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Texture mapping experiment - Printable Version

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Re: Texture mapping experiment - Travis Cobbs - 2012-12-02

Philippe Hurbain Wrote:- Resolution (here 300dpi) looks fairly low, despite a rather large image size.

When you view the part all by itself and have it fill the window, the resolution is iffy. However, if you included the part inside a model and view the model, I think the resolution is plenty high enough.

Also, are you positive your images are 300DPI when displayed at actual size? When I view the image on my screen (at around 100DPI), the graphics are about 4.25" from the leftmost black part to the rightmost black part. Is that distance really less than 1.5" in real life? (I don't have this sticker.)


Re: Texture mapping experiment - Philippe Hurbain - 2012-12-02

Quote:However, if you included the part inside a model and view the model, I think the resolution is plenty high enough.
You are probably right...
Quote:Also, are you positive your images are 300DPI
Definitely, yes. Physical part length is 2 inches, and image size is 600 pixels.


Re: Texture mapping experiment - Michael Heidemann - 2012-12-02

Code:
I tried to substitute yellow and red values obtained from LDconfig.ldr,

Can you please explain why you do that.
In my opinion a picture (and a scan is a picture) should stay the way it is created. I would never try to substitude a color on a scanned sticker with a color from LDConfig.ldr. I think in most cases the result is not the same. On the other hand we have the direct colors introduced just fot pattern because the colors do match to LDconfig.ldr very seldom. So I am irritating by your attempt, but I guess you have a good reason for that ? Smile


Re: Texture mapping experiment - Alex Taylor - 2012-12-02

First, scanners are not accurate. The colours you get back will not be the same as the colours of the original image.

Second, the LDConfig.ldr colours are not accurate. They are best-approximations to the actual LEGO colours, adjusted to look 'right' on a typical computer monitor. Not that monitors are particularly accurate either... :-)

Third, in this particular case, the sticker is supposed to be the same colour as the part it's being applied to, so it is entirely reasonable to use the LDConfig colours for it.


Re: Texture mapping experiment - Philippe Hurbain - 2012-12-02

In the general case, I agree with you... even though color calibration is a VERY complex matter, involving scanner, screen, rendering software, etc. You also have to live with real life devices, eg. here, colors are not even uniform from one end to the other end of the sticker, despite my scanner is reasonnably good (it's an Epson V30).

But for this model, stickers are stuck on same color parts, and in real life they blend very well with the substrate. Raw scans clearly didn't... Actually, several of the stickers are half red/half yellow, and are stuck on red and yellow panels to form a seamless diagonal line (see http://shop.lego.com/en-US/Helicopter-9396). Clearly color match should be perfect!

Edit - just saw Alex post... we pretty much agree Wink


Re: Texture mapping experiment - Michael Heidemann - 2012-12-02

I agree fully with you regarding the colors. But I would solve that in a different way. If one color in computer does not match the real color I would tune the computer color of the whole picture. Not only one specific color.
Because if one color does not match I belive that also all other colors on the sticker are not correct .


Re: Texture mapping experiment - Alex Taylor - 2012-12-02

Michael Heidemann Wrote:I agree fully with you regarding the colors. But I would solve that in a different way. If one color in computer does not match the real color I would tune the computer color of the whole picture. Not only one specific color.
Because if one color does not match I belive that also all other colors on the sticker are not correct .

...which is what he did ;-)


Re: Texture mapping experiment - Travis Cobbs - 2012-12-03

Just as a note, you can set the yellow part of the texture to be clear, and then set the underlying part geometry to be yellow, and the problem should go away. Antialiasing around the printed bits can get complicated, though.

Note that this is NOT the same thing as trying to set the yellow part of the sticker to be transparent. You'd be setting the yellow part of the texture to be yellow, but since the texture would then be applied over yellow geometry, the sticker itself would still be yellow for that section.


Re: Texture mapping experiment - Tim Gould - 2012-12-03

Hey Travis, could you illustrate with a pic? I'm not sure I understand you. Not that I'll be doing anything like this anytime soon, but it would be nice to have it demonstrated Smile


Re: Texture mapping experiment - Philippe Hurbain - 2012-12-03

I should have thought of that! Excellent idea.
It can even kill two birds with the same stone... eg. for diagonal line stickers 1 and 2 in this sheet, you set sticker top red/silver/yellow, and add only fine grid details as texmap. And the colored sticker top can act as a fall back for non-texmap able viewers. This is another example where imho 0 !FALLBACK should be made optionnal, fall back geometry and projection geometry are the same.