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I found, that some faces are blinking (like Moire effect) while rotating in preview.
Is this normal?
Reboot didn't help. Blender version is 2.76
OS is Windows 10 prof.
Video is GeForce GTX 770.
The following message appears upon start:
(AL lib: (EE) UpdateDeviceParams: Failed to set 44100hz, got 48000hz instead)
I found it is the problem of my model, since it affects only half of it:
I was extruding circle and the split is located exactly where I started. I.e., right half was extruded from the circle to the right, and the left half was extruded from the left vertices to the left.
Also I noticed extruding behavior changed when I was doing this: Unconstrained extrusion?