# Re: [osg-users] Jittering/Flickering geometry problem

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Am 2/16/2017 um 5:48 AM schrieb umesh ramesh:
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```Hi Sebastian,

Thanks for the prompt reply. As I had written earlier, I do not prefer to generate
my road geometries at origin & translate far off where they are located (maybe
thatâ€™s the last option that I shall use).
I am under the impression that there might be other techniques to tackle this
problem.
```
Most likely not. The other problem usually occurring is z-fighting which also is a precision problem. This can be tackled via logarithmic depth buffers etc. but as you were talking about flickering involving only one geometry, depth-precision is non of the problems (For z-fighting you'd need at least two primitives).
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Think about the problem this way: Your geometry is a _local_ description of road-piece that can be _placed_ where you like it to be on a terrain that is _placed_ where you like it to be. This way relative coordinates will stay in the boundary of your viewing frustum. And having a road-piece of several thousand kilometers is simply not feasible.
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```I think, VirtualPlanetBuilder is generating the Terrain Tiles in the way you
But, FlightGear too has terrain & roads all over & they are rendered properly.
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There are several other techniques including texture splatting and so on, to put decals onto terrain. But the problem arising with multiple geometries on top of each other is usually z-fighting ...
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```Do the similar Projects use the same basic theory that you had written?
It will be helpful if you can give additional insight into this.
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There is no way to have coordinates in the scale described in your example and single precision. Usually one needs to transform the coordinates around the center of the data-set by transforming either the geometry coordinates or by using a transform in the scenegraph. The other, in case relative precision is not-important is to simply scale the coordinates. But basically it all boils down to send reasonably "small" coordinates to the GPU. Believe me, i had to learn this the hard way while implementing shader-based geocentric effects ;-)
```This of course doesn't mean that I know every trick.

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```Cheers
Sebastian

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```Cheers,
umesh

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http://forum.openscenegraph.org/viewtopic.php?p=70205#70205

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