[comp.sys.sgi] polf errors on 4D 70 GT

jsivier@UX1.CSO.UIUC.EDU (Jonathon Sivier) (02/24/90)

    Has anyone else noticed anything like this?  I am displaying a large
number of objects on a Iris 4D 70 GT. There are at least several hundred
polygons on the screen at any given time.  As I move my POV around various of
the polygons will have their centers clipped out.  The left and right ends are
displayed correctly but the center portions are not there.  These polygons
tend to be long and thin, but not extremely so.  They are in objects and
were created using polfi.  I tried making them with floating point coords
using polf but it had no effect.  I have backfacing on.

    If anyone has any suggestions I would like to hear them, could this be a
hardware problem.  I also notice this problem on the flight demo program, but
it isn't as pronounced.

Thanks

Jonathan Sivier
jsivier@ux1.cso.uiuc.edu

sherman@ux1.cso.uiuc.edu (02/25/90)

/* Written 12:10 pm  Feb 23, 1990 by jsivier@UX1.CSO.UIUC.EDU */

>     Has anyone else noticed anything like this?  I am displaying a large
> number of objects on a Iris 4D 70 GT. There are at least several hundred
> polygons on the screen at any given time.  As I move my POV around various of
> the polygons will have their centers clipped out.  The left and right ends are
> displayed correctly but the center portions are not there.  These polygons

Sounds to me like the near clipping plane needs to be nearer.  Did you try
this Jon?

> 
> Thanks
> 
> Jonathan Sivier
> jsivier@ux1.cso.uiuc.edu

/************************************************************************/
/* Bill Sherman								*/
/* National Center for Supercomputing Applications			*/
/* University of Illinois						*/
/* Champaign-Urbana							*/
/*									*/
/* Internet: wsherman@ncsa.uiuc.edu					*/
/*									*/
/*   "You want to do mankind a real service?  Tell funnier jokes."	*/
/* 		Og							*/
/************************************************************************/