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Cube Map Software
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* August 30, 2010, 03:12:52 PM
Does anybody know of any good free cube map creation programs, or photoshop psp tutorials for similar, also any programs to convert between projections, fixed cross, panorama, cube map, cylindrical, spherical etc.

Anything to get me started would be a great help.

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September 07, 2010, 03:26:06 PM
#1
Michael, are you looking to create high-dynamic range maps or standard low-dynamic range maps?

There are many good programs out there to help you assemble an HDR or LDR map. Not many are free, but most have a trial version available. If you have Photoshop CS3 Extended or newer you can work with 32-bit HDR right in Photoshop. Flaming Pear offers a Photoshop plugin called Flexify that allows you output just about any projection you could need. It isn't free but works very well.

Unfortunately, hardly any of the HDR programs out there include projection transformation functionality. HDR Shop is pretty much the grandfather of HDR programs but allows you to assemble and transform projections. Version 1 is still a free download, and version 2 is available for purchase.

There is a free program called Picturenaut (great website) that is fantastic for creating and editing HDR images, but it doesn't currently handle transformations. It can also use the available HDR Shop plugins. The host website offers a very helpful list of the various programs out there for HDR workflow
.
Are you planning to create your own "real-world" maps like the ones included with TurboCAD?

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BradE [ dean3Design ]
Core i7-3930K CPU @ 4.20GHz, 32GB 1333 DDR3, FirePro V5900
TC 21 Platinum (64-Bit) Running on Win7 Pro SP1


* September 08, 2010, 02:21:47 PM
#2
Hello Brad, thanks for the feedback, I actually landed on the hdr site that you have mentioned last week after intensive googling. I downloaded most of the HDR utilities, including picturenaut. I have not had time to try them out as yet, but will delve into it sometime this week. I did not know about the flexify plugin, but it really does seem to have a vast array of transformations, and I may try the demo plugin this week also. I think that the environment maps have great potential if you can customize them for a particular model.Money is a bit thin on the ground at present, but I intend to eventually develop some engineering cube maps for my engineering model prints. I could for example create a cube with continuous pipework connecting it's internal faces in turbocad, and then map each view onto a cube map, then this cubemap would create the surrounding pipework reflections on the real pipework . All as and when time allows at present, but getting there a bit at a time.

Again many thanks for your input.

                                                    Mike Geraghty.

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September 08, 2010, 03:43:23 PM
#3
I'm excited to see what you come up with Michael. Your idea sounds very interesting. If you're looking for some very good reading on the subject of HDR, especially as it relates to 3D rendering, you might checkout the "HDRI Handbook" by Christian Bloch. It's very informative.

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BradE [ dean3Design ]
Core i7-3930K CPU @ 4.20GHz, 32GB 1333 DDR3, FirePro V5900
TC 21 Platinum (64-Bit) Running on Win7 Pro SP1


* September 09, 2010, 08:06:04 AM
#4
Hello again Brad, the Flexify 2 plugin is excellent, only just started playing around with it, and trying to fathom out how much rotation to add to each side of the cube to get the alignment right. A little bit of trial and error at the moment. You cannot export the sides in the demo, but can get the cross that you can then cut up into the separate faces. This will be next on my purchase  list when funds allow.

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* September 13, 2010, 09:51:43 AM
#5
Just out of interest Brad, relating to HDR images. Is it possible to have a sky luminence in a scene that will traverse the sky at certain intervals, and save each rendering and then merge the renderings to create a HDR image. I am only just getting my head around the HDR methodology, but it would be interesting to create HDR images from renders with different lighting parameters, as opposed to photographs taken at different times of day of the same scene.

What is your take on this possibility ?.

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September 15, 2010, 06:55:02 AM
#6
Just out of interest Brad, relating to HDR images. Is it possible to have a sky luminence in a scene that will traverse the sky at certain intervals, and save each rendering and then merge the renderings to create a HDR image. I am only just getting my head around the HDR methodology, but it would be interesting to create HDR images from renders with different lighting parameters, as opposed to photographs taken at different times of day of the same scene.

What is your take on this possibility ?.

The idea behind HDR is to gather as much lighting information as possible from a scene and store to that information as a 32-bit digital image. This is done by acquiring at least (3) LDR images of differing exposure and merging those into an HDR image via special software.

The dynamic range of the light in a scene is essentially the difference between its darkest and brightest areas. The dynamic range of light in a room with the sun spilling in through a window would be much higher than the same room lit by only incandescent light bulbs. The higher the dynamic range, the more exposures you'll need to effectively cover that range.

To capture the light information you start by taking a snapshot that properly exposes the darkest area of the scene (generally the shadows). Then you adjust the exposure up by 1 or 2 stops and take another snapshot. Continue taking shots, while increasing the exposure by the same increment each time, until the brightest area of the scene is properly exposed. Now you have a collection of images that represents the dynamic range of your scene. When merging these into an HDR image most software will ask you for the increment of exposure used and some will just guess.

Basically, the idea is to capture the images as quickly as possible rather than throughout a day. This is most important with outside scenes because cars, birds, trees, clouds, etc. all move which makes merging the images a big job. It becomes less automatic and much more hands-on to align and edit out portions of the images.

So, to answer your question Michael, I haven't tried generating an HDRI from multiple renderings. I think you could certainly generate a usable file that way with some trial and error. I've seen many posts in various forums on the subject of "faking" HDR. I think the trick would be setting up the scene once and then adjusting the luminance brightness to follow a typical capturing sequence. As mentioned above, the exposure difference between images needs to be consistent for merging software to reliably merge the images into a single HDRI.

I'd love to see what you come up with while experimenting.

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BradE [ dean3Design ]
Core i7-3930K CPU @ 4.20GHz, 32GB 1333 DDR3, FirePro V5900
TC 21 Platinum (64-Bit) Running on Win7 Pro SP1


* September 15, 2010, 01:11:09 PM
#7
Thanks for the feedback Brad, very informative. I must admit , that I had the wrong idea about HDR, and thought that the frames were taken at different times rather than in close proximity. I will give the model with adjusted lighting a try in the next couple of days, and see what I come up with. I did notice that you said 32bit images, is this for a broader spectum or is it just the norm. I see now how the incresing length exposure time captures the various range of brightness, which lets me get my head around the concept better.

Many Thanks again !.

                                  Mike Geraghty.

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September 17, 2010, 07:14:34 AM
#8
RE: I did notice that you said 32bit images, is this for a broader spectrum or is it just the norm?

The norm for HDR is 32bit in the Radiance format (.hdr). There are several other formats out there and compression technology is improving. TurboCAD can use both .hdr and .exr (OpenEXR). OpenEXR currently produces a smaller file. A standard LDR, or typical, image stores only 8bits of information per color channel. Those extra bits in HDR are where all that lighting information is stored.

A single LDR image can capture around 5 to 8 EVs. The human eye comprehends roughly 14 EVs. An HDR image can easily cover 17 to 20 EVs from a typical scene. Tone mapping an HDR image is essentially squashing all of that info back into a range that can be printed or viewed on a computer monitor. An example of the benefits of tone mapping is the ability to properly expose light inside a room and outside a window on a sunny day in the same image.

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BradE [ dean3Design ]
Core i7-3930K CPU @ 4.20GHz, 32GB 1333 DDR3, FirePro V5900
TC 21 Platinum (64-Bit) Running on Win7 Pro SP1