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25 Dec 2024 11:19:35 EST (-0500)
  CSG cutting slices (Message 1 to 4 of 4)  
From: LikeNoOther
Subject: CSG cutting slices
Date: 4 Oct 2007 05:40:00
Message: <web.4704b40aeb8279c96e4edffd0@news.povray.org>
Hi. I have previously asked for help cutting a 3D model into slices.
The solution did unfortunately not always work. Only in simple 3D models.

Here is what I have done:

#declare MinZ = min_extent(_151stan_toon_).y;
#declare MaxZ = max_extent(_151stan_toon_).y;
#declare Height = MaxZ - MinZ;
//==================================================

intersection {
      object{
              _151stan_toon_
              double_illuminate
      }

      plane{
       y,MinZ+(frame_number/final_frame)*Height

          pigment{
            color rgbf <1,1,1,1>
          }

       }
   }

The rest of the pov file was generated using poseray.
The object name is _151stan_toon.
I want to cut the model into slices similar to ct scans.
(Vertical slices.)
As far as I know all I want to do is get the intersection of the model and
the plane. I made the plane transparent so that I can see the original
colour of the
model.

What happens is that it does cut it into slices but for some reason it
keeps on creating the same slice after a while instead of going further up
the model.

Any help will be appreciated greatly.


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From: Christian Froeschlin
Subject: Re: CSG cutting slices
Date: 4 Oct 2007 06:56:24
Message: <4704c6d8$1@news.povray.org>
LikeNoOther wrote:

> What happens is that it does cut it into slices but for some reason it
> keeps on creating the same slice after a while instead of going further up
> the model.

Hmm, the code looks reasonable to me. If you just
render the plane, does it move as expected?


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From: Chris B
Subject: Re: CSG cutting slices
Date: 4 Oct 2007 07:28:04
Message: <4704ce44$1@news.povray.org>
"LikeNoOther" <eug### [at] gmailcom> wrote in message 
news:web.4704b40aeb8279c96e4edffd0@news.povray.org...
> Hi. I have previously asked for help cutting a 3D model into slices.
> The solution did unfortunately not always work. Only in simple 3D models.
>
> Here is what I have done:
>
> #declare MinZ = min_extent(_151stan_toon_).y;
> #declare MaxZ = max_extent(_151stan_toon_).y;
> #declare Height = MaxZ - MinZ;
> //==================================================
>
> intersection {
>      object{
>              _151stan_toon_
>              double_illuminate
>      }
>
>      plane{
>       y,MinZ+(frame_number/final_frame)*Height
>
>          pigment{
>            color rgbf <1,1,1,1>
>          }
>
>       }
>   }
>
> The rest of the pov file was generated using poseray.
> The object name is _151stan_toon.
> I want to cut the model into slices similar to ct scans.
> (Vertical slices.)
> As far as I know all I want to do is get the intersection of the model and
> the plane. I made the plane transparent so that I can see the original
> colour of the
> model.
>
> What happens is that it does cut it into slices but for some reason it
> keeps on creating the same slice after a while instead of going further up
> the model.
>
> Any help will be appreciated greatly.
>

Hi Eugene,
You could use the #debug directive to write the values out into the message 
stream so that you can trace the problem.
For example, you could add the following lines to your code to look at the 
result of the height calculation, then home in on parts of the calculation 
to see which bits are causing you trouble.

#debug concat("Frame Number: ",str(frame_number,3,3),"\n")
#debug concat("Final Frame: ",str(final_frame,3,3),"\n")
#debug concat("Height Calculation: 
",str(MinZ+(frame_number/final_frame)*Height,3,3),"\n")

Also, while you want to focus on the message stream you can cut the render 
size right down so that each frame renders quicker.

Regards,
Chris B.


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From: Alain
Subject: Re: CSG cutting slices
Date: 4 Oct 2007 09:59:09
Message: <4704f1ad@news.povray.org>
LikeNoOther nous apporta ses lumieres en ce 2007/10/04 05:36:
> Hi. I have previously asked for help cutting a 3D model into slices.
> The solution did unfortunately not always work. Only in simple 3D models.
> 
> Here is what I have done:
> 
> #declare MinZ = min_extent(_151stan_toon_).y;
> #declare MaxZ = max_extent(_151stan_toon_).y;
> #declare Height = MaxZ - MinZ;
> //==================================================
> 
> intersection {
>       object{
>               _151stan_toon_
>               double_illuminate
>       }
> 
>       plane{
>        y,MinZ+(frame_number/final_frame)*Height
> 
>           pigment{
>             color rgbf <1,1,1,1>
>           }
> 
>        }
>    }
> 
> The rest of the pov file was generated using poseray.
> The object name is _151stan_toon.
> I want to cut the model into slices similar to ct scans.
> (Vertical slices.)
> As far as I know all I want to do is get the intersection of the model and
> the plane. I made the plane transparent so that I can see the original
> colour of the
> model.
> 
> What happens is that it does cut it into slices but for some reason it
> keeps on creating the same slice after a while instead of going further up
> the model.
> 
> Any help will be appreciated greatly.
> 
> 
> 
I don't see anything wrong with your code, only some naming inconsistencies, 
like MinZ and MaxZ for a vertival movement where MinY and MaxY would have been 
more straightforward.

-- 
Alain
-------------------------------------------------
Stay out of my head, its a bad neighborhood.


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