Show Part Intersections on Drawing Views

S_Regula

Can anyone shed some light on the thought behind having the "Show Part Intersections" toggled OFF by default when placing views on a drawing? It seems as though I am almost always changing views to "Show Part Intersections" in order to properly show the view. I have yet to see why this is even an option, let alone toggled "OFF" by default. For smaller scales/views, the difference between showing and hiding part intersections is not really noticeable. But for larger views/scales, the difference is obvious. I'm just curious as to why "Hide Part Intersections" would be favorable over "Show Part Intersections"?  

S1mon

I haven't played with this setting, but I'll take a wild guess: performance.

PeteYodis

@S_Regula Imagine the Onshape system is processing lots of drawings of assemblies all the time with lots of interferences that users don't really care about, but have intentionally modeled.  Things like press fits, helical threaded fasteners from McMcaster Carr in holes with interferences (my favorite),  etc...  To constantly process the part intersections on these cases adds to longer view generation times for views as a default experience.  Users may only really care about a subset of these cases.  For now we have defaulted to this being off for performance reasons.  We occasionally help users discover this setting, and when we do they are sometimes unaware of even having interferences in the model -  so perhaps it's a check on the last line of defense.  We could give more control over this area, but have not received a lot of feedback that we need to just yet.  As always, we are listening.  

eric_pesty

I'm wondering if the OP isn't using "show part intersection" to get small lines showing on views of large "things" instead of switching the view to "high quality"...
The setting should only make a difference if you have parts that are interfering with each other, which would typically not be the "norm" (depending on what you are designing obviously...)

raj_Onshape

Show Part Intersections only helps if two parts in an assembly or part studio are physically interfering with each other.  This is not usual in the real world. Turning this option has an adverse affect on performance as one needs to compute intersections between parts before doing rendering of intersecting edges. If you model your parts like the real world you seldom need this option turned on. 

If you have to turn this option quite a lot in drawings you should reconsider how you design your parts/assemblies and actually do a boolean operation in the part studio before you create a drawing. Otherwise things like mass/volume/surface area might be incorrect for downstream operations.

S_Regula

This happens in my models when there is thread engagement between 2 parts. Since threads are not easily modeled, I use the major diameter for the internal or external thread for each. As a result, the 2 parts have "interference" between them which is by design. When the assembly is put onto a drawing and "show part intersections" is turned off, the parts which have the thread engagement look a bit off (see attached screw threading into hole): I now understand the reasoning. I will just have to continue to toggle "show part intersections" when needed.