Bad rendering on screen


lately, when zooming in the rendering of my screen is very bad. edges and isocurves dissapear, also when selecting ann object, the yellow llines are almost unvisible.

see pictures below. anyone any idea what causes this problem?

Is the model far from the world origin 0,0,0 ? If so, does the display improve if you move it closer? You could also try the command TestZbiasFactor and enter a small number like .001. This can help with the edges being drawn really far from 0.

Post a 3dm that shows the issue if you still need help please.