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Here's what Australian dollar coins look like, almost. :) I just started
this one last weekend. The coin faces are height fields, the milled edges
are
just normals on a cylinder, using a simple slope map & normal map.
I'm not happy with the finish. I may need to find better source images for
my
height fields to improve the surface, so it reflects like a coin should.
Some dirt and scratch marks on them would help, too, I guess. Also, the
heights are wrong, because highlights are not always on the high points.
For example, see the very heavy looking jawline on the Queen. (Sorry, about
that Liz. :)
The face image originals I used are here:
http://www.australianstamp.com/Coin-web/aust/dollar/dolleli2.htm
but I've smoothed them a bit (maybe a bit too much) using the NetPBM
package.
Suggestions and constructive criticism welcome!
Post a reply to this message
Attachments:
Download 'coind1.jpg' (121 KB)
Preview of image 'coind1.jpg'
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PM 2Ring nous apporta ses lumieres en ce 2005-07-12 09:18:
> Here's what Australian dollar coins look like, almost. :) I just started
> this one last weekend. The coin faces are height fields, the milled edges
> are
> just normals on a cylinder, using a simple slope map & normal map.
>
> I'm not happy with the finish. I may need to find better source images for
> my
> height fields to improve the surface, so it reflects like a coin should.
> Some dirt and scratch marks on them would help, too, I guess. Also, the
> heights are wrong, because highlights are not always on the high points.
> For example, see the very heavy looking jawline on the Queen. (Sorry, about
> that Liz. :)
>
> The face image originals I used are here:
> http://www.australianstamp.com/Coin-web/aust/dollar/dolleli2.htm
> but I've smoothed them a bit (maybe a bit too much) using the NetPBM
> package.
>
> Suggestions and constructive criticism welcome!
>
>
> ------------------------------------------------------------------------
>
In the images you used, the light comes from below. This tend to reverse the aparent
relief. For the
queen head, try the unlabled one from 1998 (1998 <blank><blank> canbera) or the 1997
silver one.
The one from 1990 silver kangaroo also have "conventiona" lighting.
Alain
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I think the problem is that you are using an obliquely illuminated coin
image as a proxy for a heightfield.
For this problem you might get experimental and scan a coin - immersed in a
puddle of red or green food coloring.
The resulting image should have highlights where the optical path through
the food coloring is the shortest.
Crop / filter / scale / reformat as required using your favorite image
editor.
I'll leave the rest to your imagination.
DLM
"PM 2Ring" <nomail@nomail> wrote in message
news:web.42d3c08da576ead11917bb8b0@news.povray.org...
> Here's what Australian dollar coins look like, almost. :) I just started
> this one last weekend. The coin faces are height fields, the milled edges
> are
> just normals on a cylinder, using a simple slope map & normal map.
>
> I'm not happy with the finish. I may need to find better source images for
> my
> height fields to improve the surface, so it reflects like a coin should.
> Some dirt and scratch marks on them would help, too, I guess. Also, the
> heights are wrong, because highlights are not always on the high points.
> For example, see the very heavy looking jawline on the Queen. (Sorry,
about
> that Liz. :)
>
> The face image originals I used are here:
> http://www.australianstamp.com/Coin-web/aust/dollar/dolleli2.htm
> but I've smoothed them a bit (maybe a bit too much) using the NetPBM
> package.
>
> Suggestions and constructive criticism welcome!
>
----------------------------------------------------------------------------
----
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"DLM" <mae### [at] comb umbiumdedu> schreef in bericht
news:42d433ae$1@news.povray.org...
> I think the problem is that you are using an obliquely illuminated coin
> image as a proxy for a heightfield.
>
> For this problem you might get experimental and scan a coin - immersed in
a
> puddle of red or green food coloring.
> The resulting image should have highlights where the optical path through
> the food coloring is the shortest.
> Crop / filter / scale / reformat as required using your favorite image
> editor.
>
Hey! That's a nice trick! :-))
Thomas
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Alain <ele### [at] netscapenet> wrote:
> PM 2Ring nous apporta ses lumieres en ce 2005-07-12 09:18:
> > Here's what Australian dollar coins look like, almost. :) I just started
> >
> heights are wrong, because highlights are not always on the high points.
> > For example, see the very heavy looking jawline on the Queen. (Sorry, about
> > that Liz. :)
> >
> > The face image originals I used are here:
> > http://www.australianstamp.com/Coin-web/aust/dollar/dolleli2.htm
> > but I've smoothed them a bit (maybe a bit too much) using the NetPBM
> > package.
> >
> > Suggestions and constructive criticism welcome!
> >
> >
> > ------------------------------------------------------------------------
> >
> In the images you used, the light comes from below. This tend to reverse the aparent
relief.
Indeed!
>For the queen head, try the unlabled one from 1998 (1998 <blank><blank> canbera) or
the 1997 silver one.
> The one from 1990 silver kangaroo also have "conventiona" lighting.
>
> Alain
Thanks for the suggestions, Alain. I've just had a look at these images &
they look better, but they still have their faults. I'll play with them,
but I think I may need to resort to getting someone to take better photos
for me.
Happy 14th July!
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"DLM" <mae### [at] combumbiumdedu> wrote:
> I think the problem is that you are using an obliquely illuminated coin
> image as a proxy for a heightfield.
Very true, but they were the best looking pics I could find in 30 minutes
with Google. I only realized the lighting angle problem after I'd been
using them for a little while.
> For this problem you might get experimental and scan a coin - immersed in a
> puddle of red or green food coloring.
I agree with Thomas, this is a neat idea!
> The resulting image should have highlights where the optical path through
> the food coloring is the shortest.
I've got a bottle of red ink here that extinguishes the beam of a laser
pointer in less than 3cm. The only camera I own is a B&W security camera
plugged into my trusty old Amiga 2000. Primitive, I know, but I can tape a
10x loupe onto the camera for closeup-work. I think it would give me a
better result for height-field work than my current source images.
OTOH, it'd be a lot easier to persuade a real photographer with modern
equipment to do this for me. :)
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PM 2Ring wrote:
> OTOH, it'd be a lot easier to persuade a real photographer with modern
> equipment to do this for me. :)
I'm not a real photographer, but I have food dye, a scanner and there's
sure to be a dollar coin around here someplace.
I'd like to suggest through that you actually carve the edge of the coin
rather than just making look like its carved. You'll notice your current
image has a flat reflection on the bottom right where the carving is on
the edge.
Give me a couple of hours to get this going and posted to you.
Cheers!
Rick Measham
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Rick Measham <rickm*at%isite.net.au> wrote:
> PM 2Ring wrote:
> > OTOH, it'd be a lot easier to persuade a real photographer with modern
> > equipment to do this for me. :)
>
> I'm not a real photographer, but I have food dye, a scanner and there's
> sure to be a dollar coin around here someplace.
Sounds good!
> I'd like to suggest through that you actually carve the edge of the coin
> rather than just making look like its carved. You'll notice your current
> image has a flat reflection on the bottom right where the carving is on
> the edge.
Sure. I've been trying to decide whether to use CSG or an isosurface. I'll
probably just go with CSG, and save the isosurface for a full isosurface
version, IOW isosurfaces for the coin faces as well as the edge.
> Give me a couple of hours to get this going and posted to you.
Thanks, heaps. Much appreciated, Rick.
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> Rick Measham <rickm*at%isite.net.au> wrote:
>>I'm not a real photographer, but I have food dye, a scanner and there's
>>sure to be a dollar coin around here someplace.
Found a coin, got the food-dye ready. Didn't work. First problem is that
flatbed scanners still have an offset light and so the image is lit from
one direction still.
Second problem is the coin traps air in the food-dye in the etching.
I tried watering down the dye, and it worked a little better, but not much.
The only thing I could think was to use deep enough mixture that the
coin could be flipped around until there was no air pockets. However
that would require some sort of glass container with a perfectly flat
base. I don't have one of those outside of povray!
If you've any more ideas, I'm happy to play!
Cheers!
Rick Measham
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Rick Measham nous apporta ses lumieres en ce 2005-07-16 18:39:
>>Rick Measham <rickm*at%isite.net.au> wrote:
>>
>>>I'm not a real photographer, but I have food dye, a scanner and there's
>>>sure to be a dollar coin around here someplace.
>
>
> Found a coin, got the food-dye ready. Didn't work. First problem is that
> flatbed scanners still have an offset light and so the image is lit from
> one direction still.
>
> Second problem is the coin traps air in the food-dye in the etching.
>
> I tried watering down the dye, and it worked a little better, but not much.
>
> The only thing I could think was to use deep enough mixture that the
> coin could be flipped around until there was no air pockets. However
> that would require some sort of glass container with a perfectly flat
> base. I don't have one of those outside of povray!
And the coin will be out of focus.
>
> If you've any more ideas, I'm happy to play!
>
> Cheers!
> Rick Measham
Can you flip it all over? Like put the scaner on top of the coin?
Another way, Stick some short tube on the scaner glass plate, make the join water
tight (tape, water
based glue,...), put the die in the tube then the coin in the die, scan. Clean
everything.
Alain
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