I'm working on exactly the same.
And had the same problem.
The problem is the z-buffer, it uses a floating-point format.
The physical distance between succeeding z-buffer indices increases greatly
as you go further from the origin. So triangles that are quite close to
eachother, but far from the origin, can get the same z-buffer-value. And
then the rendering might draw a triangle behind a second triangle, when it
should really be before it.
I think that's the main reason for the artifacts.
I "solved" the problem by setting the back clipping plane just "behind" the
earth, and the front clipping plane at about 1km.
Pieter.
----- Original Message -----
From: Kraemer, Max, CTR <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Thursday, March 30, 2000 1:53 AM
Subject: [JAVA3D] Clipping Plane problem?
> I'm working on a 3D display of the Earth. I'm trying to draw everything
to
> scale, so the Earth should have a diameter of about 12 million meters. I
> set my clipping planes in my view object. My front clipping plane is set
> to 0.1 meters, my back clipping plane is set to 100 times the diameter of
> the Earth, and both my front and back clipping policies are set to
> View.PHYSICAL_SCREEN. I initially move my view about five times the
> diameter of the Earth.
>
> When I try to rotate my view about the Earth, however, the 3D display
> flickers and cuts off parts of the Earth in wierd places. I don't have
this
> problem when I cut my scale down so the Earth is 1 meter in diameter.
Does
> anyone have any idea what's going on? Is there anything else I need to
set?
> Is there anything I'm doing wrong?
>
> I'm pretty new to 3D graphics, so any help would be greatly appreciated.
>
>
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