🚀 go-pugleaf

Thanks to  all for the fast answers .....

Now, i understand why it's called "floating point" ....the precision changes
...

I need float and not double ...Why ?
I am building a 3d word , a big 3d world ..1000 km x 1000 km with 1 cm
precision (= 100 000 000 units).
In this 3d world all the objects have a Point/Vector position (float x,y,z)
...this is what the 3d engine needs (with relatively good precision)..and
what i would like , is to keep in the abstract world representation. I want
to avoid the conversion between world/3d engine co-ordinates ..

I seen now , that this is not a good idea and not really possible ...hmm...

Please ..if you have any suggestion ..ideas ...reply ...

Thank you.

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Karl Heinz Buchegger wrote:

> dataman@cyberdude.com wrote:
> >
> > I am really confused about float precision ..officially it's 3.4 *
> > (10**-38) to 3.4 * (10**+38)
> > But, that does not help me much even it confuse me more ....
> >
> > Here is my problem:
> >
> > I need to define a world of 10 000 000 units .  I need to use float for
> > that . I think to use only the positive part (but will depend from the
> > answer of my question).
> > What precision (after the dot ) can i expect  ?
> >
>
> Not much. If you need to do some arithmetic on the
> coordinates, and you will need to do this, you run
> into big problems. floats usually have a precision
> of 6 or 7 digits. If you do some arithmetics on
> them, the error grows very rapidly, so better count
> with 5 or 6 significant digits. Since you used all
> of them for the integer part, .....
>
> -----------------------------------------------------------
> Karl Heinz Buchegger
> kbuchegg@gascad.at