Op 7-10-2023 om 23:12 schreef Samuel B.:
> It looks a bit improved (or maybe just different), but I still see artifacts
> characteristic of an 8-bit height map. The problem is that you can't add any
> in-between elevations you didn't originally create... so, while the new image
> might be a higher bit-depth, it will still contain the same stair-stepping
> produced by the original 8-bits-per-channel image. (It might look slightly
> different due to changes in the gamma level, or any up/down-scaling you might
> have done, or something else, but the issue will remain.)
> 
Right. I see what you mean (although I don't really see the "shaggies" 
but you probably have a better screen, and better eyes, than I have ;-) ).

> I can see two main options at this moment: 1) create a new height map starting
> with an 16 bits per channel format, and painting everything again; or 2) convert
> the map to 16 bit grayscale, upscale x2, blur slightly, and then downscale back
> to the original x & y resolution using a good interpolation method. You will
> lose some details with the second option. A third option might be to convert to
> 16-bit gray scale and then play with the blur and smudge tools, which would let
> you put in some new details you might have wanted to add.
> 
OK. I shall take this into account for future maps. I consider the 
present one as a testing object.

> I don't know exactly what your goals are, but can some things be done using
> pigment maps and/or functions?
> 
Basically, I use the image_map within a height_field function, more or 
less warped, and then sheared using a matrix.

I attach in p.b.s-f a zip containing a simplified scene file + the 
height_field image_map.

-- 
Thomas

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Thomas de Groot <tho### [at] degrootorg> wrote:
> Op 7-10-2023 om 23:12 schreef Samuel B.:
> > It looks a bit improved (or maybe just different), but I still see artifacts
> > characteristic of an 8-bit height map. The problem is that you can't add any
> > in-between elevations you didn't originally create... so, while the new image
> > might be a higher bit-depth, it will still contain the same stair-stepping
> > produced by the original 8-bits-per-channel image. [...]
> >
> Right. I see what you mean (although I don't really see the "shaggies"
> but you probably have a better screen, and better eyes, than I have ;-) ).

In the images you posted, I can't see individual height_field 'pixels,' but what
I do see is diffuse light being reflected only at certain angles, similar to a
'toon shader. It's a general lack of smoothness that the smooth keyword can't
touch... It's the same thing I've seen with free height maps found online.

> > I don't know exactly what your goals are, but can some things be done using
> > pigment maps and/or functions?
> >
> Basically, I use the image_map within a height_field function, more or
> less warped, and then sheared using a matrix.

Ah, ok. There are ways of ditching the matrix shears and doing everything
entirely with functions, but it would require somewhat extensive changes to the
code. And the result would not be the same :/

> I attach in p.b.s-f a zip containing a simplified scene file + the
> height_field image_map.
>
> --
> Thomas

I downloaded and rendered the scene. The result looks a lot smoother than the
images you posted... Did you use a dilate operation on the height_map? It seems
to have worked pretty well!

Sam

Btw, 'CamZoom' doesn't seem to do anything. Changing the camera's angle to this
makes it work: CamAng/CamZoom

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Op 08/10/2023 om 22:36 schreef Samuel B.:
> In the images you posted, I can't see individual height_field 'pixels,' but what
> I do see is diffuse light being reflected only at certain angles, similar to a
> 'toon shader. It's a general lack of smoothness that the smooth keyword can't
> touch... It's the same thing I've seen with free height maps found online.
> 
I wonder if you do no interpret here the granite normals from the used 
(complex) rock texture...? See below.

>>> I don't know exactly what your goals are, but can some things be done using
>>> pigment maps and/or functions?
>>>
>> Basically, I use the image_map within a height_field function, more or
>> less warped, and then sheared using a matrix.
> 
> Ah, ok. There are ways of ditching the matrix shears and doing everything
> entirely with functions, but it would require somewhat extensive changes to the
> code. And the result would not be the same :/
> 
Hmmm... I am not /that/ proficient with functions I am afraid, but it is 
a way I certainly want to explore more in detail.

> I downloaded and rendered the scene. The result looks a lot smoother than the
> images you posted... Did you use a dilate operation on the height_map? It seems
> to have worked pretty well!
> 
See above. As I did not change anything to the image_map, your comment 
seems to partly confirm the 'normals' hypothesis... ;-)

[ex cathedra]
My playing with the warp {turbulence ...} had the interesting effect of 
nicely simulating what is known as 'loading' in sedimentology: 
alternating layers of unconsolidated, water-saturated, sediments 
(sand/clay), for example in tidal basins with a high sediment input. 
Differential compaction of those sediments may generate 'loading' 
deformation of the coarser sediments into the finer ones. Earthquakes 
can generate those same features by 'liquefying' soft sediments.
[/ex cathedra]

> 
> Btw, 'CamZoom' doesn't seem to do anything. Changing the camera's angle to this
> makes it work: CamAng/CamZoom
> 
I know. CamZoom is just there in case it is needed. It is in fact a 
relict from another scene I didn't bother to ditch. :-)

-- 
Thomas

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Op 9-10-2023 om 08:37 schreef Thomas de Groot:
> Op 08/10/2023 om 22:36 schreef Samuel B.:
>> Btw, 'CamZoom' doesn't seem to do anything. Changing the camera's 
>> angle to this
>> makes it work: CamAng/CamZoom
>>
> I know. CamZoom is just there in case it is needed. It is in fact a 
> relict from another scene I didn't bother to ditch. :-)
> 
Just for completeness sake, I checked; it originally came from the 
original iso2pov scene codes by Jaime. I do not remember having checked 
its correct working...

-- 
Thomas

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Thomas de Groot <tho### [at] degrootorg> wrote:
> Op 08/10/2023 om 22:36 schreef Samuel B.:
> > [...] It's a general lack of smoothness [...]
> >
> I wonder if you do no interpret here the granite normals from the used
> (complex) rock texture...? See below.

Yeah, it's quite possible. Also, other differences in shading, colors and aa
could have something to do with my perception of things.

> [ex cathedra]
> My playing with the warp {turbulence ...} had the interesting effect of
> nicely simulating what is known as 'loading' in sedimentology:
> alternating layers of unconsolidated, water-saturated, sediments
> (sand/clay), for example in tidal basins with a high sediment input.
> Differential compaction of those sediments may generate 'loading'
> deformation of the coarser sediments into the finer ones. Earthquakes
> can generate those same features by 'liquefying' soft sediments.
> [/ex cathedra]

It's very fascinating. I'm sure the layers could tell you a lot about the makeup
and history of the surrounding landscape... And I bet one could find heavier
minerals at the bottoms of various basins, given enough disturbance of the
sediments during and after deposition. Gold, if present, will of course settle
toward the bottoms of things, but other stuff is sure to settle in as well. Many
precious & semi-precious gems (ruby, garnet, etc.) are denser than other
minerals. In fact, there's a local creek where small red garnets can be found
alongside gold, provided the panning step isn't done too aggressively.

> > Btw, 'CamZoom' doesn't seem to do anything. Changing the camera's angle to this
> > makes it work: CamAng/CamZoom
> >
> I know. CamZoom is just there in case it is needed. It is in fact a
> relict from another scene I didn't bother to ditch. :-)
>
> [>] Just for completeness sake, I checked; it originally came from the
> original iso2pov scene codes by Jaime. I do not remember having checked
> its correct working...

Its funny how various bits of code tend to collect and deposit themselves in our
scenes over time :D

Sam

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Op 12/10/2023 om 00:40 schreef Samuel B.:
> Thomas de Groot <tho### [at] degrootorg> wrote:
>> Op 08/10/2023 om 22:36 schreef Samuel B.:
>>> [...] It's a general lack of smoothness [...]
>>>
>> I wonder if you do no interpret here the granite normals from the used
>> (complex) rock texture...? See below.
> 
> Yeah, it's quite possible. Also, other differences in shading, colors and aa
> could have something to do with my perception of things.
> 
...which still does not preclude your initial comment obviously. It is 
something I have not been consciously aware of enough.

As a side track to the subject, I am playing also with height field maps 
generated by GeoControl (*.tga). It also provides normal maps (the 
well-known bluish maps) and greyscale maps, both as *.bpm. I want to 
explore if I can usefully add the normal maps to my height fields. It 
looks like it does.

>> [ex cathedra]
>> My playing with the warp {turbulence ...} had the interesting effect of
>> nicely simulating what is known as 'loading' in sedimentology:
>> alternating layers of unconsolidated, water-saturated, sediments
>> (sand/clay), for example in tidal basins with a high sediment input.
>> Differential compaction of those sediments may generate 'loading'
>> deformation of the coarser sediments into the finer ones. Earthquakes
>> can generate those same features by 'liquefying' soft sediments.
>> [/ex cathedra]
> 
> It's very fascinating. I'm sure the layers could tell you a lot about the makeup
> and history of the surrounding landscape... And I bet one could find heavier
> minerals at the bottoms of various basins, given enough disturbance of the
> sediments during and after deposition. Gold, if present, will of course settle
> toward the bottoms of things, but other stuff is sure to settle in as well. Many
> precious & semi-precious gems (ruby, garnet, etc.) are denser than other
> minerals. In fact, there's a local creek where small red garnets can be found
> alongside gold, provided the panning step isn't done too aggressively.
> 
Indeed. However, it all depends on the availability (far of or nearby) 
of source rocks containing or having contained such minerals, as the 
concentrations of gold or heavy minerals (placers!) are the results of 
erosion and then winnowing by streams and other such processes. Even the 
wind can play that role in desert environments. So yes, knowing 
something about the local geology can be very useful.

>>> Btw, 'CamZoom' doesn't seem to do anything. Changing the camera's angle to this
>>> makes it work: CamAng/CamZoom
>>>
>> I know. CamZoom is just there in case it is needed. It is in fact a
>> relict from another scene I didn't bother to ditch. :-)
>>
>> [>] Just for completeness sake, I checked; it originally came from the
>> original iso2pov scene codes by Jaime. I do not remember having checked
>> its correct working...
> 
> Its funny how various bits of code tend to collect and deposit themselves in our
> scenes over time :D
> 
There it is! Erosion and sedimentation in action! :-)

-- 
Thomas

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Thomas de Groot <tho### [at] degrootorg> wrote:
> As a side track to the subject, I am playing also with height field maps
> generated by GeoControl (*.tga). It also provides normal maps (the
> well-known bluish maps) and greyscale maps, both as *.bpm. I want to
> explore if I can usefully add the normal maps to my height fields. It
> looks like it does.

What would the normal maps be useful for, I wonder? We can only change surface
normals via the normal{} block, so any other things for which we would use
normal maps can already be done with slope maps... There's functions I guess,
since I don't think we can use regular slope maps in those... so having a normal
map from another program might be useful there.

> >> [ex cathedra]
> >> My playing with the warp {turbulence ...} had the interesting effect of
> >> nicely simulating what is known as 'loading' in sedimentology [...]
> >
> > It's very fascinating. I'm sure the layers could tell you a lot about the makeup
> > and history of the surrounding landscape [...]
> >
> Indeed. However, it all depends on the availability (far of or nearby)
> of source rocks containing or having contained such minerals, as the
> concentrations of gold or heavy minerals (placers!) are the results of
> erosion and then winnowing by streams and other such processes. Even the
> wind can play that role in desert environments. So yes, knowing
> something about the local geology can be very useful.

Yeah, I think you could find out things about an area that are not otherwise
easily deduced by just studying the nearby bedrock. For instance (and I might've
mentioned this before), but around here there can be found a mineral called
sillimanite. Not only does it impart quartz with a neat opalaescent appearance,
but it can also be use as a gauge, indicating the specific range of temperatures
local minerals formed under at some point in the past. (And that's the extent of
my knowledge regarding the subject ;P)

Sam

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Op 14-10-2023 om 23:56 schreef Samuel B.:
> Thomas de Groot <tho### [at] degrootorg> wrote:
>> As a side track to the subject, I am playing also with height field maps
>> generated by GeoControl (*.tga). It also provides normal maps (the
>> well-known bluish maps) and greyscale maps, both as *.bpm. I want to
>> explore if I can usefully add the normal maps to my height fields. It
>> looks like it does.
> 
> What would the normal maps be useful for, I wonder? We can only change surface
> normals via the normal{} block, so any other things for which we would use
> normal maps can already be done with slope maps... There's functions I guess,
> since I don't think we can use regular slope maps in those... so having a normal
> map from another program might be useful there.
> 
I explored its use out of curiosity. I agree with you about their 
usefulness: it is limited.

>>>> [ex cathedra]
>>>> My playing with the warp {turbulence ...} had the interesting effect of
>>>> nicely simulating what is known as 'loading' in sedimentology [...]
>>>
>>> It's very fascinating. I'm sure the layers could tell you a lot about the makeup
>>> and history of the surrounding landscape [...]
>>>
>> Indeed. However, it all depends on the availability (far of or nearby)
>> of source rocks containing or having contained such minerals, as the
>> concentrations of gold or heavy minerals (placers!) are the results of
>> erosion and then winnowing by streams and other such processes. Even the
>> wind can play that role in desert environments. So yes, knowing
>> something about the local geology can be very useful.
> 
> Yeah, I think you could find out things about an area that are not otherwise
> easily deduced by just studying the nearby bedrock. For instance (and I might've
> mentioned this before), but around here there can be found a mineral called
> sillimanite. Not only does it impart quartz with a neat opalaescent appearance,
> but it can also be use as a gauge, indicating the specific range of temperatures
> local minerals formed under at some point in the past. (And that's the extent of
> my knowledge regarding the subject ;P)
> 
Sillimanite... reminds me of mineral microscopy in my student's years, 
especially because it was so easy to recognise at first sight! :-)

-- 
Thomas

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On 06/10/2023 14:46, Thomas de Groot wrote:
> I may be dim... can you explain?

The scene reminds me of those in western movies or comics where bandits 
are planning a big train robbery.
The grazing light places a lot of emphasis on the sedimentary rock, and 
it seems as if the cowboy is telling others to climb it to observe from 
above.

Paolo

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Op 17/10/2023 om 00:28 schreef Paolo Gibellini:
> On 06/10/2023 14:46, Thomas de Groot wrote:
>> I may be dim... can you explain?
> 
> The scene reminds me of those in western movies or comics where bandits 
> are planning a big train robbery.
> The grazing light places a lot of emphasis on the sedimentary rock, and 
> it seems as if the cowboy is telling others to climb it to observe from 
> above.
> 
Lol! You are perfectly right indeed! I was too much focussed on the 
doggy being trained to climb rocks. :-)

-- 
Thomas

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