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Need way to create sphere segments.


mkp
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It doesn't curved the sphere segments.

 

by using this website I create the following glob:

 

image.jpg

 

Althrough the map itself looks ok, the earth parallels looks like a spider web close to the poles.

 

s3d.jpg

 

The same map using the Shape3D plugin, it looks exactly as it should including the earth parallels.

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Hmm. That seems like a somewhat complex problem. The reason the the lines look straight instead of curved is, of course, that the individual segments are flat, and there's nothing than can be done about that. I'm not sure how exactly that can be compensated for, though there's likely a way. A standard sinusoidal map projection won't do it. Perhaps you or someone else can provide a reference or figure out the proper transformation. If not, I may or may not have time to think about it; and if I do think about it, I may or may not be able to solve it.

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From what I can see, the map gets divided into these 12 surfing board shaped pieces.

 

My radical solution would be:

 

1. Open your map on Paint.NET and make sure it takes the whole canvas. Rename this bottom Background layer as Map.

2. Create a new transparent layer on top.

3. Select this new transparent layer and manually draw the surfing board shape using the Line/Curve tool :LineTool: . Fill it with a solid color like black. Make sure that its width is 1/12 of the canvas size so you might have to resize it using the Move Selected Pixels tool  :MoveTool:. Its top and bottom tips must stretch the height of the canvas too. Move this shape at the very left end of your canvas.

4. Duplicate that layer and use the Move Selected Pixels tool   :MoveTool:  again and just drag to the right and you'll see a duplicate of your shape was made. Make sure to align it with your original shape. You could use the arrow keys in your keyboard to move it slowly and precisely. Merge those 2 shape layers. Duplicate this layer again and drag to the right, you'll that you now have 4 shapes. Repeat the same procedure until you have 12 of these surf board shapes aligned across your canvas.

 

5. Merge all the layers that contain your surf board shapes but DO NOT merge them with your Map layer.

6.Using your magic wand, click your solid color shapes and you'll see that it selects all of them since they are stitched together.

7. Once you have an active selection, uncheck your shapes layer and click on your Map layer.

8.CTRL+I to invert the selection and press Delete on your keyboard. If things went right, you should have something like your example.

9. You may now delete your hidden shapes layer. However, you could copy this layer on a new separate .pdn file in case you might have to reuse it to trace a selection like that again. Create a new layer and fill it with white color. Move this layer at the bottom of your Map layer so it will have a white background instead of a checkerboard.

10. Merge the two layers and save as .png or .jpg.

Edited by Ishi
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I'm confused. Why do you need the segmented development? Why not just wrap the 2D image around a sphere?

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Ah. Right. A physical thingy then. Gotcha ;

I remember 20 sided die (icosahedron) from my Dungeons & Dragons days!

There is an interesting technique which divides the 20 faces of such a polyhedra to form a geodesic grid. Each of the smaller divisions is (I think) an equilateral triangle.

Reference: https://en.wikipedia.org/wiki/Geodesic_grid

Because of the triangles, I wonder if this would be an easier task than creating 'citrus' segments?

Reference: http://math.stackexchange.com/questions/11499/is-it-possible-to-imitate-a-sphere-with-1000-congruent-polygons

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...

3. .. Move this shape at the very left end of your canvas.

4. Duplicate that layer and use the Move Selected Pixels tool   :MoveTool:  again and just drag to the right and you'll see a duplicate of your shape was made. Make sure to align it with your original shape. You could use the arrow keys in your keyboard to move it slowly and precisely. Merge those 2 shape layers. Duplicate this layer again and drag to the right, you'll that you now have 4 shapes. Repeat the same procedure until you have 12 of these surf board shapes aligned across your canvas.

...

It's very easy to achieve precise placing and aligning of objects using MadJik's Panelling plugin.

 

 

...

6.Using your magic wand, click your solid color shapes and you'll see that it selects all of them since they are stitched together.

7. Once you have an active selection, uncheck your shapes layer and click on your Map layer.

8.CTRL+I to invert the selection and press Delete on your keyboard. If things went right, you should have something like your example.

...

One can get a better quality of the same result using Illnab1024's Alpha Mask plugin.

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Xkds4Lh.png

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Ishy,

 

I do not understand the how's and why's of most of the plugins I use. It hasn't kept me from using them.

The Alpha Mask plugin is not as complicated as some but it's one of those you need to try hands-on to figure out how to use.

 

To get this:

335cl5z.png

 

Try this:

23vcg8o.png

 

2uj6136.png

 

 

 

Minus.com, my usual image host, has been acting up for quite some time now. I've uploaded the above images on TinyPic but I really should start looking for another alternative to the fascist market leaders.

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Xkds4Lh.png

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Thanks again Djisves.

 

 

I should try it because it seems to make cleaner edges without using AA's Assistant.

 

 

That was a pretty straightforward example. I could even browse for an outside file to use as mask. Would be quite useful to create textures.

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