Re: Geometry expansion statement

Dear Chris,
    I agree manual need to be clarified a bit.

The application of the scaling matrix to the expansion is shown (for
example) in the slides of the JLab course
https://www.fluka.org/free_download/course/jlab2012/Lectures/16_Advanced_Geometry_0412.pdf

8.4.4} Geometry directives: usage notes
[...]
   Directives $Start_expansion and $Start_translat are applied when reading
   the geometry: therefore they imply no CPU penalty. Directive
   $Start_transform, instead, is applied at run-time and requires some
   additional CPU time.
[...]

-> Run time matrix transformation is used only for $Start_transform.
cheers

Vittorio

On 17/06/2012 15:31, Chris Theis wrote:
> Dear colleagues,
>
> I was recently looking into some geometry statements of FLUKA and there is some contradiction in the manual regarding the
> $start_expansion statement for which I would appreciate some clarification.
>
> The manual states that the statement provides the expansion/reduction of body dimensions, whereas the example given suggests that
> actually a scaling matrix is applied to the object instead of a true expansion, which is applicable to the object's dimensions only
> and not to the object's position.
>
> I would appreciate if somebody could comment what the code is actually doing in this case.
>
> Thanks a lot
>
> Chris
>
>

-- 
Dr. Vittorio Boccone - University of Geneva
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