Thread Subject: 3d graphics large structures

Hello everyone!


I am modeling structures as large 3d-arrays (size about
800*800*800). And I have as many others, memory problems. I
am trying to reduce the amount of needed memory by using
sparsed matrices instead (they only contains ones and
zeros), as slices, with an indexing method, but here is my
problem. I want to visualize my structure, with for example
isosurface. Is there a way to do this? Does anyone know of
any other program to do that?


 Matias

"matias nordin" <matias.nordin@gmail.com> wrote in message news:foha73$cfd$1@fred.mathworks.com...
> Hello everyone!
>
>
> I am modeling structures as large 3d-arrays (size about
> 800*800*800). And I have as many others, memory problems. I
> am trying to reduce the amount of needed memory by using
> sparsed matrices instead (they only contains ones and
> zeros), as slices, with an indexing method, but here is my
> problem. I want to visualize my structure, with for example
> isosurface. Is there a way to do this? Does anyone know of
> any other program to do that?
>
>
> Matias

Your best bet is to create a smaller array to use
as input to something like isosurface. You'll want
to apply a lowpass filter as you decimate to
prevent aliasing. You can do this a block at a
time. You just need to overlap your blocks by
half the width of your lowpass filter. You might
then want to add an option to zoom into one
region for a more detailed view at higher res.

    -MPG-

I had a similar problem before. You basically will either
have out-of-memory or have to decimate the data in MATLAB.
The problem lies in that isosurface() and a few Matlab 3D
visualization functions only take "double" as input.
However, in reality, almost all data for 3D rendering in the
real world are either unit8 or uint16.

Another problem is it seems there is no easy way to combine
the patches generated by different isosurface() calls into a
larger merged patch for visualization. Otherwise you can
generate the isosurface block by block and combine them.

That's why many commercial 3D rendering software (such as
Amira) can handle much larger data-arrays. I think it should
be very easy for MW to change their isosurface() code to
take uint8 or uint16.

"matias nordin" <matias.nordin@gmail.com> wrote in message
<foha73$cfd$1@fred.mathworks.com>...
> Hello everyone!
>
>
> I am modeling structures as large 3d-arrays (size about
> 800*800*800). And I have as many others, memory problems. I
> am trying to reduce the amount of needed memory by using
> sparsed matrices instead (they only contains ones and
> zeros), as slices, with an indexing method, but here is my
> problem. I want to visualize my structure, with for example
> isosurface. Is there a way to do this? Does anyone know of
> any other program to do that?
>
>
> Matias

very common problem with Matlab and isosurface and isonormal
and .... etc

I suggest you move to a 64 bit machine with large RAM (or
-as suggested by another reader- migrate to a 3d
visualization environment more advanced than matlab)

regards
g


"matias nordin" <matias.nordin@gmail.com> wrote in message
<foha73$cfd$1@fred.mathworks.com>...
> Hello everyone!
>
>
> I am modeling structures as large 3d-arrays (size about
> 800*800*800). And I have as many others, memory problems. I
> am trying to reduce the amount of needed memory by using
> sparsed matrices instead (they only contains ones and
> zeros), as slices, with an indexing method, but here is my
> problem. I want to visualize my structure, with for example
> isosurface. Is there a way to do this? Does anyone know of
> any other program to do that?
>
>
> Matias