I tried it with the old Terragen-version and it worked perfect.
In the end you will have a large file with a strange ending. Just rename it to xxx.BMP and this will be your pano.
In an app like 3ds Max map this image spherically onto a sphere.

Hannes

Sorry, map it cylindrically!! :'(

U-Type

Quote from: MeltingIce on December 23, 2006, 02:15:25 pm
You could always render out 6 times in a cubic fashion with your FOV at 90, arrange the images in Photoshop into a Cross format, then use something like HDR Shop to convert the cross format to a longitudinal format.  It's what I did when I made skyboxes in Terragen 0.9.


In what way do i have to put them in the cross format?
Is it like                █
                        █ █ █ █
                           █

or a different arrangement?

helentr

December 30, 2006, 08:24:19 pm #48 Last Edit: December 30, 2006, 08:26:33 pm by helentr
Quote from: U-Type on December 30, 2006, 02:19:10 pm


In what way do i have to put them in the cross format?
Is it like                █
                        █ █ █ █
                           █

or a different arrangement?


The usual arrangement is:

     
         UP
     
LEFT FRONT RIGHT
     
       DOWN

       BACK (rotated 180 degrees)

Cube2cross does this automatically, if you give the right file names (and the images are square)

Helen

Doofus

December 30, 2006, 08:29:27 pm #49 Last Edit: December 31, 2006, 08:52:53 am by Doofus
I am now using a wrap around lens shader in mental ray which essentially uses cylindrical mapping to render out the final panorama. This replaces the built in max panorama exporter and gives far superior results both in the reduction of noticeable seams and in the retention of dynamic range data of the original OpenEXR TG2 files.

EDIT: And another thing. Added a spherify modifier to the octagony geometry, set at 100% which basically turns it into a perfect sphere and does all the image map distortion required. The lens effect on the Mental Ray camera just unwraps it and it looks even better.
Getting real close I think to being as good as if you had used a spherical camera right from TG2.

Just my opinion of course. :)
Rub a little funk on it baby :D

bib

I tried it with POV-Ray - a cube with 1024x1024 pixel textures (24 bpp, generated with TG 0.9) on each face, rendered a sphere map with 4000x4000 pixel and found no seams at all. The only noticable artefacts were introduced because of the strong distortion at the poles - usualy invisible color gradients become visible due to scaling some pixels up by a factor of 10 or so. But of course this vanishes by mapping the image onto a sphere again. A possible work around for hdr images would be scaling them up by a factor as huge as possible (thinking of memory limitations) and rendering the sphere map at the desired resolution. Rescaling the images will soften the gradients and make them less visible in the sphere map. But this works only for hdr images, because 256 values per channel are not enough to smoothen the gradients over larger areas. And for scenes with architectural features scaling may introduce bluriness.

p.s.

And there will be no noticable difference when viewing the image on the screen due to the limitation of the display or video adapter.

Doofus

Can I get a look at the resulting panorama please bib.
I am happy with the way I am going, but if there is truly an easier way that works then I will take it. I'm not doing this to be obtuse, I genuinely find that the differences in the top and bottom images of a cube and the four side images with regards to how much they need to be distorted to make a panorama always shows up come animated rendering.
Also I have never used POV-Ray. I am going looking for a download now, but if you could send me your POV-Ray file too I would be very grateful. Would save me some time figuring out how to work it properly.
Cheers.
Rub a little funk on it baby :D

bib

That's not that easy ... I've got only a 56k modem and the file is about 45 MB. Compressing it definitly generates seams at the borders. Just get POV-Ray and use the file I already posted.
And I was able to produce some seams with POV-Ray. I thought about scaling the images a view posts ago. I tried that with POV-Ray - adding "interpolate 2" to each image_map will cause POV-Ray to use bilinear interpolation and introduce seams at each edge. I think I know why this happens in POV-Ray, but I am not sure if this applys to other programs, too. Just try it with and without interpolation. I would like to hear about your result and would like to know, if the seams with interpolation are similar to the seams from other programs.

jo

Hi,

Quote from: Sethren on December 28, 2006, 05:43:58 pm
Goodness i really hope that Matt implements render options like Vue 6 infinite has like 360 Spherical Panoramic rendering. Right now i am doing a project for a company that i work for that requires the creation of HDRI Lighting using cubic maps and or light probes but sense i can not afford Vue 6 Infinite nor do i have the time or computing power to render out 6 individual Terragen 2 renders


I would think that rendering a 360 degree spherical panorama would involve rendering more or less as much as it would to render 6 individual faces of a cube, and therefore take a similar amount of time.

Regards,

Jo


JimB

Quote from: jo on January 11, 2007, 06:15:52 pm
I would think that rendering a 360 degree spherical panorama would involve rendering more or less as much as it would to render 6 individual faces of a cube, and therefore take a similar amount of time.

Probably even longer to render a single frame than six, given the way most decent renderers optimise. Think about how it's been commented on the differences in cropped renders and full frame renders. No matter what, 360 degrees of coverage is 360 degrees of coverage, whether you split into six or just one.
Some bits and bobs
The Galileo Fallacy, 'Argumentum ad Galileus':
"They laughed at Galileo. They're laughing at me. Therefore I am the next Galileo."

Nope. Galileo was right for the simpler reason that he was right.

_Sin

Quote from: jo on January 11, 2007, 06:15:52 pm
Hi,

I would think that rendering a 360 degree spherical panorama would involve rendering more or less as much as it would to render 6 individual faces of a cube, and therefore take a similar amount of time.

Regards,

Jo



Sorry to dig up a slightly older thread, but I'm struggling with this at the moment. I'm trying to get Terragen to render faces for an environment cube, and while it's easy enough to set up the camera and get 6 images with 90 degree FOV, they don't actually match correctly. The geometry seems fine, the problem is that the colour doesn't match across the seams of the image. Either some part of the rendering is view dependent, or else there is some tone-mapping or other image adjustment happening behind the scenes. This is clearly visible in output images in both EXR and BMP formats. As I actually want a cube, I really don't want to have to take many more images and play with stitching software - the best possible result should come from directly rendering 6 images. This worked fine with the older Terragen...

Anyone else seen this and/or found a way around it?

Volker Harun

Hi _Sin,
I am just guessing due to other threads. This could be a GI-matter. Maybe you should use instead of GI the lighting clips supplied by Oshyan (Shared Files, the Topmost Thread).

Regards,
Volker Harun

_Sin

Quote from: Volker Harun on February 15, 2007, 08:04:31 am
Hi _Sin,
I am just guessing due to other threads. This could be a GI-matter. Maybe you should use instead of GI the lighting clips supplied by Oshyan (Shared Files, the Topmost Thread).

Regards,
Volker Harun


Yup, that seems to be the problem! My bad for not checking other threads more thoroughly - my initial search didn't turn anything up, but I see the other postings about this now...

Thanks!

bigben

I hadn't seen this thread before.. but there seemed to be a lot of confusion and overcomplication of some of the stitching issues.  My background is in photography and creating spherical panoramas, so I've made a few in my time  ;). http://www.communitywalk.com/map/109

The simplest method (mentioned by a couple of people already), using completely free software is to use CubeToCross and the free version of HDRShop. Creating 6 cube faces of 90° fov means that there is no overlap of the images so there should be no blending of images set in any application. Blending is only required with overlapping photographs. Even if your rendererd images overlapped there should still be no need for blending.

Here is a test equirectangular (spherical) HDR image I produced in 2004 with TG0.9 using this software: http://www.path.unimelb.edu.au/~bernardk/demo/sunset8c_025.hdr (2.6Mb)

I've also used Panorama Tools to stitch animations on the fly for non-HDR images. Here's a small movie from TG0.9 using a cylindrical lens with a 180° fov. http://www.path.unimelb.edu.au/~bernardk/demo/pano_test.avi (802kb)

The only other potential problem I can see people having is if they rotate the camera in the preview window rather than editing the camera's settings. This will change the position of the camera and cause parallax errors. I haven't created a spherical panorama in TG2 yet, but I certainly will be in the near future.

Allegro

Sorry if I missed it, but is there a free program I can use to convert a cross-type .exr image into a longitudinal one?

I'm trying to make a short for school/festivals and my budget is toast now, so I can't afford a commercial license even though that's kind of what I need.  It'd be really nice to be able to get my tg2 renders into maya to use for a hdr light dome.  Note:  I'm on windows, and don't know how to do anything in linux