Most likely drawing errors in your graphics card. I haven't seen this for quite some time.
Some cards/drivers just don't like it when two points are too close to each other.
Try -downloading the latest driver for your card -search this forum for graphics card/driver related issues and compare to your own. -increasing the near clipping plane and decreasing the far clipping plane to increase the precision in the display.
I have installed latest driver (84.21) for my nVidia 6800 LE card but it solved nothing.
As for the camera clipping planes how do I change them, please? I am new to HDN and know only few basic things so only thing I came up with was that I created new camera and looked through it and changed far/near clipping planes in the parameters window but that didn´t solve the problem either.
I am still looking for the same issue in the forums, but it seems noone had the same problem.
Use the Display Options dialog to change the current viewport's near and far clipping plane or the actual camera's near and far clipping planes. Probably both.
To open the Display Options dialog, just hit the “d” key in the viewport and go to the Optimization folder.
To adjust the camera's near and far planes, go to the View folder for the Camera.
I also wonder if using flat shaded or flat shaded with wire also gets rid of the problems.
The Quadro is not necessary if you don't need it's extra capabilities. Just do a search on this forum for graphics cards and see which ones users have found successful. The question which graphics card to use with Houdini comes up and it is always changing as new cards are introduced.
I also wonder if using flat shaded or flat shaded with wire also gets rid of the problems.
Wireframe Bounding Box OK Shaded Bounding Box OK Wireframe OK Hidden Line Invisible BAD Hidden Line Ghost BAD Flat Shaded BAD Flat Wire Shaded BAD Smooth Shaded BAD Smooth Wire Shaded BAD VEX Shaded OK VEX wire shaded OK