Why Does Fusion 360 Project So Much Geometry?

[tranq006]

Hello All,

When I first started with Fusion 360, it seemed that when referencing things in sketches, Fusion could reference edges/faces etc. that were parallel or in same plane of current sketch without actually making projection lines (such as Solidworks works). However, these days whenever I reference or dimension almost any edge or face in a sketch, Fusion automatically makes projections of that geometry (see attached image of sketch with simple referenced geometry that Fusion automatically projected tons of lines). 

Of course, projections have a huge tendency to fail downstream or when making edits later on, and is undesirable. Is there something I am doing wrong or a better way to do this?

 

[jhackney1972 · Accepted solution]

I am guessing you need to modify your Fusion Preferences.  Remove the one with the red arrow and consider the one with the comment.

[djlunty]

@tranq006 

In Preferences>Design turn off (uncheck) "Auto project geometry on active sketch plan"

[jeff_strater]

"When I first started with Fusion 360, it seemed that when referencing things in sketches, Fusion could reference edges/faces etc. that were parallel or in same plane of current sketch without actually making projection lines (such as Solidworks works)"

Pretty sure that is not true.  I've been working on Fusion from the very beginning, and even with "Auto project edges on reference", a projection would occur.

"projections have a huge tendency to fail downstream or when making edits later on"

Exactly!  Which is why I turn the auto project setting off, and manually project ONLY what I need.

"such as Solidworks works"

I am 90% sure that even Solidworks actually does the projection, they just don't show it to you.  No real other way to do it, as far as I know.

[tranq006]

Interesting, well when it projects in Solidworks them seem to fail less frequently (as supposed to doing convert identity within Solidworks, which fail often)

[tranq006]

Thanks! These two settings seem quite similar, not totally sure what the difference is

[tranq006]

When I turn the setting off, I cannot snap to geometry, but then when I still reference the geometry manually, projection lines result. Please see attached video

https://app.screencastify.com/v3/watch/rdEdFPIszM7s0XLdn3Ba

[djlunty]

@tranq006 

The idea for turning off the settings is so that you only project what you need as per @jeff_strater comment near the end of his post.

Your example of the colinear constraint was something I have never used with out doing a projection first.  I don't believe you can "connect" objects as you want with out some type of projection.  

[tranq006]

I guess my surprise is because in solidworks, doing the two operations (snapping to geometry within the sketch plane) would never require any sort of projection or convert entities

[jeff_strater]

the projection happens (that is how the sketch knows about it).  My guess is that the projection is just hidden from you.  But, I admit:  I have no inside knowledge of Solidworks internals.