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Strange thing

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wacko
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Joined: 2006-02-17

Hello folks.
I'm writing a program that canstructs a 3D mesh of a hip bone from a series of 2D CAT-scans.
The raw input data are the traced 'raw' contour points of every piece of bone in every scan.
the resulting 'raw' mesh takes up about 16000 faces. when i do an edge division in the XZ plane to smooth the contours, this number climbes to 32000 for d=2, 64000 for d = 4 etc... (as expected)
Now the problem is that parts of my mesh seem to completely vanish when after applying this smoothing.
Is 32000 really to many triangles? Because when i just render a random subset of the smoothed bone mesh this renders perfectly :-s
I know the smoothing works perfect(feedback in my 2D Swing view) and also a partially smoothed mesh renders okay in the 3D view. It just seems that once a certain face count reached, J3D discards the first inserted data to fit in the new data in a limited memory heap?

Any, ANY suggestions would be tremendously appreciated!
:-) Wacko

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wacko
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Joined: 2006-02-17

I've installed OGL/J3D sdk and this didn't solve my problem.
I've discovered that the problem of vanishing mesh parts only occurs when total face count hits the 22k!

I'm using a list of Shape3D ectended objects, constructed using IndexedTriangleArray's.
Face count per Shame/array never exceeds 2000 :-s and i have around 100 of those Shapes3D in my one and only 'worldObjectsGroup' branchGroup.

I can successfully render any random combination of this Shape3D collection,as long as face count stays under 22000. GFX/Processor Performance and ram useage are not the problem.

Anyone another idea? I'm reaaly stuck with this (literally+ figuratively :-()

aces
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Joined: 2003-07-17

Just curious...
What is your vcard model and drivers version ?

Another tip is using -Dj3d.debug=true option, but I recomend to use the J3D 1.3.2 build8 for detailed output. This build is OGL and D3D switchable using -Dj3d.rend option.

java -Dj3d.debug=true My3DApplication

or below for Direct3D

java -Dj3d.debug=true -Dj3d.rend=d3d My3DApplication

wacko
Offline
Joined: 2006-02-17

Hey Allesandro, thanks alot for the tip!
I'll look into it.

Alessandro Borges

32000 is big number, but not too much polygon count for today vcards.
But if you are using Direct3D there is limit in the vertexBuffers index. Single
meshes with high polycount can reach this limit. In this case just try Java3D
OpenGL version. There is a thread in this list about it.

Alessandro

--- java3d-interest@javadesktop.org escreveu:
> Hello folks.
> I'm writing a program that canstructs a 3D mesh of a hip bone from a series
> of 2D CAT-scans.
> The raw input data are the traced 'raw' contour points of every piece of bone
> in every scan.
> the resulting 'raw' mesh takes up about 16000 faces. when i do an edge
> division in the XZ plane to smooth the contours, this number climbes to 32000
> for d=2, 64000 for d = 4 etc... (as expected)
> Now the problem is that parts of my mesh seem to completely vanish when after
> applying this smoothing.
> Is 32000 really to many triangles? Because when i just render a random
> subset of the smoothed bone mesh this renders perfectly :-s
> I know the smoothing works perfect(feedback in my 2D Swing view) and also a
> partially smoothed mesh renders okay in the 3D view. It just seems that once
> a certain face count reached, J3D discards the first inserted data to fit in
> the new data in a limited memory heap?
>
> Any, ANY suggestions would be tremendously appreciated!
> :-) Wacko
> ---
> [Message sent by forum member 'wacko' (willem_mahy)]
>
> http://www.javadesktop.org/forums/thread.jspa?messageID=33888葠
>
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> To unsubscribe, e-mail: interest-unsubscribe@java3d.dev.java.net
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>

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