Why some faces in your CAD Model flicker


In the picture below, you can see this annoying bug that you probably may have noticed before.












This is not just an issue in Autodesk Inventor or Fusion 360 but many other 3D modelling packages,

It also affects both solid and mesh modelling.

You may have already surmised the cause of it,

It is caused  when two faces share the same plane,

Simply, this is due to the programs do not know which face should be rendered on screen,

So, it jumps between rendering both faces, and you get that odd flashing that jumps around.

The fix for this in Inventor is to give a very small offset between the faces, leaving a small “Air Gap.”

As the two faces are now no longer sharing the same plane the flickering  should stop.

The main issue with this being is that it may interfere with any manufacturing or detailed drawings,

This is especially evident when tolerances are tight.

I would recommend using the Save As function, then saving the model as separate model, then editing it.

Just remember that these two models will work independently,

This means that if there are any design changes, they will need to be updated on both models or saved out.


If you are using Fusion 360 you can also try using dielectric priority control,

Please see my blog in the link below on it:


what it does in a nutshell, is allow you to set the priority of which face will be given priority when being rendered.