Coincident Issue

[contact59W8V]

I'm struggling to do something very simple in Fusion 360. I want to cut out a half circle on an arc, and want said circle to be coincident to the arc. Except its like the arc isnt there. I made a video to show the problem better.

https://www.youtube.com/watch?v=kGrzLtS2XVI

[jhackney1972]

The reason you cannot connect the center of the circle to the edge of the arc section is because the edge has not been projected into your sketch.  Take a look at the screencast.

Next time please attach your model so the forum users and address you specific problem.  Also, please use Autodesk Screencast for two reasons, it is much clearer to see and it shows the commands that you are using at the bottom of the display.  If you do not know how to use Screencast, here is a link to help you out.

[davebYYPCU]

Screencast software integrates with Fusion, and will show us your mouse clicks and other Fusion mechanisms.

After you draw the circle, turn off the body that contains your arc.(Eyeball)  

There now you see why you can’t use it, there is nothing else in your sketch, to snap to.  

So it’s Create Sketch, 

Use create > Project > Project, Select the arc, it will supply a purple arc to use. Hit Ok.

Hide the orange body, with the body eyeball.

Draw circle, the centre point will snap to the purple line, 

Show the orange body.

Extrude > Cut shows a red preview, this expected behaviour, and not an error, now that you have the purple arc, you will also cut the circle profile into two parts.  Again expected behaviour, you will have to select both to cut a circle.

Now - Cutting a Slot for clamping has nothing to do with your side on activity.

Create a sketch on an Offset Plane above or below the clamp, 

draw an appropriate slot, 

Extrude cut the slot through the bracket. Down or up through in the vertical direction.

Might help....

[davebYYPCU]

Like this?

Step up the timeline in my file, 

Add dimensions to suit....

Might help....

[contact59W8V]

I read your response three times and have no idea what you were trying to say.

[davebYYPCU]

I was referring to your video, and the steps you took.

If at the time you drew the circle, you hide the body, what's left?  Just your current sketch articles.

When sketching, Fusion is inconsistent with snapping to objects that are not in the same sketch.  

Do you know about the eyeball and it's advantages on clarity.

The next part was covered in John's video.

Sorry to confuse...

[contact59W8V]

Thanks for the quick reply on projection. What I don't understand is how it worked once when I did it without projection. That's the thing that drives me insane about this program. I'm following a tutorial where it worked fine for that person, but not for me. Do I always have to use projection when doing this type of thing? What if I selected the face of the body that the sketch was on? I tried doing it directly on the sketch itself but it didn't work there either. I feel like Im rolling the dice half the time and hoping Fusion does what I want it to.

[jhackney1972]

There are a lot of setting in Fusion 360 that someone else may have set and you have not.  A guess here is that the person doing the video, you are watching, may have turned on "Auto project geometry on active sketch plane".  I normally use this but in my screencast I went ahead and used the project command to make sure you understood the concept.  Everyone develops their own style and all CAD applications have different settings so it takes time and practice.  Be patient with yourself, you will soon understand the concept and select the setting that help you.

[contact59W8V]

I just checked and I already had that setting on by default. Which begs the question, why didn't it work?!? The reality is I don't have time to sit and learn by trial and error dealing with the random quirks and mysteries of this frustrating program. Ive lost a lot of money screwing around trying to make the program work on various projects instead of running my CNC or working in the shop. Multiple times Ive said screw it and quickly drew what I needed in a plain CAD program and figured the rest out on my own with templates. There has to be a better way to learn this.