I've made a couple previous runs at using the relatively new tiling 
patterns finding some things working and others not. Today finally 
figured out the tiling pattern requires 7 significant digits in the map 
file used with the pattern when into values like 0.316666...

The scenes/textures/patterns/tiling.pov example writes only 4 
significant digits & I was using that code to create my maps.

I'd suggest updating the tiling example to write 7 significant digits  & 
perhaps a note about this should made in the documentation too. Tiling 
23,3 is an example with the issue should folks want to verify.

Not really sure why more accuracy is required. It only affects parts of 
some tiles within any given tiling pattern with the issue.

Bill P.

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On 23/08/2014 18:51, William F Pokorny wrote:
> I've made a couple previous runs at using the relatively new tiling
> patterns finding some things working and others not. Today finally
> figured out the tiling pattern requires 7 significant digits in the map
> file used with the pattern when into values like 0.316666...
> 
> The scenes/textures/patterns/tiling.pov example writes only 4
> significant digits & I was using that code to create my maps.
> 
> I'd suggest updating the tiling example to write 7 significant digits  &
> perhaps a note about this should made in the documentation too. Tiling
> 23,3 is an example with the issue should folks want to verify.
> 
> Not really sure why more accuracy is required. It only affects parts of
> some tiles within any given tiling pattern with the issue.
> 
> Bill P.

You should use fraction, it is simpler and not limited in precision
(well, let povray handles that point).

Tiling 23 is using 3 tiles, how do you split 1.0 in 3 parts of same
size, when the underluying arithmetic is bound to binary representation ?

Now, maybe an update of the scenes/textures/patterns/tiling.pov example ?

-- 
IQ of crossposters with FU: 100 / (number of groups)
IQ of crossposters without FU: 100 / (1 + number of groups)
IQ of multiposters: 100 / ( (number of groups) * (number of groups))

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On 08/23/2014 12:59 PM, Le_Forgeron wrote:
>
> You should use fraction, it is simpler and not limited in precision
> (well, let povray handles that point).
>
> Tiling 23 is using 3 tiles, how do you split 1.0 in 3 parts of same
> size, when the underluying arithmetic is bound to binary representation ?
>
> Now, maybe an update of the scenes/textures/patterns/tiling.pov example ?
>
Agree, all good points. I admit to just using the tiling.pov's WriteMap 
feature to get the maps in large part because I didn't understand how 
the tiling pattern worked.

... I used this feature of the example
// change to yes to write the color_map to a text file
#declare WriteMap = no;
...

The quick fix to tiling.pov for the WriteMap feature above is just :

71,72c71,72
<             #write (MapFile, "    [", str(V2/TileTypes,5,4)," rgb <", 
vstr(3, ThisColor,", ", 0,4),">]\n")
<             #write (MapFile, "    [", str((V2+incre)/TileTypes,5,4)," 
rgb <", vstr(3, ThisColor,", ", 0,4),">]\n")
---
 >             #write (MapFile, "    [", str(V2/TileTypes,5,7)," rgb <", 
vstr(3, ThisColor,", ", 0,4),">]\n")
 >             #write (MapFile, "    [", str((V2+incre)/TileTypes,5,7)," 
rgb <", vstr(3, ThisColor,", ", 0,4),">]\n")

Even getting the color tiles I expect, I still don't understand 
everything about this tiling pattern. I didn't expect the pattern to 
plateau (or perhaps it peaks and recedes) inside the tiles? Rather I 
thought there would be a continued gradient to the center making 
impossible the sensitivity to mathematical noise in the map we see.

I'll see if tomorrow I can find some time to update so a fractional 
representation map is written to the WriteMap file instead of the fix 
above. Perhaps too adjusting the break points slightly more away from 
the apparent calk/tile edges of the pattern if I can get a better 
understanding of the gradients. Guess I can plot the whole thing as one 
gradient to better see what it is really doing in the tiles.

Bill P.

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On 23/08/2014 21:09, William F Pokorny wrote:

> 
> Even getting the color tiles I expect, I still don't understand
> everything about this tiling pattern. I didn't expect the pattern to
> plateau (or perhaps it peaks and recedes) inside the tiles? Rather I
> thought there would be a continued gradient to the center making
> impossible the sensitivity to mathematical noise in the map we see.
> 

the smallest tile (such as in 23) provide the limit for the size of the
calk of all tiles. The inner part, deeper, of other tiles are getting
uniform entry. At best, the smallest one becomes 100% calk, but a part
of the other ones remains (unless they have the same depth).

The calk is parallel to the side of the tile, and it appeared on the
part of the map (so you can have a banded calk around a tile).

> I'll see if tomorrow I can find some time to update so a fractional
> representation map is written to the WriteMap file instead of the fix
> above. Perhaps too adjusting the break points slightly more away from
> the apparent calk/tile edges of the pattern if I can get a better
> understanding of the gradients. Guess I can plot the whole thing as one
> gradient to better see what it is really doing in the tiles.
> 
> Bill P.
> 


-- 
IQ of crossposters with FU: 100 / (number of groups)
IQ of crossposters without FU: 100 / (1 + number of groups)
IQ of multiposters: 100 / ( (number of groups) * (number of groups))

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On 08/23/2014 04:47 PM, Le_Forgeron wrote:
>
> the smallest tile (such as in 23) provide the limit for the size of the
> calk of all tiles. The inner part, deeper, of other tiles are getting
> uniform entry. At best, the smallest one becomes 100% calk, but a part
> of the other ones remains (unless they have the same depth).
>
> The calk is parallel to the side of the tile, and it appeared on the
> part of the map (so you can have a banded calk around a tile).
>
Thank you for the explanation and hint about banded calk being possible. 
I now have a much better understanding our tiling pattern.

As for a more complete update of the tiling.pov example code, I believe 
changing the following two lines from :

#write (MapFile, "    [",str(V2/TileTypes,5,4)," rgb <", vstr(3, 
ThisColor,", ", 0,4),">]\n")
#write (MapFile, "    [",str((V2+incre)/TileTypes,5,4)," rgb <", vstr(3, 
ThisColor,", ", 0,4),">]\n")

to :

#write (MapFile, "    [(",str(V2,0,3),"/",str(TileTypes,0,0),") rgb <", 
vstr(3, ThisColor,", ", 0,4),">]\n")
#write (MapFile, " 
[(",str(V2,0,3),"+",str(incre,0,3),")/",str(TileTypes,0,0)," rgb <", 
vstr(3, ThisColor,", ", 0,4),">]\n")


implements the fractional map indexes you suggested.

Bill P.

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