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LordWilmore
11-17-2011, 04:58 AM
Hi,

When I render my 3D model, which only comprises individual points rather than polygons, I get a strange effect when rotated/zoomed at certain levels. The effect is hopefully viewable in the attached file showing a sample model of a scanned spray can.

There is actually an even distribution of points across the entire model, but some aliasing effect is causing large "holes" in the view, such as the stripes that are visible as white horizontal-ish stripes above the "400ml" label at the bottom of the can.

I am using third party 3D renderer, which I know utilises OpenGL for its rendering, but I unfortunately do not have the code. I was hoping that somebody would shout "oh yes, that's the ${professorName} effect" and tell me which flag to enable so that I could then pass that information on to the developers of the third party renderer. Any clues?

Thanks
LordWilmore

ZbuffeR
11-17-2011, 05:55 AM
I would say just increase point size until the effect disappear.
Or use MSAA.

You have to know that above solutions will only help in certain cases, in general there is no clean way to solve the sampling problem (short of super brute force like analytic pyramid tracing that you probably don't want).

LordWilmore
11-20-2011, 05:36 AM
Fair enough. That's probably why they haven't implemented anything then!

Thanks for the response.
Lord Wilmore

remdul
11-21-2011, 03:40 AM
Depending on how your 'third party 3D renderer' is implemented in you application, you might have some luck placing a "glPointSize" call in there somewhere, but that's unlikely to give you much control over quality nor completely solve your problem.

As ZbuffeR indicated, rendering point clouds as solids can be complex. Usually it involves converting the data to triangle soup, although there may be some voxel-like solutions (which will also become very involving if you want good performance). However, if you're looking for another shortcut, can probably find some useful open-source libraries out there, google is your comrade.