On 5/1/2017 1:06 PM, Stephen wrote:
> On 5/1/2017 12:11 PM, Thomas de Groot wrote:

>>
>> Indeed, yes. Take my image as example, the dragon is scaled 0.01, the
>> egg 0.25, the cube is not scaled, and the floor 0.50. It seems best to
>> use a standard mm_per_unit and change translucency as needed.
>>
>

Another thought:
If you use the same material for your three objects. There should be no 
difference in the look of the objects. That might be a way to check if I 
am talking rubbish or not. And I am talking about meshes not primitives.

-- 

Regards
     Stephen

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Le 17-05-01 à 02:50, Thomas de Groot a écrit :
> On 30-4-2017 18:30, Alain wrote:
>> Le 17-04-30 à 07:05, Thomas de Groot a écrit :
>>> On 30-4-2017 9:48, Thomas de Groot wrote:
>>>> In fact, the differences are more subtle. For the cube, compare the
>>>> shadows of dragon and egg: their edges show the stone's 
>>>> translucency. In
>>>> my next render I hope to show this better.
>>>>
>>>
>>> In this render:
>>>
>>> - Dragon: no SSLT
>>> - Floor: no SSLT
>>> - Cube: SSLT with 5*translucency vector (was 2* in earlier example)
>>> - Egg: SSLT with 3*translucency vector (was 2* in earlier example)
>>>
>>> The cube is showing markedly more translucency in the shadows cast on
>>> it. I see not much difference in the egg, although if I increase the
>>> translucency exaggeratedly (*100 for instance) the effect becomes
>>> distorted.
>>>
>>> Question: In the wiki about SSLT it is said: "The effect doesn't scale
>>> with the object". Does this mean that SSLT works in the same way as a
>>> scattering media where the amount of scattering has to be compensated
>>> for the amount of media object's scale? It appears so to me at least
>>> although this is not mentioned in the wiki.
>>>
>>
>> It does work similarly to medias, both emissive, absorbing and 
>> scattering.
>>
>> So, if you scale your scene by 10 and want SSLT to look the same, then
>> you need to multiply your SSLT vector by 10. Alternately, you can
>> increase mm_per_unit by the same amount in the global_settings block.
>>
> 
> OK. Only difference would be that with scattering media (for instance) 
> you have to /divide/ the scattering vector by the scale of the container 
> to get the same result, but I get the point indeed.
> 
> I am a bit wary about the mm_per_unit and prefer not to touch it too 
> much, especially if different objects have different scales.
> 

You should set it according to the overall scale of your scene.
The default of 10 mean 1 POV unit = 1 cm. Set it to 1000 if your scale 
is 1 POV unit = 1 m, and 25.4 for 1 inch = 1 POV unit.

In my suggestion, it would make a scene scalled in cm work in mm. So, 
you can change mm_per_unit from it's default of 10 to 1 to reflect the 
change in overall scale.

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On 1-5-2017 14:06, Stephen wrote:
> On 5/1/2017 12:11 PM, Thomas de Groot wrote:
>> On 1-5-2017 12:08, Stephen wrote:
>>> On 5/1/2017 7:50 AM, Thomas de Groot wrote:
>>>>
>>>> I am a bit wary about the mm_per_unit and prefer not to touch it too
>>>> much, especially if different objects have different scales.
>>>
>>> Yes Clipka has put the fear of god into us. :-)
>>> I suppose it depends what you intend by scaling the models.
>>>
>>
>> Indeed, yes. Take my image as example, the dragon is scaled 0.01, the
>> egg 0.25, the cube is not scaled, and the floor 0.50. It seems best to
>> use a standard mm_per_unit and change translucency as needed.
>>
>
> My understanding is that the mm_per_unit is the world/scene scale
>
> And to add to the confusion (on my part at least) meshes can have an
> internal scale and an external one. By internal scale I mean the scaling
> you can change in PoseRay before exporting and external is how you
> change it in PovRay.
> In Blender when using the physics engine the scale should be 1.0. So to
> scale a mesh. You need to edit it and scale it there. Otherwise you get
> unexpected results.
> So if the dragon is an ornament. I would scale it down in PoseRay. If it
> is a statue scale it up in PoseRay. Keep the mm_per_unit as the default.
> Having said that. I have not used SSLT since its RC3. :-(
> So what do I know?
>
>

This all makes a lot of sense indeed. Generally, I do not build a scene 
with a particular scale in mind so I just assemble the elements and let 
the observer do the rest. Thus, a landscape can very well be built by 
either relatively small elements or by big ones, I do not care as I am 
only interested in the final effect.

With SSLT it seems I have to be much more careful.... ;-)

-- 
Thomas

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On 2-5-2017 5:57, Alain wrote:
[snip]
>
> You should set it according to the overall scale of your scene.
> The default of 10 mean 1 POV unit = 1 cm. Set it to 1000 if your scale
> is 1 POV unit = 1 m, and 25.4 for 1 inch = 1 POV unit.
>
> In my suggestion, it would make a scene scalled in cm work in mm. So,
> you can change mm_per_unit from it's default of 10 to 1 to reflect the
> change in overall scale.
>
>

As I wrote in my answer to Stephen, I am shamefully negligent about 
overall scales and just throw together elements to be brewed in the same 
pot. I need to be a bit more careful if I want to include SSLT. :-)

-- 
Thomas

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On 5/2/2017 7:48 AM, Thomas de Groot wrote:

>>
>>
>
> This all makes a lot of sense indeed.

Gosh! a first. :-)

> Generally, I do not build a scene
> with a particular scale in mind so I just assemble the elements and let
> the observer do the rest.

I'm the same. I tend to build my scenes small. For some reason I don't 
like wasting Pov space. Which means I use a lot of decimals but decimals 
are cheap.


> Thus, a landscape can very well be built by
> either relatively small elements or by big ones, I do not care as I am
> only interested in the final effect.

I tend to use Poser figures as a reference. Michael is about six feet, 
in my mind.

>
> With SSLT it seems I have to be much more careful.... ;-)
>

I am sure if Clikpa were about. He would agree. ;-)


-- 

Regards
     Stephen

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On 2-5-2017 9:25, Stephen wrote:
> On 5/2/2017 7:48 AM, Thomas de Groot wrote:
>
>>>
>>>
>>
>> This all makes a lot of sense indeed.
>
> Gosh! a first. :-)

Really?

>
>> Generally, I do not build a scene
>> with a particular scale in mind so I just assemble the elements and let
>> the observer do the rest.
>
> I'm the same. I tend to build my scenes small. For some reason I don't
> like wasting Pov space. Which means I use a lot of decimals but decimals
> are cheap.

They are indeed. However, I try to avoid too small ones. They are more 
difficult to find when they drop to the floor. :-)

>
>
>> Thus, a landscape can very well be built by
>> either relatively small elements or by big ones, I do not care as I am
>> only interested in the final effect.
>
> I tend to use Poser figures as a reference. Michael is about six feet,
> in my mind.

Typically, I scale the figures to the environment they are to live in. :-)

>
>>
>> With SSLT it seems I have to be much more careful.... ;-)
>>
>
> I am sure if Clikpa were about. He would agree. ;-)
>
>

Ah! The Clipka! He seems to have gone on holiday? Shame. He /knows/ he 
cannot go without our permission. ;-)

-- 
Thomas

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On 5/2/2017 8:48 AM, Thomas de Groot wrote:
> On 2-5-2017 9:25, Stephen wrote:
>> On 5/2/2017 7:48 AM, Thomas de Groot wrote:
>>>
>>> This all makes a lot of sense indeed.
>>
>> Gosh! a first. :-)
>
> Really?
>

I meant a first for today.

>>
>>> Generally, I do not build a scene
>>> with a particular scale in mind so I just assemble the elements and let
>>> the observer do the rest.
>>
>> I'm the same. I tend to build my scenes small. For some reason I don't
>> like wasting Pov space. Which means I use a lot of decimals but decimals
>> are cheap.
>
> They are indeed. However, I try to avoid too small ones. They are more
> difficult to find when they drop to the floor. :-)
>

Alt+ LMB + drag scoops them up. :-)
(Bishop3D setting)

>>
>>
>>> Thus, a landscape can very well be built by
>>> either relatively small elements or by big ones, I do not care as I am
>>> only interested in the final effect.
>>
>> I tend to use Poser figures as a reference. Michael is about six feet,
>> in my mind.
>
> Typically, I scale the figures to the environment they are to live in. :-)
>

I was talking my dreams. In truth I scale my scenes by the first object 
I create.

>>
>>>
>>> With SSLT it seems I have to be much more careful.... ;-)
>>>
>>
>> I am sure if Clikpa were about. He would agree. ;-)
>>
>>
>
> Ah! The Clipka! He seems to have gone on holiday? Shame. He /knows/ he
> cannot go without our permission. ;-)
>

As long as he hasn't taken a marching band with him. It is okay. ;-)

-- 

Regards
     Stephen

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On 1-5-2017 14:06, Stephen wrote:
> On 5/1/2017 12:11 PM, Thomas de Groot wrote:
>> On 1-5-2017 12:08, Stephen wrote:
>>> On 5/1/2017 7:50 AM, Thomas de Groot wrote:
>>>>
>>>> I am a bit wary about the mm_per_unit and prefer not to touch it too
>>>> much, especially if different objects have different scales.
>>>
>>> Yes Clipka has put the fear of god into us. :-)
>>> I suppose it depends what you intend by scaling the models.
>>>
>>
>> Indeed, yes. Take my image as example, the dragon is scaled 0.01, the
>> egg 0.25, the cube is not scaled, and the floor 0.50. It seems best to
>> use a standard mm_per_unit and change translucency as needed.
>>
>
> My understanding is that the mm_per_unit is the world/scene scale
>
> And to add to the confusion (on my part at least) meshes can have an
> internal scale and an external one. By internal scale I mean the scaling
> you can change in PoseRay before exporting and external is how you
> change it in PovRay.
> In Blender when using the physics engine the scale should be 1.0. So to
> scale a mesh. You need to edit it and scale it there. Otherwise you get
> unexpected results.
> So if the dragon is an ornament. I would scale it down in PoseRay. If it
> is a statue scale it up in PoseRay. Keep the mm_per_unit as the default.
> Having said that. I have not used SSLT since its RC3. :-(
> So what do I know?
>
>
I have been pondering this a bit. I think that you do achieve the same 
(using meshes of course) if you first do basic transforms (in POV-Ray) 
and /then/ use that copy of the original object with SSLT. In fact, I do 
that exercise quite often:

#declare MyObject =
object {MyMesh_POV_
   transform {MyTransforms}
}

object {MyObject
   material {MyMaterial}
   rotate {MyRotate}
   translate {MyTranslate}
}


-- 
Thomas

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Am 30.04.2017 um 13:05 schrieb Thomas de Groot:

> Question: In the wiki about SSLT it is said: "The effect doesn't scale
> with the object". Does this mean that SSLT works in the same way as a
> scattering media where the amount of scattering has to be compensated
> for the amount of media object's scale? It appears so to me at least
> although this is not mentioned in the wiki.

That depends on what you want to achieve.

If you want the object to look like a larger item made of the same
material, scale the object and use the same SSLT parameters.

If you want the object to look exactly the same, but take up a larger
portion on the screen, scale the object and adjust the SSLT parameters.
(Or zoom in on the object ;))

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Am 01.05.2017 um 14:06 schrieb Stephen:
> On 5/1/2017 12:11 PM, Thomas de Groot wrote:
>> On 1-5-2017 12:08, Stephen wrote:
>>> On 5/1/2017 7:50 AM, Thomas de Groot wrote:
>>>>
>>>> I am a bit wary about the mm_per_unit and prefer not to touch it too
>>>> much, especially if different objects have different scales.
>>>
>>> Yes Clipka has put the fear of god into us. :-)
>>> I suppose it depends what you intend by scaling the models.
>>>
>>
>> Indeed, yes. Take my image as example, the dragon is scaled 0.01, the
>> egg 0.25, the cube is not scaled, and the floor 0.50. It seems best to
>> use a standard mm_per_unit and change translucency as needed.
>>
> 
> My understanding is that the mm_per_unit is the world/scene scale

Indeed.

Also, I might take the opportunity to re-iterate that it is not an SSLT
setting /per se/. It only just so happens that SSLT is currently the
only feature that makes use of it.

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