Greetings.

My suggestion to all POV-Ray developers: the render window should be
featuring a selection lasso rather than the conventional selection
rectangle. That would make it possible to limit a new selection rendering to
only the areas really needed, while the conventional selection rectangle
might very often contain areas not desired to render again (as rendering
unimportant areas slows down unneccessarily).

Sincerely,

Sven

Post a reply to this message

>
>My suggestion to all POV-Ray developers: the render window should be
>featuring a selection lasso rather than the conventional selection
>rectangle. That would make it possible to limit a new selection rendering to
>only the areas really needed, while the conventional selection rectangle
>might very often contain areas not desired to render again (as rendering
>unimportant areas slows down unneccessarily).
>

Hi Sven.

A common practice is to use #declare and #if statements in your scene to control the
rendering of
certain objects or groups of objects.  For example, you may declare something like
this at the top
of your scene:

#declare draw_sphere true;

Then have an #if statement in your scene to control rendering of the object:

#if ( draw_sphere )
  ... code for the sphere goes here ...
#end

I often use this technique to control detailed vs. simple textures also.



Kyle

Post a reply to this message

"Kyle" <hob### [at] gatenet> schreef in bericht
news:ev3d525uhl58kg8ckme3vvns1q4ng0fh8g@4ax.com...
> >
>
> Hi Sven.
>
> A common practice is to use #declare and #if statements in your scene to
control the rendering of
> certain objects or groups of objects.  For example, you may declare
something like this at the top
> of your scene:
>
> #declare draw_sphere true;
>
> Then have an #if statement in your scene to control rendering of the
object:
>
> #if ( draw_sphere )
>   ... code for the sphere goes here ...
> #end
>
> I often use this technique to control detailed vs. simple textures also.
>
>

I was going to suggest the same thing!!! My scenes generally start with a
whole array of such switches, turning objects on or off. Combined with the
selection rectangle, testing is easy. I do not feel the need of a lasso,
frankly.

Thomas

Post a reply to this message

Thomas de Groot nous apporta ses lumieres en ce 02/05/2006 02:41:
> "Kyle" <hob### [at] gatenet> schreef in bericht
> news:ev3d525uhl58kg8ckme3vvns1q4ng0fh8g@4ax.com...
> 
>>Hi Sven.
>>
>>A common practice is to use #declare and #if statements in your scene to
> 
> control the rendering of
> 
>>certain objects or groups of objects.  For example, you may declare
> 
> something like this at the top
> 
>>of your scene:
>>
>>#declare draw_sphere true;
>>
>>Then have an #if statement in your scene to control rendering of the
> 
> object:
> 
>>#if ( draw_sphere )
>>  ... code for the sphere goes here ...
>>#end
>>
>>I often use this technique to control detailed vs. simple textures also.
>>
>>
> 
> 
> I was going to suggest the same thing!!! My scenes generally start with a
> whole array of such switches, turning objects on or off. Combined with the
> selection rectangle, testing is easy. I do not feel the need of a lasso,
> frankly.
> 
> Thomas
> 
> 
Also, rendering an irregular shaped area could ultimately be slower than a slightly to
large area. 
This will be due to a substentialy more complex code. The code for a simple square
section is 
simple: you limit the region to render. That for an arbitrary free-hand capture will
need to test 
every pixel against the desired area. You may also need to render, but not display, in
a, square, 
region larger than the selected area.

-- 
Alain
-------------------------------------------------
File not found. Should I fake it? (Y/N)

Post a reply to this message

Hmm. A pity. Alright, thanks.

Sven



> Also, rendering an irregular shaped area could ultimately be slower than a 
> slightly to large area. This will be due to a substentialy more complex 
> code. The code for a simple square section is simple: you limit the region 
> to render. That for an arbitrary free-hand capture will need to test every 
> pixel against the desired area. You may also need to render, but not 
> display, in a, square, region larger than the selected area.
>
> -- 
> Alain

Post a reply to this message

Alain wrote:
> Also, rendering an irregular shaped area could ultimately be slower than 
> a slightly to large area. This will be due to a substentialy more 
> complex code. The code for a simple square section is simple: you limit 
> the region to render. That for an arbitrary free-hand capture will need 
> to test every pixel against the desired area. You may also need to 
> render, but not display, in a, square, region larger than the selected 
> area.

While I don't necessarily think we need this feature, I don't think it 
would be that bad.  For each line, you could just store the beginning 
and ending points (assuming only convex shapes were allowed) and render 
a straight line across.

...Chambers

Post a reply to this message

Hi Chambers and Alain,

I am also a programmer and when suggesting the new lasso feature, I had 
exactly in mind what Chambers explains.

But on the other side, I am not sure how and how much it affects the speed.

I would like to have here an opinion by someone from the POV-Ray team, as 
they know the source code the best, and can also very fine estimate how the 
new lasso would affect calculation amount and speed.

Greetings,

Sven


"Chambers" <ben### [at] pacificwebguycom> schrieb im Newsbeitrag 
news:445a1426$1@news.povray.org...
> Alain wrote:
>> Also, rendering an irregular shaped area could ultimately be slower than 
>> a slightly to large area. This will be due to a substentialy more complex 
>> code. The code for a simple square section is simple: you limit the 
>> region to render. That for an arbitrary free-hand capture will need to 
>> test every pixel against the desired area. You may also need to render, 
>> but not display, in a, square, region larger than the selected area.
>
> While I don't necessarily think we need this feature, I don't think it 
> would be that bad.  For each line, you could just store the beginning and 
> ending points (assuming only convex shapes were allowed) and render a 
> straight line across.
>
> ...Chambers

Post a reply to this message

Wasn't it Sven Littkowski who wrote:
>Hi Chambers and Alain,
>
>I am also a programmer and when suggesting the new lasso feature, I had 
>exactly in mind what Chambers explains.
>
>But on the other side, I am not sure how and how much it affects the speed.
>
>I would like to have here an opinion by someone from the POV-Ray team, as 
>they know the source code the best, and can also very fine estimate how the 
>new lasso would affect calculation amount and speed.

One awkwardness might be the difficulty of doing a shift-lasso to
remember a permanent region.

With the existing shift-drag rectangle, only four parameters need to be
appended to the command line, but an arbitrary shape might require a
very large number of parameters.

Without the ability to set the lassoed region permanently, you'd have to
re-lasso the area after each test run, even if the last test failed so
badly that nothing was visible in the target region.

-- 
Mike Williams
Gentleman of Leisure

Post a reply to this message

Thanks for your replay, Manuel.

However, I am not sure if I understood your points right, let me repeat the 
way I understood. So you can correct me.

"When selecting with a rectangle, POV-Ray is currently remembering the 
outlines and can therefore repeat a render just like that. However when 
using a lasso shape (irregular shape) with more corners than a rectangle, 
POV-Ray could not automatically re-render that selection.

And it is not possible to select (based on what you see so far after a 
rendering) to select a part of the scene so exactly as you could with a 
rectange."

Is this what you meant?

Sven




"Mike Williams" <nos### [at] econymdemoncouk> schrieb im Newsbeitrag 
news:Qq3### [at] econymdemoncouk...
> Wasn't it Sven Littkowski who wrote:
>>Hi Chambers and Alain,
>>
>>I am also a programmer and when suggesting the new lasso feature, I had
>>exactly in mind what Chambers explains.
>>
>>But on the other side, I am not sure how and how much it affects the 
>>speed.
>>
>>I would like to have here an opinion by someone from the POV-Ray team, as
>>they know the source code the best, and can also very fine estimate how 
>>the
>>new lasso would affect calculation amount and speed.
>
> One awkwardness might be the difficulty of doing a shift-lasso to
> remember a permanent region.
>
> With the existing shift-drag rectangle, only four parameters need to be
> appended to the command line, but an arbitrary shape might require a
> very large number of parameters.
>
> Without the ability to set the lassoed region permanently, you'd have to
> re-lasso the area after each test run, even if the last test failed so
> badly that nothing was visible in the target region.
>
> -- 
> Mike Williams
> Gentleman of Leisure

Post a reply to this message

"Sven Littkowski" <sve### [at] jamaica-focuscom> wrote:
> Thanks for your replay, Manuel.
>
> However, I am not sure if I understood your points right, let me repeat the
> way I understood. So you can correct me.
>
> "When selecting with a rectangle, POV-Ray is currently remembering the
> outlines and can therefore repeat a render just like that. However when
> using a lasso shape (irregular shape) with more corners than a rectangle,
> POV-Ray could not automatically re-render that selection.
>
> And it is not possible to select (based on what you see so far after a
> rendering) to select a part of the scene so exactly as you could with a
> rectange."
>
> Is this what you meant?
>
> Sven
>
>

What he means is that when selecting with a rectangle, only points (4
numbers) are needed to describe the lower left and upper right corners of
the selection.  When you do this, you canoptionally have these written to
your ini file for rerendering the exact selection.  These are written to
the ini as Start_Column, Start_Row, End_Column and End_Row (+SC, +SR, +EC,
+ER).  These can also be appended manually to the commandline to render
onlya region.  However with a lasso selection, many more values need to be
used to describe the region.  It is likely possible to do this, however,
adding it to the ini file or command line would not be convenient.
Not to say that it can't be done, but it would likely have to implemented
differently than the current rectangle selection.

-tgq

Post a reply to this message