Moving a sketch profile generates red error projections in a sketch downstream

[threeleggedcat.shop]

Hi,

Moving a profile generates red error projections in a sketch downstream. There are two projects posted: "...before" has the User Parameter mainBallPathRadius set to 140 mm; in "...after" this is set to 135 mm. The drawing depicts sketch "Track support profile" with the red error projections. There does not seem to be a way to fix them as in "Manage Lost Projections".

I've tried creating two small extrusions of track to use as a projection template (verses the sketch). The bodies move if their underlying sketch shifts, but not the projected profiles.

I originally had everything crammed into one sketch, but that just created sketches with way too many constraints to be stable and lockable. This attempt to "do the right thing" by making simpler sketches and linking them via projections created another set of problems.

Any suggestions on how to improve my workflow would be appreciated. More info below.

The first (originating) sketch ("Track path centered") contains two rolling ball track profiles. The second sketch ("Track support profile") projects the track outlines and builds a supporting body into which the track is inserted. The channel needs an offset from the original track profile for ease of insertion. The Offset Face tool could be used, but these shapes may get complicated and selecting all the faces to offset is tedious and problematic... if it doesn't meet failure at the hands of the geometry engine demon.

thanks,

mark

[g-andresen]

Hi,

You must specify in the "Master Outlines" sketch whether the lower circle set should be tangent to the outer circle or the distance of the centers to the center of the main circle should be determinative.

Screencast

günther

[threeleggedcat.shop]

Hi,  Not sure I understand.  The Master outlines sketch is fully constrained.  The center of the group of smaller circles are centered about the Origin.  There is another project level sketch importing geometry from a base that is not going to change.  I fixed that whole thing but still could not get the two sketches to move properly ("Track path centered" does move.  mark

[g-andresen]

Hi,

Please check the relation of mainBallPathRadius and supportPostDiameter_2 if the outer of the 4 circles should be tangential to circle at the same time.

günther

[threeleggedcat.shop · Accepted solution]

Hi ... and thanks for the replies!

They should not.  The mainBallPath may change in relation to it's surrounding support posts.

I did manage to get three sketches to cooperate in a very simple design.  So I suspect I need to go back and make sure I'm projecting what I think I'm projecting.  One of my Fusion experiences is that starting a new design with judicious copy and pasting is better than changing an existing design.  That may be the case here.

mark

[threeleggedcat.shop]

Oh oh, I did find a fixed point in one of the sketches but it didn't seem to fix it.

In the same design, I created a new sketch on the tracks (YZ) plane.  Projected the track profiles and made a 1 mm outline for each track.  Changing mainBallPath does move the 1 mm outlines.  Adding a line from the base of one to the other results in the sketch NOT moving to follow mainBallPath.  What does work is to alter the Track path centered sketch to add the fatter 0.10 mm outlines to both track profiles.  Then create a sketch with those fatter outlines as projections and add the track support profile to that.

So I'm happy to have a solution.

mark