How to place a sketch on a circular edge ?

[Anonymous]

I want to use the circular edge of an elbow fitting to sketch the profile for a sweep to make a tube. How can I convince Fusion 360 to create a sketch on that edge without many support constructions ? None of the construction planes seem to accept being placed on a juicy, flat circle.

There is a workaround in this case : First create the tube's path and place the construction plane somewhere along the straight section inside the elbow fitting. That is what I have done.

[g-andresen]

Hi,

1. try the "Plane Tangent to Face at Point"

2. show a screenshot with the marked area and axis

günther

[Anonymous]

'Plane Tangent to Face at Point' seems to only and at most do what it's name suggests.

The black line shows the tube's path. The vertical, purple line shows the axis. The horizontal, purple line is in the plane on which the sketch should be created.

[davebYYPCU]

The horizontal line, = Plane on Angle

Vertical line (Midpoint) and Curved Black Line (End point) = Plane on Path.

Might help....

[g-andresen]

Hi,

show a real existing object and mark relevant parts and positions

günther

[Anonymous]

'Plane at Angle' actually works, because the circle is perfectly horizontal and I have a line in the circle available, but what if one or two of these conditions were not met ?

'Plane along Path' is what I have used, but what if there were no path available ?

@Anonymous_andresen :

What do you mean with a real existing object ?

[g-andresen]

Hi,

what should be placed where?

günther

[Anonymous]

A sketch should be created on a circular edge, for example the one indicated with the red dots.

[davebYYPCU]

But but but, 

your protests have no substance.

Parts inserted to a document come with inbuilt Origin Planes.

Your blue donut face is suitable for an Offset Plane, at zero distance, at any angle!

Might help

[jeff_strater]

@Anonymous - a sketch is not placed on an edge, but is placed on a plane, which, I think, is the source of the confusion here.  If this face is a plane, you can create a sketch on that planar face, and the circular edge will be a part of that sketch.

If that is not what you are trying to do, then more clarity is needed on your requirements.

[Anonymous]

@davebYYPCU :

The origin planes are invisible for these elbow fittings and the links to the imported files are unbreakable.

There is indeed two flat planes available that are parallel to the circle. There is the one on the reverse side of the blue donut and the grey one (a little visible on the pictures). However, both hare hard to use as bases for offset construction planes. the distance to the circle is hard to measure.
Actually, that is not true. One can create a construction plane on a parallel face, measure the offset distance, delete the construction plane and then create the construction plane on the circle by using the measured offset.

If I understand correctly, there is no way to directly place a sketch or construction plane on a flat, curved edge. One must rely on supporting features or constructions.

@jeff_strater :

I don't care what the sketch is on, but I care what its locatotion is.

So the question is, how can one simply convince Fusion 360 to create a sketch on a plane defined by a planar curved edge ?

[davebYYPCU]

It’s more difficult than Rocket Science!

Construction > Offset Plane

click on the face of the blue cylinder with your curved edge.(red dots)

set distance from that cylinder face to your requirements, (zero)

Click Ok.

OR

Sketch > Create Sketch

select the face of the blue cylinder with the red dots. 

To avoid step one.above.

[jeff_strater]

no, you cannot "simply convince Fusion 360 to create a sketch on a plane defined by a planar curved edge".  What would be needed is a "workplane though edge" where it only works if the edge selected is planar.  Could be done, certainly, and is not unreasonable.  To my knowledge, though, no one has ever asked for this before.

[Anonymous]

@davebYYPCU:

Thanks for the suggestions, but your procedures don't work, as the blue face adjecent to the circle is not flat.

@jeff_strater:

One could add to the 'Create Sketch' the functionality of creation on such curve. I drawback I see is that it would increase the likelyhood of creating a sketch where one doesn't want to (i.e. on such curve), in other words, it would become harder to highlight the place where one really wants the sketch to be created (e.g. a face hiding behind such curve).

An alternative I see is to expand the functionality of the 'Plane Through Two Edges' tool to accept a single curved edge for plane creation. I don't see significant drawbacks.