3d scan of imperfect globe to a 2d Equirectangular Projection

[Vigilus]

@ Admin(s) could you correct the post name from "equilateral" to "equirectangular" please?

@ Waldronate, I sent you a PM. I don't have access to the atlas mapping as that came with artec studio 12 and I no longer have the seat license.

[Gidde]

Corrected as requested.

[selden]

I'm confused by all this "baking" and stuff. Why not reproject your orthographic image as an equirectangular image and use that as a surface texture on a globe?

FWIW, I used this procedure with your most recent image:
Use IrfanView's "autocrop" menu item to eliminate the border (ImageMagic's "trim" refused to work correctly for me.)

use ImageMagic convert to scale the 748x757 image to be 1024x1024 (I'm rashly assuming that the squashing was linear)
( convert Globe_Game_cropped.png -geometry 1024x1024! GGs.ppm )

use MMPS to project from orthographic to equirectangular (2048x1024)
( project -i orthographic -lat 0 -long 0 -w 2048 -h 1024 -f GGs.ppm > GGso.ppm ; convert GGso.ppm GGso.png )

use Celestia to draw a globe with that surface texture.

Below are framegrabs of the final result. The first framegrab compares the globe drawn by Celestia to your most recent image. The second screengrab is just to show the distortion in the surface texture image at the borders, where they're stretched onto the surface of the sphere. The third picture is the equirectangular surface texture image that I used.

[Vigilus]

@ Selden

Wow! That looks great even in low res. I think this was another way of explaining what Waldronate was talking about earlier (if not feel free to correct me @Waldronate).

I'm going to take some Blender (Orthographic view) renders of the 6 hot-keyed views (left, right, front, back, top, bottom) and see if I can get that to work. I'm trying to take the 3d .obj/jpg file I have and turn it into a high quality, high res 2:1 aspect ratio (equirectangular projection) map.

@Waldronate How to set up my outputs so that your program can take high resolution files to map it? Trying for 8k resolution as an output if I can get it. Thanks!

Getting the precision of the equirectangular projection is key, as I'm trying to have as little distortion as possible when this gets applied to the manufacturer's template. Every small distortion can undo the carefully crafted design that makes the piece so eye catching. The point of the project is to prove that human designs are superior to computer generated RNG "designs", so distortion hurts that cause.

That's a good thing for cartographers everywhere, it increases our market value directly in an employer's eyes.

From a practical board game perspective I can touch it up easily enough and it will look great.

The original artwork was a slowly, exhaustively designed hand painted globe, so its from 3d to 2d; you probably know this, but I state this again just in case.

@Gidde Thanks!

[selden]

@ Selden

Wow! That looks great even in low res. I think this was another way of explaining what Waldronate was talking about earlier (if not feel free to correct me @Waldronate).

I think the processes are similar, although certainly not identical. I prefer scripted solutions, while Waldronate's ReprojectImage has a GUI interface.

I'm going to take some Blender (Orthographic view) renders of the 6 hot-keyed views (left, right, front, back, top, bottom) and see if I can get that to work. I'm trying to take the 3d .obj/jpg file I have and turn it into a high quality, high res 2:1 aspect ratio (equirectangular projection) map.

What types of images did you import to Blender?
(I'm wondering if the use of Blender could be bypassed, with the reprojection done directly, translating just the images.)

However, if the goal is to produce a physical 3D object, .obj models can be used as inputs to 3D printers. I suspect there are better ways to produce accurate spheres with smooth surfaces, though. Or do you intend to produce globes with bumpy, mountainous surfaces?

Coloring the surfaces of those objects is a separate issue, of course, which is what I'm assuming you're trying to do.

@Waldronate How to set up my outputs so that your program can take high resolution files to map it? Trying for 8k resolution as an output if I can get it. Thanks!

What do you consider to be "high resolution?"
Unfortunately, the current version of ReprojectImage seems to have a maximum output resolution of 4Kx2K.

FWIW, the command line program that I use (MMPS project) was able to convert an 8Kx8K orthographic projection to a 16Kx8K equirectangular projection.

Getting the precision of the equirectangular projection is key, as I'm trying to have as little distortion as possible when this gets applied to the manufacturer's template. Every small distortion can undo the carefully crafted design that makes the piece so eye catching. The point of the project is to prove that human designs are superior to computer generated RNG "designs", so distortion hurts that cause.

That's a good thing for cartographers everywhere, it increases our market value directly in an employer's eyes.

From a practical board game perspective I can touch it up easily enough and it will look great.

The original artwork was a slowly, exhaustively designed hand painted globe, so its from 3d to 2d; you probably know this, but I state this again just in case.

@Gidde Thanks!

(to rephrase my initial question)
How are you translating the globe that you created into surface texture images?
Are you using a camera to take pictures of it? If so, what model of camera is it and how many megapixels are involved (since that's how cameras often are rated)?

[Vigilus]

@ Selden

What types of images did you import to Blender?

I imported the .obj file and the UV map as a .jpg file (I didn't know about compression then, wish it was .tiff!)

Or do you intend to produce globes with bumpy, mountainous surfaces?

I'm going for the shading and lighting of the mountains on a physically smooth surface. Cheaper and still pretty to look at, avoiding the annoyance of magnets on bumpy surfaces as well. This is where I think baking would be a good solution.

What do you consider to be "high resolution?"

8192x8192 is what the industry standard is. Although there is a lot of debate, the quality gained for the time to make and find workarounds for programs that don't support high resolutions starts to taper off at that number.

FWIW, the command line program that I use (MMPS project) was able to convert an 8Kx8K orthographic projection to a 16Kx8K equirectangular projection.

I'll have to check that out, thanks for telling me about it.

How are you translating the globe that you created into surface texture images?

The camera at the object's origin, in orthographic view, 6 Renders in Blender along the preset views of: left, right, front, back, top, bottom. 8192x8192, outputting as a .tiff file. I don't know if this is going to work or if these are the correct settings.

Are you using a camera to take pictures of it? If so, what model of camera is it and how many megapixels are involved (since that's how cameras often are rated)?

I originally used an Artec Space Spider to 3d scan the physical globe into the digital medium.

[waldronate]

I think Selden has this under control.

[selden]

I think Selden has this under control.

I don't

Is there any chance that ReprojectImage could be enhanced to handle images as large as 8192 x 8192 ?

While I'm comfortable recompiling and using command-line utilities like MMPS, many people prefer GUIs.

[selden]

I'll have to check that out, thanks for telling me about it.

For more information, see http://www.users.globalnet.co.uk/~arcus/mmps/

A limitation of MMPS is that it was written for Linux. While I found it relatively easy to recompile it for use with Cygwin under Windows 7 (which is what I use), others might be less comfortable doing that. (In principle, at least, I could provide the Windows binaries.) An alternative, if you aren't already using Linux, might be to use one of the Linux environments available for Windows 10.

The camera at the object's origin, in orthographic view, 6 Renders in Blender along the preset views of: left, right, front, back, top, bottom. 8192x8192, outputting as a .tiff file. I don't know if this is going to work or if these are the correct settings.

That procedure seems reasonable to me. Combining the resulting images so their borders aren't noticeable might be challenging.

I originally used an Artec Space Spider to 3d scan the physical globe into the digital medium.

Aha! Not as simplistic as I was thinking.

[waldronate]

Is there any chance that ReprojectImage could be enhanced to handle images as large as 8192 x 8192 ?

http://fracterra.com/ReprojectImage64.zip has a 64-bit installer with no imposed upper limit on size (it will crash when it hits some OS limit or other rather than just refuse to export above a certain size).