Re[2]: Linear3DSet

Hi Bill,

billh@xxxxxxxxxxxxx schrieb am 30.03.2003 um 23:17 Uhr:

>> >

> First, you are using an old version of Ugo's tutorial. Please
> use the version at:


Ok, thank you. Unfortunately google still lists the old

> The slow performance you are seeing for in the
> tutorial is inherent in volume rendering. The 100 x 100 x 100
> volume you want apply it to has 1,000,000 volume points. For
> this will need the fastest 3-D graphics card, which is probably
> nVidea's fastest (whatever that currently is).

Mmh...yes that's right. But how do f.e. computer games
manage this problem? There are lots of games in which
the player can move in a 3d environment with a really
good resolution. And this is even possible with not so
fast graphics cards.

>> By adding the line
>> dispGMC.setTextureEnable(false);
>> the program is extremely more performant than without this line.
>> Unfortunately now the smoother doesn't work any more and many small cubes
>> appear which make the whole plot not very nice. Can I remove these small
>> cubes and tell the smoother to work, without making the program
>> unperformant again ?

> The setTextureEnable(false) causes the volume to be rendered as
> individual points, which is faster than volume rendering.

That's ok. One has to pay some time for the nicer

> The only good alternative is to use a technique that doesn't show
> the whole volume at once, such as an interactive iso-surface (let
> the user interactively select the iso-level using a ContourWidget),
> or an interactive plane slice. That would be the 3-D analog of the
> Python example at:


> You could plot a Real along a vertical axis using
> DirectManipulationRendererJ3D, triggering a CellImpl that
> constructs a Gridded3DSet with manifold dimension = 2 at the
> height of the Real and resamples your 3-D volume Field to
> that Set, then passes the result to the setData() method of
> a DataReference linked to the display.

Ugh, seems to be quite complicated :-) At the weekend
I'd like to present the program and I'd be very happy
about an easier temporary solution. Maybe I could hide
the data points whenever dragging the mouse, i.e. the
user can only move/zoom/... the white coordinate cube
what should be quite fast (at least faster than moving
the whole plot with all its data points). I've already
seen this in other programs and found it quite
comfortable. Do you know how I can do this with VisAD ?
In some days/weeks I'll probably also try your solution
from above.