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Am 25.07.2016 um 10:32 schrieb Stephen:
> On 7/25/2016 8:21 AM, Thomas de Groot wrote:
>> On 25-7-2016 8:57, Thomas de Groot wrote:
>>> On 24-7-2016 18:09, clipka wrote:
>>>> Am 24.07.2016 um 12:50 schrieb Thomas de Groot:
>>>>
>>>>> Also be aware that in a density pattern colours are
>>>>> interpreted as grey tints.
>>>>
>>>> Actually, no, they're not. They do modify the media's effective colour.
>>>>
>>>
>>> Yes, but are the 'colours' used /inside/ the density statements not read
>>> as grey tints? That is what I have understood (which doesn't mean
>>> anything of course). ;-)
>>
>> I looked that up and was put back right on my feet again. I must have an
>> alternate universe documentation file in my head... :-)
>
> That's what I thought. That it averaged the colour values.
> Where about in the documentation. Do you have a reference?
It is neither a grey value, nor a plain average.
I suspect your misconceptions may have their roots somewhere in the fact
that there are two knobs available to introduce colour to media: The
`emission`, `scattering` or `absorption` statement, respectively, and
the `density` statement.
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On 7/25/2016 9:56 AM, clipka wrote:
> Am 25.07.2016 um 10:32 schrieb Stephen:
>> On 7/25/2016 8:21 AM, Thomas de Groot wrote:
>>> On 25-7-2016 8:57, Thomas de Groot wrote:
>>>> On 24-7-2016 18:09, clipka wrote:
>>>>> Am 24.07.2016 um 12:50 schrieb Thomas de Groot:
>>>>>
>>>>>> Also be aware that in a density pattern colours are
>>>>>> interpreted as grey tints.
>>>>>
>>>>> Actually, no, they're not. They do modify the media's effective colour.
>>>>>
>>>>
>>>> Yes, but are the 'colours' used /inside/ the density statements not read
>>>> as grey tints? That is what I have understood (which doesn't mean
>>>> anything of course). ;-)
>>>
>>> I looked that up and was put back right on my feet again. I must have an
>>> alternate universe documentation file in my head... :-)
>>
>> That's what I thought. That it averaged the colour values.
>> Where about in the documentation. Do you have a reference?
>
> It is neither a grey value, nor a plain average.
>
And it is?
...
> I suspect your misconceptions may have their roots somewhere in the fact
> that there are two knobs available to introduce colour to media: The
> `emission`, `scattering` or `absorption` statement, respectively, and
> the `density` statement.
>
I'm thinking of the value that the `density` statement passes to the
media statement. Which it gets from the df3 file.
--
Regards
Stephen
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On 25-7-2016 10:32, Stephen wrote:
> On 7/25/2016 8:21 AM, Thomas de Groot wrote:
>> On 25-7-2016 8:57, Thomas de Groot wrote:
>>> On 24-7-2016 18:09, clipka wrote:
>>>> Am 24.07.2016 um 12:50 schrieb Thomas de Groot:
>>>>
>>>>> Also be aware that in a density pattern colours are
>>>>> interpreted as grey tints.
>>>>
>>>> Actually, no, they're not. They do modify the media's effective colour.
>>>>
>>>
>>> Yes, but are the 'colours' used /inside/ the density statements not read
>>> as grey tints? That is what I have understood (which doesn't mean
>>> anything of course). ;-)
>>>
>>
>> I looked that up and was put back right on my feet again. I must have an
>> alternate universe documentation file in my head... :-)
>>
>
> That's what I thought. That it averaged the colour values.
> Where about in the documentation. Do you have a reference?
>
In the media section [3.4.8.4.2 Density with color_map]. In the wiki
that probably is at a different paragraph number.
Like you, was under the impression that colour values were averaged and
I don't remember where I got that notion from :-(
--
Thomas
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Stephen <mca### [at] aol com> wrote:
> I'm thinking of the value that the `density` statement passes to the
> media statement. Which it gets from the df3 file
Is it possible your thinking of the hf_gray_16 output file, of which the docs
say:
height = 0.3 * red + 0.59 * green + 0.11 * blue
I took a look at the documentation regarding df3 and didn't see anything
relating to this same formula, except I'm going to guess it might be used when a
df3 is put into a normal {} statement.
I sure can't say what's what about this, just thought I would mention what it
made me think of and that was the height field formula above.
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On 7/25/2016 11:58 AM, Thomas de Groot wrote:
>>> I looked that up and was put back right on my feet again. I must have an
>>> alternate universe documentation file in my head... :-)
>>>
>>
>> That's what I thought. That it averaged the colour values.
>> Where about in the documentation. Do you have a reference?
>>
>
> In the media section [3.4.8.4.2 Density with color_map]. In the wiki
> that probably is at a different paragraph number.
>
> Like you, was under the impression that colour values were averaged and
> I don't remember where I got that notion from :-(
But it says:
The pattern function returns a value from 0.0 to 1.0 and the value is
passed to the color map to compute what color or blend of colors is used.
When I said "averaged" I meant it in the non technical sense.
So that is what I was thinking about. That value is not a vector.
When I made colour df3's I made them using R, G & Blue filters. Then
combined them in three media statements. It was clean and simple.
--
Regards
Stephen
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On 7/25/2016 11:55 AM, omniverse wrote:
> Stephen <mca### [at] aolcom> wrote:
>> I'm thinking of the value that the `density` statement passes to the
>> media statement. Which it gets from the df3 file
>
> Is it possible your thinking of the hf_gray_16 output file, of which the docs
> say:
>
> height = 0.3 * red + 0.59 * green + 0.11 * blue
>
It could very well be. It looks as if some thought has gone into the
formula. :)
> I took a look at the documentation regarding df3 and didn't see anything
> relating to this same formula, except I'm going to guess it might be used when a
> df3 is put into a normal {} statement.
>
Pause for thought. I've never considered using one in a normal
statement. I've only used them with media.
> I sure can't say what's what about this, just thought I would mention what it
> made me think of and that was the height field formula above.
>
One of those things we thing we know and when you look closely. You find
you don't. :)
--
Regards
Stephen
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Am 25.07.2016 um 11:35 schrieb Stephen:
> On 7/25/2016 9:56 AM, clipka wrote:
>> Am 25.07.2016 um 10:32 schrieb Stephen:
>>> On 7/25/2016 8:21 AM, Thomas de Groot wrote:
>>>> On 25-7-2016 8:57, Thomas de Groot wrote:
>>>>> On 24-7-2016 18:09, clipka wrote:
>>>>>> Am 24.07.2016 um 12:50 schrieb Thomas de Groot:
>>>>>>
>>>>>>> Also be aware that in a density pattern colours are
>>>>>>> interpreted as grey tints.
>>>>>>
>>>>>> Actually, no, they're not. They do modify the media's effective
>>>>>> colour.
>>>>>>
>>>>>
>>>>> Yes, but are the 'colours' used /inside/ the density statements not
>>>>> read
>>>>> as grey tints? That is what I have understood (which doesn't mean
>>>>> anything of course). ;-)
>>>>
>>>> I looked that up and was put back right on my feet again. I must
>>>> have an
>>>> alternate universe documentation file in my head... :-)
>>>
>>> That's what I thought. That it averaged the colour values.
>>> Where about in the documentation. Do you have a reference?
>>
>> It is neither a grey value, nor a plain average.
>>
>
> And it is?
> ....
Just the plain colour.
>> I suspect your misconceptions may have their roots somewhere in the fact
>> that there are two knobs available to introduce colour to media: The
>> `emission`, `scattering` or `absorption` statement, respectively, and
>> the `density` statement.
>>
>
> I'm thinking of the value that the `density` statement passes to the
> media statement. Which it gets from the df3 file.
Uh... no, `density` does /not/ get its value from "the df3 file". It
gets its value (which is actually a colour) from a `density_map` and
pattern.
That pattern /can/ be a df3 file, using the `density_file` pattern, but
it is just one of many options.
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On 7/25/2016 4:19 PM, clipka wrote:
>> And it is?
>> >....
> Just the plain colour.
>
>>> >>I suspect your misconceptions may have their roots somewhere in the fact
>>> >>that there are two knobs available to introduce colour to media: The
>>> >>`emission`, `scattering` or `absorption` statement, respectively, and
>>> >>the `density` statement.
>>> >>
>> >
>> >I'm thinking of the value that the `density` statement passes to the
>> >media statement. Which it gets from the df3 file.
> Uh... no, `density` does/not/ get its value from "the df3 file". It
> gets its value (which is actually a colour) from a `density_map` and
> pattern.
>
> That pattern/can/ be a df3 file, using the `density_file` pattern, but
> it is just one of many options.
>
I appreciate the lesson in logic but I am not being paid to write a
spec. :-P
And thanks for the answer, btw. :)
--
Regards
Stephen
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> Stephen <mca### [at] aolcom> wrote:
>> I'm thinking of the value that the `density` statement passes to the
>> media statement. Which it gets from the df3 file
>
> Is it possible your thinking of the hf_gray_16 output file, of which the docs
> say:
>
> height = 0.3 * red + 0.59 * green + 0.11 * blue
>
> I took a look at the documentation regarding df3 and didn't see anything
> relating to this same formula, except I'm going to guess it might be used when a
> df3 is put into a normal {} statement.
>
> I sure can't say what's what about this, just thought I would mention what it
> made me think of and that was the height field formula above.
>
>
>
A DF3 file is intrinsicaly gray level based. It's linearly encoded on 8,
16 or 24 bits.
If you want to have colours, you need one or both of:
A non-gray emission, absorbtion or scattering value.
A non-gray colour map associated with the density.
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Le 16-07-25 à 06:58, Thomas de Groot a écrit :
> On 25-7-2016 10:32, Stephen wrote:
>> On 7/25/2016 8:21 AM, Thomas de Groot wrote:
>>> On 25-7-2016 8:57, Thomas de Groot wrote:
>>>> On 24-7-2016 18:09, clipka wrote:
>>>>> Am 24.07.2016 um 12:50 schrieb Thomas de Groot:
>>>>>
>>>>>> Also be aware that in a density pattern colours are
>>>>>> interpreted as grey tints.
>>>>>
>>>>> Actually, no, they're not. They do modify the media's effective
>>>>> colour.
>>>>>
>>>>
>>>> Yes, but are the 'colours' used /inside/ the density statements not
>>>> read
>>>> as grey tints? That is what I have understood (which doesn't mean
>>>> anything of course). ;-)
>>>>
>>>
>>> I looked that up and was put back right on my feet again. I must have an
>>> alternate universe documentation file in my head... :-)
>>>
>>
>> That's what I thought. That it averaged the colour values.
>> Where about in the documentation. Do you have a reference?
>>
>
> In the media section [3.4.8.4.2 Density with color_map]. In the wiki
> that probably is at a different paragraph number.
>
> Like you, was under the impression that colour values were averaged and
> I don't remember where I got that notion from :-(
>
You may get average-like or looking results when the path through the
media cross areas that have different coloration.
In emissive media, you get an additive result, and absorbing media is
subtractive.
With scattering medias, you get a mix of the two.
This is in turn combined with whatever background you may have.
Alain
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