Available in DSM 4.0 and up: Use the show 'body interference' option in the Display tab to highlight areas where objects in your design intersect. They will be shown in red, like below:
The quality of the Interference graphic for very small interferences and separations, is dependent upon the graphical rendering quality ( Tessellation 1 > 10 and custom) of displayed parts and the amount of interference or closeness of Bodies / Faces.
Planar faces are very accurately displayed even for very small interferences.
Bodies with faces of curvature are less accurately displayed with low to medium face ( body) tessellation rendering quality.
In the below graphic, it is shown that only HIGH ( level 7 and above) rendering setting shows accurate Interference results and LOW (level 3 and below) shows Interference despite clearances - refer to Hole 6 with pin 5.990 , top left graphic.
It should be noted that even at Normal rendering level 5, very little differences in the Interference graphics are shown between pins of size 5.998 , 6.000 and 6.001 fitting in holes of size 6.
For very close fitting parts where 'Fit's are important for function, a measurement must be made.
Working / setting rendering level ( 7 and above) will result in low FPS, slow to very slow program responses in certain situations and large to very large file sizes!